org.apache.lucene.util

Class IOUtils

java.lang.Object

org.apache.lucene.util.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 and 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

Modifier and Type	Method and 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 void	closeWhileHandlingException(java.io.Closeable... objects) Closes all given Closeables, suppressing all thrown exceptions.
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.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.lang.Class<?> clazz, java.lang.String resource, java.nio.charset.Charset charSet) Opens a Reader for the given resource using a CharsetDecoder.
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 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.