Package org.apache.lucene.util

Class IOUtils

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

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static java.nio.charset.Charset CHARSET_UTF_8
      UTF-8 Charset instance to prevent repeated Charset.forName(String) lookups
      static java.lang.String UTF_8
      UTF-8 charset string

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static void close​(java.io.Closeable... objects)
      Closes all given Closeables.
      static void close​(java.lang.Iterable<? extends java.io.Closeable> objects)
      Closes all given Closeables.
      static <E extends java.lang.Exception>
      void      		 closeWhileHandlingException​(E priorException, java.io.Closeable... objects)
      Closes all given Closeables, suppressing all thrown exceptions.
      static <E extends java.lang.Exception>
      void      		 closeWhileHandlingException​(E priorException, java.lang.Iterable<? extends java.io.Closeable> objects)
      Closes all given Closeables, suppressing all thrown exceptions.
      static void closeWhileHandlingException​(java.io.Closeable... objects)
      Closes all given Closeables, suppressing all thrown exceptions.
      static void closeWhileHandlingException​(java.lang.Iterable<? extends java.io.Closeable> objects)
      Closes all given Closeables, suppressing all thrown exceptions.
      static void copy​(java.io.File source, java.io.File target)
      Copy one file's contents to another file.
      static void deleteFilesIgnoringExceptions​(Directory dir, java.lang.String... files)
      Deletes all given files, suppressing all thrown IOExceptions.
      static java.io.Reader getDecodingReader​(java.io.File file, java.nio.charset.Charset charSet)
      Opens a Reader for the given File using a CharsetDecoder.
      static java.io.Reader getDecodingReader​(java.io.InputStream stream, java.nio.charset.Charset charSet)
      Wrapping the given InputStream in a reader using a CharsetDecoder.
      static java.io.Reader getDecodingReader​(java.lang.Class<?> clazz, java.lang.String resource, java.nio.charset.Charset charSet)
      Opens a Reader for the given resource using a CharsetDecoder.
      static void reThrow​(java.lang.Throwable th)
      Simple utilty method that takes a previously caught Throwable and rethrows either IOException or an unchecked exception.
      static void reThrowUnchecked​(java.lang.Throwable th)
      Simple utilty method that takes a previously caught Throwable and rethrows it as an unchecked exception.

      • Methods inherited from class java.lang.Object

        equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • UTF_8

        public static final java.lang.String UTF_8
        UTF-8 charset string
        See Also:
        Charset.forName(String), Constant Field Values

      • CHARSET_UTF_8

        public static final java.nio.charset.Charset CHARSET_UTF_8
        UTF-8 Charset instance to prevent repeated Charset.forName(String) lookups

    • Method Detail

      • closeWhileHandlingException

        public static <E extends java.lang.Exception> void closeWhileHandlingException​(E priorException,
                                                                               java.io.Closeable... objects)
                                                                        throws E extends java.lang.Exception,
                                                                               java.io.IOException

        Closes all given Closeables, suppressing all thrown exceptions. Some of the Closeables may be null, they are ignored. After everything is closed, method either throws priorException, if one is supplied, or the first of suppressed exceptions, or completes normally.

        Sample usage:

         Closeable resource1 = null, resource2 = null, resource3 = null;
 ExpectedException priorE = null;
 try {
   resource1 = ...; resource2 = ...; resource3 = ...; // Acquisition may throw ExpectedException
   ..do..stuff.. // May throw ExpectedException
 } catch (ExpectedException e) {
   priorE = e;
 } finally {
   closeWhileHandlingException(priorE, resource1, resource2, resource3);
 }

        Parameters:
        priorException - null or an exception that will be rethrown after method completion
        objects - objects to call close() on
        Throws:
        E extends java.lang.Exception
        java.io.IOException

      • closeWhileHandlingException

        public static <E extends java.lang.Exception> void closeWhileHandlingException​(E priorException,
                                                                               java.lang.Iterable<? extends java.io.Closeable> objects)
                                                                        throws E extends java.lang.Exception,
                                                                               java.io.IOException
        Closes all given Closeables, suppressing all thrown exceptions.
        Throws:
        E extends java.lang.Exception
        java.io.IOException
        See Also:
        closeWhileHandlingException(Exception, Closeable...)

      • close

        public static void close​(java.io.Closeable... objects)
                  throws java.io.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:
        java.io.IOException

      • close

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

      • closeWhileHandlingException

        public static void closeWhileHandlingException​(java.io.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​(java.lang.Iterable<? extends java.io.Closeable> objects)
        Closes all given Closeables, suppressing all thrown exceptions.
        See Also:
        closeWhileHandlingException(Closeable...)

      • getDecodingReader

        public static java.io.Reader getDecodingReader​(java.io.InputStream stream,
                                               java.nio.charset.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, its 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 java.io.Reader getDecodingReader​(java.io.File file,
                                               java.nio.charset.Charset charSet)
                                        throws java.io.IOException
        Opens a Reader for the given File 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, its not recommended to use as a common purpose reader.

        Parameters:
        file - the file to open a reader on
        charSet - the expected charset
        Returns:
        a reader to read the given file
        Throws:
        java.io.IOException

      • getDecodingReader

        public static java.io.Reader getDecodingReader​(java.lang.Class<?> clazz,
                                               java.lang.String resource,
                                               java.nio.charset.Charset charSet)
                                        throws java.io.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, its 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:
        java.io.IOException

      • deleteFilesIgnoringExceptions

        public static void deleteFilesIgnoringExceptions​(Directory dir,
                                                 java.lang.String... files)
        Deletes all given files, suppressing all thrown IOExceptions.

        Note that the files should not be null.

      • copy

        public static void copy​(java.io.File source,
                        java.io.File target)
                 throws java.io.IOException
        Copy one file's contents to another file. The target will be overwritten if it exists. The source must exist.
        Throws:
        java.io.IOException

      • reThrow

        public static void reThrow​(java.lang.Throwable th)
                    throws java.io.IOException
        Simple utilty method that takes a previously caught Throwable and rethrows either IOException or an unchecked exception. If the argument is null then this method does nothing.
        Throws:
        java.io.IOException

      • reThrowUnchecked

        public static void reThrowUnchecked​(java.lang.Throwable th)
        Simple utilty method that takes a previously caught Throwable and rethrows it as an unchecked exception. If the argument is null then this method does nothing.