Utils (Spark 2.1.1 JavaDoc)

Object
- org.apache.spark.util.Utils

```
public class Utils
extends Object
```
Various utility methods used by Spark.

Constructor Summary

Constructors
Constructor and Description

Utils()

Constructors
Constructor and Description
`Utils()`

Method Summary

Methods
Modifier and Type	Method and Description
`static String`	`BACKUP_STANDALONE_MASTER_PREFIX()` An identifier that backup masters use in their responses.
`static String`	`bytesToString(long size)` Convert a quantity in bytes to a human-readable string such as "4.0 MB".
`static long`	`byteStringAsBytes(String str)` Convert a passed byte string (e.g.
`static long`	`byteStringAsGb(String str)` Convert a passed byte string (e.g.
`static long`	`byteStringAsKb(String str)` Convert a passed byte string (e.g.
`static long`	`byteStringAsMb(String str)` Convert a passed byte string (e.g.
`static void`	`checkHost(String host, String message)`
`static void`	`checkHostPort(String hostPort, String message)`
`static boolean`	`chmod700(java.io.File file)` JDK equivalent of `chmod 700 file`.
`static Class<?>`	`classForName(String className)` Preferred alternative to Class.forName(className)
`static boolean`	`classIsLoadable(String clazz)` Determines whether the provided class is loadable in the current thread.
`static <T> T`	`clone(T value, SerializerInstance serializer, scala.reflect.ClassTag<T> evidence$2)` Clone an object using a Spark serializer.
`static void`	`configTestLog4j(String level)` config a log4j properties used for testsuite
`static java.net.URI`	`constructURIForAuthentication(java.net.URI uri, org.apache.spark.SecurityManager securityMgr)` Construct a URI container information used for authentication.
`static long`	`copyStream(java.io.InputStream in, java.io.OutputStream out, boolean closeStreams, boolean transferToEnabled)` Copy all data from an InputStream to an OutputStream.
`static java.io.File`	`createDirectory(String root, String namePrefix)` Create a directory inside the given parent directory.
`static java.io.File`	`createTempDir(String root, String namePrefix)` Create a temporary directory inside the given parent directory.
`static String`	`decodeFileNameInURI(java.net.URI uri)` Get the file name from uri's raw path and decode it.
`static int`	`DEFAULT_DRIVER_MEM_MB()` Define a default value for driver memory here since this value is referenced across the code base and nearly all files already use Utils.scala
`static int`	`DEFAULT_MAX_TO_STRING_FIELDS()` The performance overhead of creating and logging strings for wide schemas can be large.
`static void`	`deleteRecursively(java.io.File file)` Delete a file or directory and its contents recursively.
`static <T> T`	`deserialize(byte[] bytes)` Deserialize an object using Java serialization
`static <T> T`	`deserialize(byte[] bytes, ClassLoader loader)` Deserialize an object using Java serialization and the given ClassLoader
`static long`	`deserializeLongValue(byte[] bytes)` Deserialize a Long value (used for `PythonPartitioner`)
`static void`	`deserializeViaNestedStream(java.io.InputStream is, SerializerInstance ser, scala.Function1<DeserializationStream,scala.runtime.BoxedUnit> f)` Deserialize via nested stream using specific serializer
`static boolean`	`doesDirectoryContainAnyNewFiles(java.io.File dir, long cutoff)` Determines if a directory contains any files newer than cutoff seconds.
`static scala.collection.immutable.Set<String>`	`EMPTY_USER_GROUPS()`
`static org.json4s.JsonAST.JObject`	`emptyJson()` Return an empty JSON object
`static String`	`encodeFileNameToURIRawPath(String fileName)` A file name may contain some invalid URI characters, such as " ".
`static String`	`exceptionString(Throwable e)` Return a nice string representation of the exception.
`static String`	`executeAndGetOutput(scala.collection.Seq<String> command, java.io.File workingDir, scala.collection.Map<String,String> extraEnvironment, boolean redirectStderr)` Execute a command and get its output, throwing an exception if it yields a code other than 0.
`static Process`	`executeCommand(scala.collection.Seq<String> command, java.io.File workingDir, scala.collection.Map<String,String> extraEnvironment, boolean redirectStderr)` Execute a command and return the process running the command.
`static scala.Tuple2<String,Object>`	`extractHostPortFromSparkUrl(String sparkUrl)` Return a pair of host and port extracted from the `sparkUrl`.
`static void`	`fetchFile(String url, java.io.File targetDir, SparkConf conf, org.apache.spark.SecurityManager securityMgr, org.apache.hadoop.conf.Configuration hadoopConf, long timestamp, boolean useCache)` Download a file or directory to target directory.
`static org.apache.spark.util.CallSite`	`getCallSite(scala.Function1<String,Object> skipClass)` When called inside a class in the spark package, returns the name of the user code class (outside the spark package) that called into Spark, as well as which Spark method they called.
`static String[]`	`getConfiguredLocalDirs(SparkConf conf)` Return the configured local directories where Spark can write files.
`static ClassLoader`	`getContextOrSparkClassLoader()` Get the Context ClassLoader on this thread or, if not present, the ClassLoader that loaded Spark.
`static scala.collection.immutable.Set<String>`	`getCurrentUserGroups(SparkConf sparkConf, String username)`
`static String`	`getCurrentUserName()` Returns the current user name.
`static String`	`getDefaultPropertiesFile(scala.collection.Map<String,String> env)` Return the path of the default Spark properties file.
`static int`	`getDynamicAllocationInitialExecutors(SparkConf conf)` Return the initial number of executors for dynamic allocation.
`static long`	`getFileLength(java.io.File file, SparkConf workConf)` Return the file length, if the file is compressed it returns the uncompressed file length.
`static org.apache.hadoop.fs.Path`	`getFilePath(java.io.File dir, String fileName)` Return the absolute path of a file in the given directory.
`static String`	`getFormattedClassName(Object obj)` Return the class name of the given object, removing all dollar signs
`static org.apache.hadoop.fs.FileSystem`	`getHadoopFileSystem(String path, org.apache.hadoop.conf.Configuration conf)` Return a Hadoop FileSystem with the scheme encoded in the given path.
`static org.apache.hadoop.fs.FileSystem`	`getHadoopFileSystem(java.net.URI path, org.apache.hadoop.conf.Configuration conf)` Return a Hadoop FileSystem with the scheme encoded in the given path.
`static <T> long`	`getIteratorSize(scala.collection.Iterator<T> iterator)` Counts the number of elements of an iterator using a while loop rather than calling `TraversableOnce.size()` because it uses a for loop, which is slightly slower in the current version of Scala.
`static <T> scala.collection.Iterator<scala.Tuple2<T,Object>>`	`getIteratorZipWithIndex(scala.collection.Iterator<T> iterator, long startIndex)` Generate a zipWithIndex iterator, avoid index value overflowing problem in scala's zipWithIndex
`static String`	`getLocalDir(SparkConf conf)` Get the path of a temporary directory.
`static long`	`getMaxResultSize(SparkConf conf)`
`static String`	`getProcessName()` Returns the name of this JVM process.
`static scala.collection.Map<String,String>`	`getPropertiesFromFile(String filename)` Load properties present in the given file.
`static ClassLoader`	`getSparkClassLoader()` Get the ClassLoader which loaded Spark.
`static String`	`getSparkOrYarnConfig(SparkConf conf, String key, String default_)` Return the value of a config either through the SparkConf or the Hadoop configuration if this is Yarn mode.
`static scala.Option<String>`	`getStderr(Process process, long timeoutMs)` Return the stderr of a process after waiting for the process to terminate.
`static scala.collection.Map<String,String>`	`getSystemProperties()` Returns the system properties map that is thread-safe to iterator over.
`static org.apache.spark.util.ThreadStackTrace[]`	`getThreadDump()` Return a thread dump of all threads' stacktraces.
`static scala.Option<org.apache.spark.util.ThreadStackTrace>`	`getThreadDumpForThread(long threadId)`
`static String`	`getUsedTimeMs(long startTimeMs)` Return the string to tell how long has passed in milliseconds.
`static scala.collection.Seq<String>`	`getUserJars(SparkConf conf, boolean isShell)` In YARN mode this method returns a union of the jar files pointed by "spark.jars" and the "spark.yarn.dist.jars" properties, while in other modes it returns the jar files pointed by only the "spark.jars" property.
`static void`	`initDaemon(org.slf4j.Logger log)` Utility function that should be called early in `main()` for daemons to set up some common diagnostic state.
`static Object`	`invoke(Class<?> clazz, Object obj, String methodName, scala.collection.Seq<scala.Tuple2<Class<?>,Object>> args)`
`static boolean`	`isBindCollision(Throwable exception)` Return whether the exception is caused by an address-port collision when binding.
`static boolean`	`isDynamicAllocationEnabled(SparkConf conf)` Return whether dynamic allocation is enabled in the given conf.
`static boolean`	`isFatalError(Throwable e)` Returns true if the given exception was fatal.
`static boolean`	`isInDirectory(java.io.File parent, java.io.File child)` Return whether the specified file is a parent directory of the child file.
`static boolean`	`isLocalMaster(SparkConf conf)`
`static boolean`	`isMac()` Whether the underlying operating system is Mac OS X.
`static boolean`	`isSymlink(java.io.File file)` Check to see if file is a symbolic link.
`static boolean`	`isTesting()` Indicates whether Spark is currently running unit tests.
`static boolean`	`isWindows()` Whether the underlying operating system is Windows.
`static scala.Option<org.json4s.JsonAST.JValue>`	`jsonOption(org.json4s.JsonAST.JValue json)` Return an option that translates JNothing to None
`static String`	`libraryPathEnvName()` Return the current system LD_LIBRARY_PATH name
`static String`	`libraryPathEnvPrefix(scala.collection.Seq<String> libraryPaths)` Return the prefix of a command that appends the given library paths to the system-specific library path environment variable.
`static String`	`loadDefaultSparkProperties(SparkConf conf, String filePath)` Load default Spark properties from the given file.
`static String`	`localHostName()` Get the local machine's hostname.
`static String`	`localHostNameForURI()` Get the local machine's URI.
`static <T> T`	`logUncaughtExceptions(scala.Function0<T> f)` Execute the given block, logging and re-throwing any uncaught exception.
`static String`	`megabytesToString(long megabytes)` Convert a quantity in megabytes to a human-readable string such as "4.0 MB".
`static int`	`memoryStringToMb(String str)` Convert a Java memory parameter passed to -Xmx (such as 300m or 1g) to a number of mebibytes.
`static String`	`msDurationToString(long ms)` Returns a human-readable string representing a duration such as "35ms"
`static int`	`nanSafeCompareDoubles(double x, double y)` NaN-safe version of `java.lang.Double.compare()` which allows NaN values to be compared according to semantics where NaN == NaN and NaN is greater than any non-NaN double.
`static int`	`nanSafeCompareFloats(float x, float y)` NaN-safe version of `java.lang.Float.compare()` which allows NaN values to be compared according to semantics where NaN == NaN and NaN is greater than any non-NaN float.
`static String[]`	`nonLocalPaths(String paths, boolean testWindows)` Return all non-local paths from a comma-separated list of paths.
`static int`	`nonNegativeHash(Object obj)`
`static int`	`nonNegativeMod(int x, int mod)`
`static String`	`offsetBytes(scala.collection.Seq<java.io.File> files, scala.collection.Seq<Object> fileLengths, long start, long end)` Return a string containing data across a set of files.
`static String`	`offsetBytes(String path, long length, long start, long end)` Return a string containing part of a file from byte 'start' to 'end'.
`static scala.Tuple2<String,Object>`	`parseHostPort(String hostPort)`
`static String[]`	`parseStandaloneMasterUrls(String masterUrls)` Split the comma delimited string of master URLs into a list.
`static int`	`portMaxRetries(SparkConf conf)` Maximum number of retries when binding to a port before giving up.
`static Thread`	`processStreamByLine(String threadName, java.io.InputStream inputStream, scala.Function1<String,scala.runtime.BoxedUnit> processLine)` Return and start a daemon thread that processes the content of the input stream line by line.
`static java.util.Random`	`random()`
`static <T> scala.collection.Seq<T>`	`randomize(scala.collection.TraversableOnce<T> seq, scala.reflect.ClassTag<T> evidence$1)` Shuffle the elements of a collection into a random order, returning the result in a new collection.
`static <T> Object`	`randomizeInPlace(Object arr, java.util.Random rand)` Shuffle the elements of an array into a random order, modifying the original array.
`static java.net.URI`	`resolveURI(String path)` Return a well-formed URI for the file described by a user input string.
`static String`	`resolveURIs(String paths)` Resolve a comma-separated list of paths.
`static boolean`	`responseFromBackup(String msg)` Return true if the response message is sent from a backup Master on standby.
`static <T> byte[]`	`serialize(T o)` Serialize an object using Java serialization
`static void`	`serializeViaNestedStream(java.io.OutputStream os, SerializerInstance ser, scala.Function1<SerializationStream,scala.runtime.BoxedUnit> f)` Serialize via nested stream using specific serializer
`static void`	`setCustomHostname(String hostname)` Allow setting a custom host name because when we run on Mesos we need to use the same hostname it reports to the master.
`static void`	`setLogLevel(org.apache.log4j.Level l)` configure a new log4j level
`static java.net.URLConnection`	`setupSecureURLConnection(java.net.URLConnection urlConnection, org.apache.spark.SecurityManager sm)` If the given URL connection is HttpsURLConnection, it sets the SSL socket factory and the host verifier from the given security manager.
`static scala.collection.Seq<String>`	`sparkJavaOpts(SparkConf conf, scala.Function1<String,Object> filterKey)` Convert all spark properties set in the given SparkConf to a sequence of java options.
`static scala.collection.Seq<String>`	`splitCommandString(String s)` Split a string of potentially quoted arguments from the command line the way that a shell would do it to determine arguments to a command.
`static <T> scala.Tuple2<T,Object>`	`startServiceOnPort(int startPort, scala.Function1<Object,scala.Tuple2<T,Object>> startService, SparkConf conf, String serviceName)` Attempt to start a service on the given port, or fail after a number of attempts.
`static String`	`stripDirectory(String path)` Strip the directory from a path name
`static void`	`symlink(java.io.File src, java.io.File dst)` Creates a symlink.
`static java.io.File`	`tempFileWith(java.io.File path)` Returns a path of temporary file which is in the same directory with `path`.
`static scala.Option<Object>`	`terminateProcess(Process process, long timeoutMs)` Terminates a process waiting for at most the specified duration.
`static long`	`timeIt(int numIters, scala.Function0<scala.runtime.BoxedUnit> f, scala.Option<scala.Function0<scala.runtime.BoxedUnit>> prepare)` Timing method based on iterations that permit JVM JIT optimization.
`static void`	`times(int numIters, scala.Function0<scala.runtime.BoxedUnit> f)` Method executed for repeating a task for side effects.
`static long`	`timeStringAsMs(String str)` Convert a time parameter such as (50s, 100ms, or 250us) to microseconds for internal use.
`static long`	`timeStringAsSeconds(String str)` Convert a time parameter such as (50s, 100ms, or 250us) to seconds for internal use.
`static <T> String`	`truncatedString(scala.collection.Seq<T> seq, String sep)` Shorthand for calling truncatedString() without start or end strings.
`static <T> String`	`truncatedString(scala.collection.Seq<T> seq, String start, String sep, String end, int maxNumFields)` Format a sequence with semantics similar to calling .mkString().
`static <T> scala.util.Try<T>`	`tryLog(scala.Function0<T> f)` Executes the given block in a Try, logging any uncaught exceptions.
`static void`	`tryLogNonFatalError(scala.Function0<scala.runtime.BoxedUnit> block)` Executes the given block.
`static void`	`tryOrExit(scala.Function0<scala.runtime.BoxedUnit> block)` Execute a block of code that evaluates to Unit, forwarding any uncaught exceptions to the default UncaughtExceptionHandler
`static <T> T`	`tryOrIOException(scala.Function0<T> block)` Execute a block of code that returns a value, re-throwing any non-fatal uncaught exceptions as IOException.
`static void`	`tryOrStopSparkContext(SparkContext sc, scala.Function0<scala.runtime.BoxedUnit> block)` Execute a block of code that evaluates to Unit, stop SparkContext if there is any uncaught exception
`static <R extends java.io.Closeable,T> T`	`tryWithResource(scala.Function0<R> createResource, scala.Function1<R,T> f)`
`static <T> T`	`tryWithSafeFinally(scala.Function0<T> block, scala.Function0<scala.runtime.BoxedUnit> finallyBlock)` Execute a block of code, then a finally block, but if exceptions happen in the finally block, do not suppress the original exception.
`static <T> T`	`tryWithSafeFinallyAndFailureCallbacks(scala.Function0<T> block, scala.Function0<scala.runtime.BoxedUnit> catchBlock, scala.Function0<scala.runtime.BoxedUnit> finallyBlock)` Execute a block of code and call the failure callbacks in the catch block.
`static scala.collection.immutable.Set<String>`	`unionFileLists(scala.Option<String> leftList, scala.Option<String> rightList)` Unions two comma-separated lists of files and filters out empty strings.
`static void`	`validateURL(java.net.URI uri)` Validate that a given URI is actually a valid URL as well.
`static boolean`	`waitForProcess(Process process, long timeoutMs)` Wait for a process to terminate for at most the specified duration.
`static scala.util.matching.Regex`	`windowsDrive()` Pattern for matching a Windows drive, which contains only a single alphabet character.
`static <T> T`	`withDummyCallSite(SparkContext sc, scala.Function0<T> body)` To avoid calling `Utils.getCallSite` for every single RDD we create in the body, set a dummy call site that RDDs use instead.
`static void`	`writeByteBuffer(java.nio.ByteBuffer bb, java.io.DataOutput out)` Primitive often used when writing `ByteBuffer` to `DataOutput`
`static void`	`writeByteBuffer(java.nio.ByteBuffer bb, java.io.OutputStream out)` Primitive often used when writing `ByteBuffer` to `OutputStream`

Methods inherited from class Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - Utils
```
public Utils()
```
- Method Detail
  - random
```
public static java.util.Random random()
```
  - DEFAULT_DRIVER_MEM_MB
```
public static int DEFAULT_DRIVER_MEM_MB()
```
    Define a default value for driver memory here since this value is referenced across the code base and nearly all files already use Utils.scala
    
    Returns:
    (undocumented)
  - DEFAULT_MAX_TO_STRING_FIELDS
```
public static int DEFAULT_MAX_TO_STRING_FIELDS()
```
    The performance overhead of creating and logging strings for wide schemas can be large. To limit the impact, we bound the number of fields to include by default. This can be overridden by setting the 'spark.debug.maxToStringFields' conf in SparkEnv.
    
    Returns:
    (undocumented)
  - truncatedString
```
public static <T> String truncatedString(scala.collection.Seq<T> seq,
                         String start,
                         String sep,
                         String end,
                         int maxNumFields)
```
    Format a sequence with semantics similar to calling .mkString(). Any elements beyond maxNumToStringFields will be dropped and replaced by a "... N more fields" placeholder.
    
    Parameters:
    seq - (undocumented)
    start - (undocumented)
    sep - (undocumented)
    end - (undocumented)
    maxNumFields - (undocumented)
    
    Returns:
    the trimmed and formatted string.
  - truncatedString
```
public static <T> String truncatedString(scala.collection.Seq<T> seq,
                         String sep)
```
    Shorthand for calling truncatedString() without start or end strings.
  - serialize
```
public static <T> byte[] serialize(T o)
```
    Serialize an object using Java serialization
  - deserialize
```
public static <T> T deserialize(byte[] bytes)
```
    Deserialize an object using Java serialization
  - deserialize
```
public static <T> T deserialize(byte[] bytes,
                ClassLoader loader)
```
    Deserialize an object using Java serialization and the given ClassLoader
  - deserializeLongValue
```
public static long deserializeLongValue(byte[] bytes)
```
    Deserialize a Long value (used for PythonPartitioner)
  - serializeViaNestedStream
```
public static void serializeViaNestedStream(java.io.OutputStream os,
                            SerializerInstance ser,
                            scala.Function1<SerializationStream,scala.runtime.BoxedUnit> f)
```
    Serialize via nested stream using specific serializer
  - deserializeViaNestedStream
```
public static void deserializeViaNestedStream(java.io.InputStream is,
                              SerializerInstance ser,
                              scala.Function1<DeserializationStream,scala.runtime.BoxedUnit> f)
```
    Deserialize via nested stream using specific serializer
  - getSparkClassLoader
```
public static ClassLoader getSparkClassLoader()
```
    Get the ClassLoader which loaded Spark.
    
    Returns:
    (undocumented)
  - getContextOrSparkClassLoader
```
public static ClassLoader getContextOrSparkClassLoader()
```
    Get the Context ClassLoader on this thread or, if not present, the ClassLoader that loaded Spark.
    This should be used whenever passing a ClassLoader to Class.ForName or finding the currently active loader when setting up ClassLoader delegation chains.
    
    Returns:
    (undocumented)
  - classIsLoadable
```
public static boolean classIsLoadable(String clazz)
```
    Determines whether the provided class is loadable in the current thread.
  - classForName
```
public static Class<?> classForName(String className)
```
    Preferred alternative to Class.forName(className)
  - writeByteBuffer
```
public static void writeByteBuffer(java.nio.ByteBuffer bb,
                   java.io.DataOutput out)
```
    Primitive often used when writing ByteBuffer to DataOutput
    
    Parameters:
    bb - (undocumented)
    out - (undocumented)
  - writeByteBuffer
```
public static void writeByteBuffer(java.nio.ByteBuffer bb,
                   java.io.OutputStream out)
```
    Primitive often used when writing ByteBuffer to OutputStream
    
    Parameters:
    bb - (undocumented)
    out - (undocumented)
  - chmod700
```
public static boolean chmod700(java.io.File file)
```
    JDK equivalent of chmod 700 file.
    
    Parameters:
    file - the file whose permissions will be modified
    
    Returns:
    true if the permissions were successfully changed, false otherwise.
  - createDirectory
```
public static java.io.File createDirectory(String root,
                           String namePrefix)
```
    Create a directory inside the given parent directory. The directory is guaranteed to be newly created, and is not marked for automatic deletion.
    
    Parameters:
    root - (undocumented)
    namePrefix - (undocumented)
    
    Returns:
    (undocumented)
  - createTempDir
```
public static java.io.File createTempDir(String root,
                         String namePrefix)
```
    Create a temporary directory inside the given parent directory. The directory will be automatically deleted when the VM shuts down.
    
    Parameters:
    root - (undocumented)
    namePrefix - (undocumented)
    
    Returns:
    (undocumented)
  - copyStream
```
public static long copyStream(java.io.InputStream in,
              java.io.OutputStream out,
              boolean closeStreams,
              boolean transferToEnabled)
```
    Copy all data from an InputStream to an OutputStream. NIO way of file stream to file stream copying is disabled by default unless explicitly set transferToEnabled as true, the parameter transferToEnabled should be configured by spark.file.transferTo = [true|false].
    
    Parameters:
    in - (undocumented)
    out - (undocumented)
    closeStreams - (undocumented)
    transferToEnabled - (undocumented)
    
    Returns:
    (undocumented)
  - constructURIForAuthentication
```
public static java.net.URI constructURIForAuthentication(java.net.URI uri,
                                         org.apache.spark.SecurityManager securityMgr)
```
    Construct a URI container information used for authentication. This also sets the default authenticator to properly negotiation the user/password based on the URI.
    Note this relies on the Authenticator.setDefault being set properly to decode the user name and password. This is currently set in the SecurityManager.
    
    Parameters:
    uri - (undocumented)
    securityMgr - (undocumented)
    
    Returns:
    (undocumented)
  - encodeFileNameToURIRawPath
```
public static String encodeFileNameToURIRawPath(String fileName)
```
    A file name may contain some invalid URI characters, such as " ". This method will convert the file name to a raw path accepted by java.net.URI(String).
    Note: the file name must not contain "/" or "\"
    
    Parameters:
    fileName - (undocumented)
    
    Returns:
    (undocumented)
  - decodeFileNameInURI
```
public static String decodeFileNameInURI(java.net.URI uri)
```
    Get the file name from uri's raw path and decode it. If the raw path of uri ends with "/", return the name before the last "/".
    
    Parameters:
    uri - (undocumented)
    
    Returns:
    (undocumented)
  - fetchFile
```
public static void fetchFile(String url,
             java.io.File targetDir,
             SparkConf conf,
             org.apache.spark.SecurityManager securityMgr,
             org.apache.hadoop.conf.Configuration hadoopConf,
             long timestamp,
             boolean useCache)
```
    Download a file or directory to target directory. Supports fetching the file in a variety of ways, including HTTP, Hadoop-compatible filesystems, and files on a standard filesystem, based on the URL parameter. Fetching directories is only supported from Hadoop-compatible filesystems.
    If useCache is true, first attempts to fetch the file to a local cache that's shared across executors running the same application. useCache is used mainly for the executors, and not in local mode.
    Throws SparkException if the target file already exists and has different contents than the requested file.
    
    Parameters:
    url - (undocumented)
    targetDir - (undocumented)
    conf - (undocumented)
    securityMgr - (undocumented)
    hadoopConf - (undocumented)
    timestamp - (undocumented)
    useCache - (undocumented)
  - validateURL
```
public static void validateURL(java.net.URI uri)
                        throws java.net.MalformedURLException
```
    Validate that a given URI is actually a valid URL as well.
    
    Parameters:
    uri - The URI to validate
    
    Throws:
    
    java.net.MalformedURLException
  - getLocalDir
```
public static String getLocalDir(SparkConf conf)
```
    Get the path of a temporary directory. Spark's local directories can be configured through multiple settings, which are used with the following precedence:
    - If called from inside of a YARN container, this will return a directory chosen by YARN. - If the SPARK_LOCAL_DIRS environment variable is set, this will return a directory from it. - Otherwise, if the spark.local.dir is set, this will return a directory from it. - Otherwise, this will return java.io.tmpdir.
    Some of these configuration options might be lists of multiple paths, but this method will always return a single directory.
    
    Parameters:
    conf - (undocumented)
    
    Returns:
    (undocumented)
  - getConfiguredLocalDirs
```
public static String[] getConfiguredLocalDirs(SparkConf conf)
```
    Return the configured local directories where Spark can write files. This method does not create any directories on its own, it only encapsulates the logic of locating the local directories according to deployment mode.
    
    Parameters:
    conf - (undocumented)
    
    Returns:
    (undocumented)
  - randomize
```
public static <T> scala.collection.Seq<T> randomize(scala.collection.TraversableOnce<T> seq,
                                    scala.reflect.ClassTag<T> evidence$1)
```
    Shuffle the elements of a collection into a random order, returning the result in a new collection. Unlike scala.util.Random.shuffle, this method uses a local random number generator, avoiding inter-thread contention.
    
    Parameters:
    seq - (undocumented)
    evidence$1 - (undocumented)
    
    Returns:
    (undocumented)
  - randomizeInPlace
```
public static <T> Object randomizeInPlace(Object arr,
                          java.util.Random rand)
```
    Shuffle the elements of an array into a random order, modifying the original array. Returns the original array.
    
    Parameters:
    arr - (undocumented)
    rand - (undocumented)
    
    Returns:
    (undocumented)
  - setCustomHostname
```
public static void setCustomHostname(String hostname)
```
    Allow setting a custom host name because when we run on Mesos we need to use the same hostname it reports to the master.
    
    Parameters:
    hostname - (undocumented)
  - localHostName
```
public static String localHostName()
```
    Get the local machine's hostname.
    
    Returns:
    (undocumented)
  - localHostNameForURI
```
public static String localHostNameForURI()
```
    Get the local machine's URI.
    
    Returns:
    (undocumented)
  - checkHost
```
public static void checkHost(String host,
             String message)
```
  - checkHostPort
```
public static void checkHostPort(String hostPort,
                 String message)
```
  - parseHostPort
```
public static scala.Tuple2<String,Object> parseHostPort(String hostPort)
```
  - getUsedTimeMs
```
public static String getUsedTimeMs(long startTimeMs)
```
    Return the string to tell how long has passed in milliseconds.
    
    Parameters:
    startTimeMs - (undocumented)
    
    Returns:
    (undocumented)
  - deleteRecursively
```
public static void deleteRecursively(java.io.File file)
```
    Delete a file or directory and its contents recursively. Don't follow directories if they are symlinks. Throws an exception if deletion is unsuccessful.
    
    Parameters:
    file - (undocumented)
  - isSymlink
```
public static boolean isSymlink(java.io.File file)
```
    Check to see if file is a symbolic link.
    
    Parameters:
    file - (undocumented)
    
    Returns:
    (undocumented)
  - doesDirectoryContainAnyNewFiles
```
public static boolean doesDirectoryContainAnyNewFiles(java.io.File dir,
                                      long cutoff)
```
    Determines if a directory contains any files newer than cutoff seconds.
    
    Parameters:
    dir - must be the path to a directory, or IllegalArgumentException is thrown
    cutoff - measured in seconds. Returns true if there are any files or directories in the given directory whose last modified time is later than this many seconds ago
    
    Returns:
    (undocumented)
  - timeStringAsMs
```
public static long timeStringAsMs(String str)
```
    Convert a time parameter such as (50s, 100ms, or 250us) to microseconds for internal use. If no suffix is provided, the passed number is assumed to be in ms.
    
    Parameters:
    str - (undocumented)
    
    Returns:
    (undocumented)
  - timeStringAsSeconds
```
public static long timeStringAsSeconds(String str)
```
    Convert a time parameter such as (50s, 100ms, or 250us) to seconds for internal use. If no suffix is provided, the passed number is assumed to be in seconds.
    
    Parameters:
    str - (undocumented)
    
    Returns:
    (undocumented)
  - byteStringAsBytes
```
public static long byteStringAsBytes(String str)
```
    Convert a passed byte string (e.g. 50b, 100k, or 250m) to bytes for internal use.
    If no suffix is provided, the passed number is assumed to be in bytes.
    
    Parameters:
    str - (undocumented)
    
    Returns:
    (undocumented)
  - byteStringAsKb
```
public static long byteStringAsKb(String str)
```
    Convert a passed byte string (e.g. 50b, 100k, or 250m) to kibibytes for internal use.
    If no suffix is provided, the passed number is assumed to be in kibibytes.
    
    Parameters:
    str - (undocumented)
    
    Returns:
    (undocumented)
  - byteStringAsMb
```
public static long byteStringAsMb(String str)
```
    Convert a passed byte string (e.g. 50b, 100k, or 250m) to mebibytes for internal use.
    If no suffix is provided, the passed number is assumed to be in mebibytes.
    
    Parameters:
    str - (undocumented)
    
    Returns:
    (undocumented)
  - byteStringAsGb
```
public static long byteStringAsGb(String str)
```
    Convert a passed byte string (e.g. 50b, 100k, or 250m, 500g) to gibibytes for internal use.
    If no suffix is provided, the passed number is assumed to be in gibibytes.
    
    Parameters:
    str - (undocumented)
    
    Returns:
    (undocumented)
  - memoryStringToMb
```
public static int memoryStringToMb(String str)
```
    Convert a Java memory parameter passed to -Xmx (such as 300m or 1g) to a number of mebibytes.
    
    Parameters:
    str - (undocumented)
    
    Returns:
    (undocumented)
  - bytesToString
```
public static String bytesToString(long size)
```
    Convert a quantity in bytes to a human-readable string such as "4.0 MB".
    
    Parameters:
    size - (undocumented)
    
    Returns:
    (undocumented)
  - msDurationToString
```
public static String msDurationToString(long ms)
```
    Returns a human-readable string representing a duration such as "35ms"
    
    Parameters:
    ms - (undocumented)
    
    Returns:
    (undocumented)
  - megabytesToString
```
public static String megabytesToString(long megabytes)
```
    Convert a quantity in megabytes to a human-readable string such as "4.0 MB".
    
    Parameters:
    megabytes - (undocumented)
    
    Returns:
    (undocumented)
  - executeCommand
```
public static Process executeCommand(scala.collection.Seq<String> command,
                     java.io.File workingDir,
                     scala.collection.Map<String,String> extraEnvironment,
                     boolean redirectStderr)
```
    Execute a command and return the process running the command.
    
    Parameters:
    command - (undocumented)
    workingDir - (undocumented)
    extraEnvironment - (undocumented)
    redirectStderr - (undocumented)
    
    Returns:
    (undocumented)
  - executeAndGetOutput
```
public static String executeAndGetOutput(scala.collection.Seq<String> command,
                         java.io.File workingDir,
                         scala.collection.Map<String,String> extraEnvironment,
                         boolean redirectStderr)
```
    Execute a command and get its output, throwing an exception if it yields a code other than 0.
    
    Parameters:
    command - (undocumented)
    workingDir - (undocumented)
    extraEnvironment - (undocumented)
    redirectStderr - (undocumented)
    
    Returns:
    (undocumented)
  - processStreamByLine
```
public static Thread processStreamByLine(String threadName,
                         java.io.InputStream inputStream,
                         scala.Function1<String,scala.runtime.BoxedUnit> processLine)
```
    Return and start a daemon thread that processes the content of the input stream line by line.
    
    Parameters:
    threadName - (undocumented)
    inputStream - (undocumented)
    processLine - (undocumented)
    
    Returns:
    (undocumented)
  - tryOrExit
```
public static void tryOrExit(scala.Function0<scala.runtime.BoxedUnit> block)
```
    Execute a block of code that evaluates to Unit, forwarding any uncaught exceptions to the default UncaughtExceptionHandler
    NOTE: This method is to be called by the spark-started JVM process.
    
    Parameters:
    block - (undocumented)
  - tryOrStopSparkContext
```
public static void tryOrStopSparkContext(SparkContext sc,
                         scala.Function0<scala.runtime.BoxedUnit> block)
```
    Execute a block of code that evaluates to Unit, stop SparkContext if there is any uncaught exception
    NOTE: This method is to be called by the driver-side components to avoid stopping the user-started JVM process completely; in contrast, tryOrExit is to be called in the spark-started JVM process .
    
    Parameters:
    sc - (undocumented)
    block - (undocumented)
  - tryOrIOException
```
public static <T> T tryOrIOException(scala.Function0<T> block)
```
    Execute a block of code that returns a value, re-throwing any non-fatal uncaught exceptions as IOException. This is used when implementing Externalizable and Serializable's read and write methods, since Java's serializer will not report non-IOExceptions properly; see SPARK-4080 for more context.
    
    Parameters:
    block - (undocumented)
    
    Returns:
    (undocumented)
  - tryLogNonFatalError
```
public static void tryLogNonFatalError(scala.Function0<scala.runtime.BoxedUnit> block)
```
    Executes the given block. Log non-fatal errors if any, and only throw fatal errors
  - tryWithSafeFinally
```
public static <T> T tryWithSafeFinally(scala.Function0<T> block,
                       scala.Function0<scala.runtime.BoxedUnit> finallyBlock)
```
    Execute a block of code, then a finally block, but if exceptions happen in the finally block, do not suppress the original exception.
    This is primarily an issue with finally { out.close() } blocks, where close needs to be called to clean up out, but if an exception happened in out.write, it's likely out may be corrupted and out.close will fail as well. This would then suppress the original/likely more meaningful exception from the original out.write call.
    
    Parameters:
    block - (undocumented)
    finallyBlock - (undocumented)
    
    Returns:
    (undocumented)
  - tryWithSafeFinallyAndFailureCallbacks
```
public static <T> T tryWithSafeFinallyAndFailureCallbacks(scala.Function0<T> block,
                                          scala.Function0<scala.runtime.BoxedUnit> catchBlock,
                                          scala.Function0<scala.runtime.BoxedUnit> finallyBlock)
```
    Execute a block of code and call the failure callbacks in the catch block. If exceptions occur in either the catch or the finally block, they are appended to the list of suppressed exceptions in original exception which is then rethrown.
    This is primarily an issue with catch { abort() } or finally { out.close() } blocks, where the abort/close needs to be called to clean up out, but if an exception happened in out.write, it's likely out may be corrupted and abort or out.close will fail as well. This would then suppress the original/likely more meaningful exception from the original out.write call.
    
    Parameters:
    block - (undocumented)
    catchBlock - (undocumented)
    finallyBlock - (undocumented)
    
    Returns:
    (undocumented)
  - getCallSite
```
public static org.apache.spark.util.CallSite getCallSite(scala.Function1<String,Object> skipClass)
```
    When called inside a class in the spark package, returns the name of the user code class (outside the spark package) that called into Spark, as well as which Spark method they called. This is used, for example, to tell users where in their code each RDD got created.
    
    Parameters:
    skipClass - Function that is used to exclude non-user-code classes.
    
    Returns:
    (undocumented)
  - getFileLength
```
public static long getFileLength(java.io.File file,
                 SparkConf workConf)
```
    Return the file length, if the file is compressed it returns the uncompressed file length. It also caches the uncompressed file size to avoid repeated decompression. The cache size is read from workerConf.
    
    Parameters:
    file - (undocumented)
    workConf - (undocumented)
    
    Returns:
    (undocumented)
  - offsetBytes
```
public static String offsetBytes(String path,
                 long length,
                 long start,
                 long end)
```
    Return a string containing part of a file from byte 'start' to 'end'.
  - offsetBytes
```
public static String offsetBytes(scala.collection.Seq<java.io.File> files,
                 scala.collection.Seq<Object> fileLengths,
                 long start,
                 long end)
```
    Return a string containing data across a set of files. The startIndex and endIndex is based on the cumulative size of all the files take in the given order. See figure below for more details.
    
    Parameters:
    files - (undocumented)
    fileLengths - (undocumented)
    start - (undocumented)
    end - (undocumented)
    
    Returns:
    (undocumented)
  - clone
```
public static <T> T clone(T value,
          SerializerInstance serializer,
          scala.reflect.ClassTag<T> evidence$2)
```
    Clone an object using a Spark serializer.
    
    Parameters:
    value - (undocumented)
    serializer - (undocumented)
    evidence$2 - (undocumented)
    
    Returns:
    (undocumented)
  - splitCommandString
```
public static scala.collection.Seq<String> splitCommandString(String s)
```
    Split a string of potentially quoted arguments from the command line the way that a shell would do it to determine arguments to a command. For example, if the string is 'a "b c" d', then it would be parsed as three arguments: 'a', 'b c' and 'd'.
    
    Parameters:
    s - (undocumented)
    
    Returns:
    (undocumented)
  - nonNegativeMod
```
public static int nonNegativeMod(int x,
                 int mod)
```
  - nonNegativeHash
```
public static int nonNegativeHash(Object obj)
```
  - nanSafeCompareDoubles
```
public static int nanSafeCompareDoubles(double x,
                        double y)
```
    NaN-safe version of java.lang.Double.compare() which allows NaN values to be compared according to semantics where NaN == NaN and NaN is greater than any non-NaN double.
    
    Parameters:
    x - (undocumented)
    y - (undocumented)
    
    Returns:
    (undocumented)
  - nanSafeCompareFloats
```
public static int nanSafeCompareFloats(float x,
                       float y)
```
    NaN-safe version of java.lang.Float.compare() which allows NaN values to be compared according to semantics where NaN == NaN and NaN is greater than any non-NaN float.
    
    Parameters:
    x - (undocumented)
    y - (undocumented)
    
    Returns:
    (undocumented)
  - getSystemProperties
```
public static scala.collection.Map<String,String> getSystemProperties()
```
    Returns the system properties map that is thread-safe to iterator over. It gets the properties which have been set explicitly, as well as those for which only a default value has been defined.
    
    Returns:
    (undocumented)
  - times
```
public static void times(int numIters,
         scala.Function0<scala.runtime.BoxedUnit> f)
```
    Method executed for repeating a task for side effects. Unlike a for comprehension, it permits JVM JIT optimization
    
    Parameters:
    numIters - (undocumented)
    f - (undocumented)
  - timeIt
```
public static long timeIt(int numIters,
          scala.Function0<scala.runtime.BoxedUnit> f,
          scala.Option<scala.Function0<scala.runtime.BoxedUnit>> prepare)
```
    Timing method based on iterations that permit JVM JIT optimization.
    
    Parameters:
    numIters - number of iterations
    f - function to be executed. If prepare is not None, the running time of each call to f must be an order of magnitude longer than one millisecond for accurate timing.
    prepare - function to be executed before each call to f. Its running time doesn't count.
    
    Returns:
    the total time across all iterations (not counting preparation time)
  - getIteratorSize
```
public static <T> long getIteratorSize(scala.collection.Iterator<T> iterator)
```
    Counts the number of elements of an iterator using a while loop rather than calling TraversableOnce.size() because it uses a for loop, which is slightly slower in the current version of Scala.
    
    Parameters:
    iterator - (undocumented)
    
    Returns:
    (undocumented)
  - getIteratorZipWithIndex
```
public static <T> scala.collection.Iterator<scala.Tuple2<T,Object>> getIteratorZipWithIndex(scala.collection.Iterator<T> iterator,
                                                                            long startIndex)
```
    Generate a zipWithIndex iterator, avoid index value overflowing problem in scala's zipWithIndex
    
    Parameters:
    iterator - (undocumented)
    startIndex - (undocumented)
    
    Returns:
    (undocumented)
  - symlink
```
public static void symlink(java.io.File src,
           java.io.File dst)
```
    Creates a symlink.
    
    Parameters:
    src - absolute path to the source
    dst - relative path for the destination
  - getFormattedClassName
```
public static String getFormattedClassName(Object obj)
```
    Return the class name of the given object, removing all dollar signs
  - jsonOption
```
public static scala.Option<org.json4s.JsonAST.JValue> jsonOption(org.json4s.JsonAST.JValue json)
```
    Return an option that translates JNothing to None
  - emptyJson
```
public static org.json4s.JsonAST.JObject emptyJson()
```
    Return an empty JSON object
  - getHadoopFileSystem
```
public static org.apache.hadoop.fs.FileSystem getHadoopFileSystem(java.net.URI path,
                                                  org.apache.hadoop.conf.Configuration conf)
```
    Return a Hadoop FileSystem with the scheme encoded in the given path.
    
    Parameters:
    path - (undocumented)
    conf - (undocumented)
    
    Returns:
    (undocumented)
  - getHadoopFileSystem
```
public static org.apache.hadoop.fs.FileSystem getHadoopFileSystem(String path,
                                                  org.apache.hadoop.conf.Configuration conf)
```
    Return a Hadoop FileSystem with the scheme encoded in the given path.
    
    Parameters:
    path - (undocumented)
    conf - (undocumented)
    
    Returns:
    (undocumented)
  - getFilePath
```
public static org.apache.hadoop.fs.Path getFilePath(java.io.File dir,
                                    String fileName)
```
    Return the absolute path of a file in the given directory.
    
    Parameters:
    dir - (undocumented)
    fileName - (undocumented)
    
    Returns:
    (undocumented)
  - isWindows
```
public static boolean isWindows()
```
    Whether the underlying operating system is Windows.
    
    Returns:
    (undocumented)
  - isMac
```
public static boolean isMac()
```
    Whether the underlying operating system is Mac OS X.
    
    Returns:
    (undocumented)
  - windowsDrive
```
public static scala.util.matching.Regex windowsDrive()
```
    Pattern for matching a Windows drive, which contains only a single alphabet character.
    
    Returns:
    (undocumented)
  - isTesting
```
public static boolean isTesting()
```
    Indicates whether Spark is currently running unit tests.
    
    Returns:
    (undocumented)
  - stripDirectory
```
public static String stripDirectory(String path)
```
    Strip the directory from a path name
    
    Parameters:
    path - (undocumented)
    
    Returns:
    (undocumented)
  - terminateProcess
```
public static scala.Option<Object> terminateProcess(Process process,
                                    long timeoutMs)
```
    Terminates a process waiting for at most the specified duration.
    
    Parameters:
    process - (undocumented)
    timeoutMs - (undocumented)
    
    Returns:
    the process exit value if it was successfully terminated, else None
  - waitForProcess
```
public static boolean waitForProcess(Process process,
                     long timeoutMs)
```
    Wait for a process to terminate for at most the specified duration.
    
    Parameters:
    process - (undocumented)
    timeoutMs - (undocumented)
    
    Returns:
    whether the process actually terminated before the given timeout.
  - getStderr
```
public static scala.Option<String> getStderr(Process process,
                             long timeoutMs)
```
    Return the stderr of a process after waiting for the process to terminate. If the process does not terminate within the specified timeout, return None.
    
    Parameters:
    process - (undocumented)
    timeoutMs - (undocumented)
    
    Returns:
    (undocumented)
  - logUncaughtExceptions
```
public static <T> T logUncaughtExceptions(scala.Function0<T> f)
```
    Execute the given block, logging and re-throwing any uncaught exception. This is particularly useful for wrapping code that runs in a thread, to ensure that exceptions are printed, and to avoid having to catch Throwable.
    
    Parameters:
    f - (undocumented)
    
    Returns:
    (undocumented)
  - tryLog
```
public static <T> scala.util.Try<T> tryLog(scala.Function0<T> f)
```
    Executes the given block in a Try, logging any uncaught exceptions.
  - isFatalError
```
public static boolean isFatalError(Throwable e)
```
    Returns true if the given exception was fatal. See docs for scala.util.control.NonFatal.
  - resolveURI
```
public static java.net.URI resolveURI(String path)
```
    Return a well-formed URI for the file described by a user input string.
    If the supplied path does not contain a scheme, or is a relative path, it will be converted into an absolute path with a file:// scheme.
    
    Parameters:
    path - (undocumented)
    
    Returns:
    (undocumented)
  - resolveURIs
```
public static String resolveURIs(String paths)
```
    Resolve a comma-separated list of paths.
  - nonLocalPaths
```
public static String[] nonLocalPaths(String paths,
                     boolean testWindows)
```
    Return all non-local paths from a comma-separated list of paths.
  - loadDefaultSparkProperties
```
public static String loadDefaultSparkProperties(SparkConf conf,
                                String filePath)
```
    Load default Spark properties from the given file. If no file is provided, use the common defaults file. This mutates state in the given SparkConf and in this JVM's system properties if the config specified in the file is not already set. Return the path of the properties file used.
    
    Parameters:
    conf - (undocumented)
    filePath - (undocumented)
    
    Returns:
    (undocumented)
  - getPropertiesFromFile
```
public static scala.collection.Map<String,String> getPropertiesFromFile(String filename)
```
    Load properties present in the given file.
  - getDefaultPropertiesFile
```
public static String getDefaultPropertiesFile(scala.collection.Map<String,String> env)
```
    Return the path of the default Spark properties file.
  - exceptionString
```
public static String exceptionString(Throwable e)
```
    Return a nice string representation of the exception. It will call "printStackTrace" to recursively generate the stack trace including the exception and its causes.
    
    Parameters:
    e - (undocumented)
    
    Returns:
    (undocumented)
  - getThreadDump
```
public static org.apache.spark.util.ThreadStackTrace[] getThreadDump()
```
    Return a thread dump of all threads' stacktraces. Used to capture dumps for the web UI
  - getThreadDumpForThread
```
public static scala.Option<org.apache.spark.util.ThreadStackTrace> getThreadDumpForThread(long threadId)
```
  - sparkJavaOpts
```
public static scala.collection.Seq<String> sparkJavaOpts(SparkConf conf,
                                         scala.Function1<String,Object> filterKey)
```
    Convert all spark properties set in the given SparkConf to a sequence of java options.
    
    Parameters:
    conf - (undocumented)
    filterKey - (undocumented)
    
    Returns:
    (undocumented)
  - portMaxRetries
```
public static int portMaxRetries(SparkConf conf)
```
    Maximum number of retries when binding to a port before giving up.
    
    Parameters:
    conf - (undocumented)
    
    Returns:
    (undocumented)
  - startServiceOnPort
```
public static <T> scala.Tuple2<T,Object> startServiceOnPort(int startPort,
                                            scala.Function1<Object,scala.Tuple2<T,Object>> startService,
                                            SparkConf conf,
                                            String serviceName)
```
    Attempt to start a service on the given port, or fail after a number of attempts. Each subsequent attempt uses 1 + the port used in the previous attempt (unless the port is 0).
    
    Parameters:
    startPort - The initial port to start the service on.
    startService - Function to start service on a given port. This is expected to throw java.net.BindException on port collision.
    conf - A SparkConf used to get the maximum number of retries when binding to a port.
    serviceName - Name of the service.
    
    Returns:
    (service: T, port: Int)
  - isBindCollision
```
public static boolean isBindCollision(Throwable exception)
```
    Return whether the exception is caused by an address-port collision when binding.
    
    Parameters:
    exception - (undocumented)
    
    Returns:
    (undocumented)
  - setLogLevel
```
public static void setLogLevel(org.apache.log4j.Level l)
```
    configure a new log4j level
    
    Parameters:
    l - (undocumented)
  - configTestLog4j
```
public static void configTestLog4j(String level)
```
    config a log4j properties used for testsuite
    
    Parameters:
    level - (undocumented)
  - setupSecureURLConnection
```
public static java.net.URLConnection setupSecureURLConnection(java.net.URLConnection urlConnection,
                                              org.apache.spark.SecurityManager sm)
```
    If the given URL connection is HttpsURLConnection, it sets the SSL socket factory and the host verifier from the given security manager.
    
    Parameters:
    urlConnection - (undocumented)
    sm - (undocumented)
    
    Returns:
    (undocumented)
  - invoke
```
public static Object invoke(Class<?> clazz,
            Object obj,
            String methodName,
            scala.collection.Seq<scala.Tuple2<Class<?>,Object>> args)
```
  - getMaxResultSize
```
public static long getMaxResultSize(SparkConf conf)
```
  - libraryPathEnvName
```
public static String libraryPathEnvName()
```
    Return the current system LD_LIBRARY_PATH name
    
    Returns:
    (undocumented)
  - libraryPathEnvPrefix
```
public static String libraryPathEnvPrefix(scala.collection.Seq<String> libraryPaths)
```
    Return the prefix of a command that appends the given library paths to the system-specific library path environment variable. On Unix, for instance, this returns the string LD_LIBRARY_PATH="path1:path2:$LD_LIBRARY_PATH".
    
    Parameters:
    libraryPaths - (undocumented)
    
    Returns:
    (undocumented)
  - getSparkOrYarnConfig
```
public static String getSparkOrYarnConfig(SparkConf conf,
                          String key,
                          String default_)
```
    Return the value of a config either through the SparkConf or the Hadoop configuration if this is Yarn mode. In the latter case, this defaults to the value set through SparkConf if the key is not set in the Hadoop configuration.
    
    Parameters:
    conf - (undocumented)
    key - (undocumented)
    default_ - (undocumented)
    
    Returns:
    (undocumented)
  - extractHostPortFromSparkUrl
```
public static scala.Tuple2<String,Object> extractHostPortFromSparkUrl(String sparkUrl)
                                                               throws SparkException
```
    Return a pair of host and port extracted from the sparkUrl.
    A spark url (spark://host:port) is a special URI that its scheme is spark and only contains host and port.
    
    Parameters:
    sparkUrl - (undocumented)
    
    Returns:
    (undocumented)
    
    Throws:
    
    SparkException - if sparkUrl is invalid.
  - getCurrentUserName
```
public static String getCurrentUserName()
```
    Returns the current user name. This is the currently logged in user, unless that's been overridden by the SPARK_USER environment variable.
    
    Returns:
    (undocumented)
  - EMPTY_USER_GROUPS
```
public static scala.collection.immutable.Set<String> EMPTY_USER_GROUPS()
```
  - getCurrentUserGroups
```
public static scala.collection.immutable.Set<String> getCurrentUserGroups(SparkConf sparkConf,
                                                          String username)
```
  - parseStandaloneMasterUrls
```
public static String[] parseStandaloneMasterUrls(String masterUrls)
```
    Split the comma delimited string of master URLs into a list. For instance, "spark://abc,def" becomes [spark://abc, spark://def].
    
    Parameters:
    masterUrls - (undocumented)
    
    Returns:
    (undocumented)
  - BACKUP_STANDALONE_MASTER_PREFIX
```
public static String BACKUP_STANDALONE_MASTER_PREFIX()
```
    An identifier that backup masters use in their responses.
  - responseFromBackup
```
public static boolean responseFromBackup(String msg)
```
    Return true if the response message is sent from a backup Master on standby.
  - withDummyCallSite
```
public static <T> T withDummyCallSite(SparkContext sc,
                      scala.Function0<T> body)
```
    To avoid calling Utils.getCallSite for every single RDD we create in the body, set a dummy call site that RDDs use instead. This is for performance optimization.
    
    Parameters:
    sc - (undocumented)
    body - (undocumented)
    
    Returns:
    (undocumented)
  - isInDirectory
```
public static boolean isInDirectory(java.io.File parent,
                    java.io.File child)
```
    Return whether the specified file is a parent directory of the child file.
    
    Parameters:
    parent - (undocumented)
    child - (undocumented)
    
    Returns:
    (undocumented)
  - isLocalMaster
```
public static boolean isLocalMaster(SparkConf conf)
```
    Parameters:
    conf - (undocumented)
    
    Returns:
    whether it is local mode
  - isDynamicAllocationEnabled
```
public static boolean isDynamicAllocationEnabled(SparkConf conf)
```
    Return whether dynamic allocation is enabled in the given conf.
    
    Parameters:
    conf - (undocumented)
    
    Returns:
    (undocumented)
  - getDynamicAllocationInitialExecutors
```
public static int getDynamicAllocationInitialExecutors(SparkConf conf)
```
    Return the initial number of executors for dynamic allocation.
    
    Parameters:
    conf - (undocumented)
    
    Returns:
    (undocumented)
  - tryWithResource
```
public static <R extends java.io.Closeable,T> T tryWithResource(scala.Function0<R> createResource,
                                                scala.Function1<R,T> f)
```
  - tempFileWith
```
public static java.io.File tempFileWith(java.io.File path)
```
    Returns a path of temporary file which is in the same directory with path.
    
    Parameters:
    path - (undocumented)
    
    Returns:
    (undocumented)
  - getProcessName
```
public static String getProcessName()
```
    Returns the name of this JVM process. This is OS dependent but typically (OSX, Linux, Windows), this is formatted as PID@hostname.
    
    Returns:
    (undocumented)
  - initDaemon
```
public static void initDaemon(org.slf4j.Logger log)
```
    Utility function that should be called early in main() for daemons to set up some common diagnostic state.
    
    Parameters:
    log - (undocumented)
  - unionFileLists
```
public static scala.collection.immutable.Set<String> unionFileLists(scala.Option<String> leftList,
                                                    scala.Option<String> rightList)
```
    Unions two comma-separated lists of files and filters out empty strings.
    
    Parameters:
    leftList - (undocumented)
    rightList - (undocumented)
    
    Returns:
    (undocumented)
  - getUserJars
```
public static scala.collection.Seq<String> getUserJars(SparkConf conf,
                                       boolean isShell)
```
    In YARN mode this method returns a union of the jar files pointed by "spark.jars" and the "spark.yarn.dist.jars" properties, while in other modes it returns the jar files pointed by only the "spark.jars" property.
    
    Parameters:
    conf - (undocumented)
    isShell - (undocumented)
    
    Returns:
    (undocumented)

Class Utils

Constructor Summary

Method Summary

Methods inherited from class Object

Constructor Detail

Utils

Method Detail

random

DEFAULT_DRIVER_MEM_MB

DEFAULT_MAX_TO_STRING_FIELDS

truncatedString

truncatedString

serialize

deserialize

deserialize

deserializeLongValue

serializeViaNestedStream

deserializeViaNestedStream

getSparkClassLoader

getContextOrSparkClassLoader

classIsLoadable

classForName

writeByteBuffer

writeByteBuffer

chmod700

createDirectory

createTempDir

copyStream

constructURIForAuthentication

encodeFileNameToURIRawPath

decodeFileNameInURI

fetchFile

validateURL

getLocalDir

getConfiguredLocalDirs

randomize

randomizeInPlace

setCustomHostname

localHostName

localHostNameForURI

checkHost

checkHostPort

parseHostPort

getUsedTimeMs

deleteRecursively

isSymlink

doesDirectoryContainAnyNewFiles

timeStringAsMs

timeStringAsSeconds

byteStringAsBytes

byteStringAsKb

byteStringAsMb

byteStringAsGb

memoryStringToMb

bytesToString

msDurationToString

megabytesToString

executeCommand

executeAndGetOutput

processStreamByLine

tryOrExit

tryOrStopSparkContext

tryOrIOException

tryLogNonFatalError

tryWithSafeFinally

tryWithSafeFinallyAndFailureCallbacks

getCallSite

getFileLength

offsetBytes

offsetBytes

clone

splitCommandString

nonNegativeMod

nonNegativeHash

nanSafeCompareDoubles

nanSafeCompareFloats

getSystemProperties

times

timeIt

getIteratorSize