Package org.apache.lucene.util

Class IOUtils

java.lang.Object
org.apache.lucene.util.IOUtils
public final class IOUtils extends Object
This class emulates the new Java 7 "Try-With-Resources" statement. Remove once Lucene is on Java 7.

  • Field Details

  • Constructor Details

    • IOUtils

      private IOUtils()

  • Method Details

    • close

      public static void close(Closeable... objects) throws IOException
      Closes all given Closeables. Some of the Closeables may be null; they are ignored. After everything is closed, the method either throws the first exception it hit while closing, or completes normally if there were no exceptions.
      Parameters:
      objects - objects to call close() on
      Throws:
      IOException

    • close

      public static void close(Iterable<? extends Closeable> objects) throws IOException
      Closes all given Closeables.
      Throws:
      IOException
      See Also:

    • closeWhileHandlingException

      public static void closeWhileHandlingException(Closeable... objects)
      Closes all given Closeables, suppressing all thrown exceptions. Some of the Closeables may be null, they are ignored.
      Parameters:
      objects - objects to call close() on

    • closeWhileHandlingException

      public static void closeWhileHandlingException(Iterable<? extends Closeable> objects)
      Closes all given Closeables, suppressing all thrown non VirtualMachineError exceptions. Even if a VirtualMachineError is thrown all given closeable are closed.
      See Also:

    • getDecodingReader

      public static Reader getDecodingReader(InputStream stream, Charset charSet)
      Wrapping the given InputStream in a reader using a CharsetDecoder. Unlike Java's defaults this reader will throw an exception if your it detects the read charset doesn't match the expected Charset.

      Decoding readers are useful to load configuration files, stopword lists or synonym files to detect character set problems. However, it's not recommended to use as a common purpose reader.

      Parameters:
      stream - the stream to wrap in a reader
      charSet - the expected charset
      Returns:
      a wrapping reader

    • getDecodingReader

      public static Reader getDecodingReader(Class<?> clazz, String resource, Charset charSet) throws IOException
      Opens a Reader for the given resource using a CharsetDecoder. Unlike Java's defaults this reader will throw an exception if your it detects the read charset doesn't match the expected Charset.

      Decoding readers are useful to load configuration files, stopword lists or synonym files to detect character set problems. However, it's not recommended to use as a common purpose reader.

      Parameters:
      clazz - the class used to locate the resource
      resource - the resource name to load
      charSet - the expected charset
      Returns:
      a reader to read the given file
      Throws:
      IOException

    • deleteFilesIgnoringExceptions

      public static void deleteFilesIgnoringExceptions(Directory dir, Collection<String> files)
      Deletes all given files, suppressing all thrown IOExceptions.

      Note that the files should not be null.

    • deleteFilesIgnoringExceptions

      public static void deleteFilesIgnoringExceptions(Directory dir, String... files)

    • deleteFiles

      public static void deleteFiles(Directory dir, Collection<String> names) throws IOException
      Deletes all given file names. Some of the file names may be null; they are ignored. After everything is deleted, the method either throws the first exception it hit while deleting, or completes normally if there were no exceptions.
      Parameters:
      dir - Directory to delete files from
      names - file names to delete
      Throws:
      IOException

    • deleteFilesIgnoringExceptions

      public static void deleteFilesIgnoringExceptions(Path... files)
      Deletes all given files, suppressing all thrown IOExceptions.

      Some of the files may be null, if so they are ignored.

    • deleteFilesIgnoringExceptions

      public static void deleteFilesIgnoringExceptions(Collection<? extends Path> files)
      Deletes all given files, suppressing all thrown IOExceptions.

      Some of the files may be null, if so they are ignored.

    • deleteFilesIfExist

      public static void deleteFilesIfExist(Path... files) throws IOException
      Deletes all given Paths, if they exist. Some of the Files may be null; they are ignored. After everything is deleted, the method either throws the first exception it hit while deleting, or completes normally if there were no exceptions.
      Parameters:
      files - files to delete
      Throws:
      IOException

    • deleteFilesIfExist

      public static void deleteFilesIfExist(Collection<? extends Path> files) throws IOException
      Deletes all given Paths, if they exist. Some of the Files may be null; they are ignored. After everything is deleted, the method either throws the first exception it hit while deleting, or completes normally if there were no exceptions.
      Parameters:
      files - files to delete
      Throws:
      IOException

    • rm

      public static void rm(Path... locations) throws IOException
      Deletes one or more files or directories (and everything underneath it).
      Throws:
      IOException - if any of the given files (or their subhierarchy files in case of directories) cannot be removed.

    • rm

      private static LinkedHashMap<Path,Throwable> rm(LinkedHashMap<Path,Throwable> unremoved, Path... locations)

    • rethrowAlways

      public static Error rethrowAlways(Throwable th) throws IOException, RuntimeException
      This utility method takes a previously caught (non-null) Throwable and rethrows either the original argument if it was a subclass of the IOException or an RuntimeException with the cause set to the argument.

      This method never returns any value, even though it declares a return value of type Error. The return value declaration is very useful to let the compiler know that the code path following the invocation of this method is unreachable. So in most cases the invocation of this method will be guarded by an if and used together with a throw statement, as in: 

      
   if (t != null) throw IOUtils.rethrowAlways(t)
      Parameters:
      th - The throwable to rethrow, must not be null.
      Returns:
      This method always results in an exception, it never returns any value. See method documentation for detailsa and usage example.
      Throws:
      IOException - if the argument was an instance of IOException
      RuntimeException - with the Throwable.getCause() set to the argument, if it was not an instance of IOException.

    • reThrow

      @Deprecated public static void reThrow(Throwable th) throws IOException
      Deprecated.
      This method is deprecated in favor of rethrowAlways(java.lang.Throwable). Code should be updated to rethrowAlways(java.lang.Throwable) and guarded with an additional null-argument check (because rethrowAlways(java.lang.Throwable) is not accepting null arguments).
      Rethrows the argument as IOException or RuntimeException if it's not null.
      Throws:
      IOException

    • reThrowUnchecked

      @Deprecated public static void reThrowUnchecked(Throwable th)
      Deprecated.
      This method is deprecated in favor of rethrowAlways(java.lang.Throwable). Code should be updated to rethrowAlways(java.lang.Throwable) and guarded with an additional null-argument check (because rethrowAlways(java.lang.Throwable) is not accepting null arguments).

    • fsync

      public static void fsync(Path fileToSync, boolean isDir) throws IOException
      Ensure that any writes to the given file is written to the storage device that contains it.
      Parameters:
      fileToSync - the file to fsync
      isDir - if true, the given file is a directory (we open for read and ignore IOExceptions, because not all file systems and operating systems allow to fsync on a directory)
      Throws:
      IOException

    • spins

      public static boolean spins(Directory dir) throws IOException
      If the dir is an FSDirectory or wraps one via possibly nested FilterDirectory or FileSwitchDirectory, this returns spins(Path) for the wrapped directory, else, true.
      Throws:
      IOException - if path does not exist.

    • spins

      public static boolean spins(Path path) throws IOException
      Rough Linux-only heuristics to determine whether the provided Path is backed by spinning storage. For example, this returns false if the disk is a solid-state disk.
      Parameters:
      path - a location to check which must exist. the mount point will be determined from this location.
      Returns:
      false if the storage is non-rotational (e.g. an SSD), or true if it is spinning or could not be determined
      Throws:
      IOException - if path does not exist.

    • spinsLinux

      static boolean spinsLinux(Path path) throws IOException
      Throws:
      IOException

    • getFileStore

      static FileStore getFileStore(Path path) throws IOException
      Throws:
      IOException

    • getMountPoint

      static String getMountPoint(FileStore store)

    • useOrSuppress

      public static <T extends Throwable> T useOrSuppress(T first, T second)
      Returns the second throwable if the first is null otherwise adds the second as suppressed to the first and returns it.

    • applyToAll

      public static <T> void applyToAll(Collection<T> collection, IOUtils.IOConsumer<T> consumer) throws IOException
      Applies the consumer to all non-null elements in the collection even if an exception is thrown. The first exception thrown by the consumer is re-thrown and subsequent exceptions are suppressed.
      Throws:
      IOException