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A collection of various utility classes to ease working with strings, files, command lines, XML and more.
package org.codehaus.plexus.util;
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.codehaus.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation" and
* "Apache Turbine" must not be used to endorse or promote products
* derived from this software without prior written permission. For
* written permission, please contact [email protected].
*
* 5. Products derived from this software may not be called "Apache",
* "Apache Turbine", nor may "Apache" appear in their name, without
* prior written permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
*
* This class provides static utility methods for input/output operations, particularly buffered copying between sources
* (InputStream, Reader, String and byte[]) and destinations
* (OutputStream, Writer, String and byte[]).
*
*
* Unless otherwise noted, these copy methods do not flush or close the streams. Often, doing so
* would require making non-portable assumptions about the streams' origin and further use. This means that both
* streams' close() methods must be called after copying. if one omits this step, then the stream resources
* (sockets, file descriptors) are released when the associated Stream is garbage-collected. It is not a good idea to
* rely on this mechanism. For a good overview of the distinction between "memory management" and "resource management",
* see this UnixReview article
*
*
* For each copy method, a variant is provided that allows the caller to specify the buffer size (the
* default is 4k). As the buffer size can have a fairly large impact on speed, this may be worth tweaking. Often "large
* buffer -> faster" does not hold, even for large data transfers.
*
*
* For byte-to-char methods, a copy variant allows the encoding to be selected (otherwise the platform
* default is used).
*
*
* The copy methods use an internal buffer when copying. It is therefore advisable not to
* deliberately wrap the stream arguments to the copy methods in Buffered* streams. For
* example, don't do the following:
*
* copy( new BufferedInputStream( in ), new BufferedOutputStream( out ) );
*
* The rationale is as follows:
*
*
* Imagine that an InputStream's read() is a very expensive operation, which would usually suggest wrapping in a
* BufferedInputStream. The BufferedInputStream works by issuing infrequent
* {@link java.io.InputStream#read(byte[] b, int off, int len)} requests on the underlying InputStream, to fill an
* internal buffer, from which further read requests can inexpensively get their data (until the buffer
* runs out).
*
*
* However, the copy methods do the same thing, keeping an internal buffer, populated by
* {@link InputStream#read(byte[] b, int off, int len)} requests. Having two buffers (or three if the destination stream
* is also buffered) is pointless, and the unnecessary buffer management hurts performance slightly (about 3%, according
* to some simple experiments).
*
*
* @author Peter Donald
* @author Jeff Turner
* @version $Id$
* @since 4.0
*/
/*
* Behold, intrepid explorers; a map of this class: Method Input Output Dependency ------ ----- ------ ------- 1 copy
* InputStream OutputStream (primitive) 2 copy Reader Writer (primitive) 3 copy InputStream Writer 2 4 toString
* InputStream String 3 5 toByteArray InputStream byte[] 1 6 copy Reader OutputStream 2 7 toString Reader String 2 8
* toByteArray Reader byte[] 6 9 copy String OutputStream 2 10 copy String Writer (trivial) 11 toByteArray String byte[]
* 9 12 copy byte[] Writer 3 13 toString byte[] String 12 14 copy byte[] OutputStream (trivial) Note that only the first
* two methods shuffle bytes; the rest use these two, or (if possible) copy using native Java copy methods. As there are
* method variants to specify buffer size and encoding, each row may correspond to up to 4 methods.
*/
public final class IOUtil
{
private static final int DEFAULT_BUFFER_SIZE = 1024 * 16;
/**
* Private constructor to prevent instantiation.
*/
private IOUtil()
{
}
///////////////////////////////////////////////////////////////
// Core copy methods
///////////////////////////////////////////////////////////////
/**
* Copy bytes from an InputStream to an OutputStream.
*/
public static void copy( final InputStream input, final OutputStream output )
throws IOException
{
copy( input, output, DEFAULT_BUFFER_SIZE );
}
/**
* Copy bytes from an InputStream to an OutputStream.
*
* @param bufferSize Size of internal buffer to use.
*/
public static void copy( final InputStream input, final OutputStream output, final int bufferSize )
throws IOException
{
final byte[] buffer = new byte[bufferSize];
int n = 0;
while ( 0 <= ( n = input.read( buffer ) ) )
{
output.write( buffer, 0, n );
}
}
/**
* Copy chars from a Reader to a Writer.
*/
public static void copy( final Reader input, final Writer output )
throws IOException
{
copy( input, output, DEFAULT_BUFFER_SIZE );
}
/**
* Copy chars from a Reader to a Writer.
*
* @param bufferSize Size of internal buffer to use.
*/
public static void copy( final Reader input, final Writer output, final int bufferSize )
throws IOException
{
final char[] buffer = new char[bufferSize];
int n = 0;
while ( 0 <= ( n = input.read( buffer ) ) )
{
output.write( buffer, 0, n );
}
output.flush();
}
///////////////////////////////////////////////////////////////
// Derived copy methods
// InputStream -> *
///////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////
// InputStream -> Writer
/**
* Copy and convert bytes from an InputStream to chars on a Writer. The platform's default
* encoding is used for the byte-to-char conversion.
*/
public static void copy( final InputStream input, final Writer output )
throws IOException
{
copy( input, output, DEFAULT_BUFFER_SIZE );
}
/**
* Copy and convert bytes from an InputStream to chars on a Writer. The platform's default
* encoding is used for the byte-to-char conversion.
*
* @param bufferSize Size of internal buffer to use.
*/
public static void copy( final InputStream input, final Writer output, final int bufferSize )
throws IOException
{
final InputStreamReader in = new InputStreamReader( input );
copy( in, output, bufferSize );
}
/**
* Copy and convert bytes from an InputStream to chars on a Writer, using the specified
* encoding.
*
* @param encoding The name of a supported character encoding. See the
* IANA Charset Registry for a list of valid
* encoding types.
*/
public static void copy( final InputStream input, final Writer output, final String encoding )
throws IOException
{
final InputStreamReader in = new InputStreamReader( input, encoding );
copy( in, output );
}
/**
* Copy and convert bytes from an InputStream to chars on a Writer, using the specified
* encoding.
*
* @param encoding The name of a supported character encoding. See the
* IANA Charset Registry for a list of valid
* encoding types.
* @param bufferSize Size of internal buffer to use.
*/
public static void copy( final InputStream input, final Writer output, final String encoding, final int bufferSize )
throws IOException
{
final InputStreamReader in = new InputStreamReader( input, encoding );
copy( in, output, bufferSize );
}
///////////////////////////////////////////////////////////////
// InputStream -> String
/**
* Get the contents of an InputStream as a String. The platform's default encoding is used for the
* byte-to-char conversion.
*/
public static String toString( final InputStream input )
throws IOException
{
return toString( input, DEFAULT_BUFFER_SIZE );
}
/**
* Get the contents of an InputStream as a String. The platform's default encoding is used for the
* byte-to-char conversion.
*
* @param bufferSize Size of internal buffer to use.
*/
public static String toString( final InputStream input, final int bufferSize )
throws IOException
{
final StringWriter sw = new StringWriter();
copy( input, sw, bufferSize );
return sw.toString();
}
/**
* Get the contents of an InputStream as a String.
*
* @param encoding The name of a supported character encoding. See the
* IANA Charset Registry for a list of valid
* encoding types.
*/
public static String toString( final InputStream input, final String encoding )
throws IOException
{
return toString( input, encoding, DEFAULT_BUFFER_SIZE );
}
/**
* Get the contents of an InputStream as a String.
*
* @param encoding The name of a supported character encoding. See the
* IANA Charset Registry for a list of valid
* encoding types.
* @param bufferSize Size of internal buffer to use.
*/
public static String toString( final InputStream input, final String encoding, final int bufferSize )
throws IOException
{
final StringWriter sw = new StringWriter();
copy( input, sw, encoding, bufferSize );
return sw.toString();
}
///////////////////////////////////////////////////////////////
// InputStream -> byte[]
/**
* Get the contents of an InputStream as a byte[].
*/
public static byte[] toByteArray( final InputStream input )
throws IOException
{
return toByteArray( input, DEFAULT_BUFFER_SIZE );
}
/**
* Get the contents of an InputStream as a byte[].
*
* @param bufferSize Size of internal buffer to use.
*/
public static byte[] toByteArray( final InputStream input, final int bufferSize )
throws IOException
{
final ByteArrayOutputStream output = new ByteArrayOutputStream();
copy( input, output, bufferSize );
return output.toByteArray();
}
///////////////////////////////////////////////////////////////
// Derived copy methods
// Reader -> *
///////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////
// Reader -> OutputStream
/**
* Serialize chars from a Reader to bytes on an OutputStream, and flush the
* OutputStream.
*/
public static void copy( final Reader input, final OutputStream output )
throws IOException
{
copy( input, output, DEFAULT_BUFFER_SIZE );
}
/**
* Serialize chars from a Reader to bytes on an OutputStream, and flush the
* OutputStream.
*
* @param bufferSize Size of internal buffer to use.
*/
public static void copy( final Reader input, final OutputStream output, final int bufferSize )
throws IOException
{
final OutputStreamWriter out = new OutputStreamWriter( output );
copy( input, out, bufferSize );
// NOTE: Unless anyone is planning on rewriting OutputStreamWriter, we have to flush
// here.
out.flush();
}
///////////////////////////////////////////////////////////////
// Reader -> String
/**
* Get the contents of a Reader as a String.
*/
public static String toString( final Reader input )
throws IOException
{
return toString( input, DEFAULT_BUFFER_SIZE );
}
/**
* Get the contents of a Reader as a String.
*
* @param bufferSize Size of internal buffer to use.
*/
public static String toString( final Reader input, final int bufferSize )
throws IOException
{
final StringWriter sw = new StringWriter();
copy( input, sw, bufferSize );
return sw.toString();
}
///////////////////////////////////////////////////////////////
// Reader -> byte[]
/**
* Get the contents of a Reader as a byte[].
*/
public static byte[] toByteArray( final Reader input )
throws IOException
{
return toByteArray( input, DEFAULT_BUFFER_SIZE );
}
/**
* Get the contents of a Reader as a byte[].
*
* @param bufferSize Size of internal buffer to use.
*/
public static byte[] toByteArray( final Reader input, final int bufferSize )
throws IOException
{
ByteArrayOutputStream output = new ByteArrayOutputStream();
copy( input, output, bufferSize );
return output.toByteArray();
}
///////////////////////////////////////////////////////////////
// Derived copy methods
// String -> *
///////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////
// String -> OutputStream
/**
* Serialize chars from a String to bytes on an OutputStream, and flush the
* OutputStream.
*/
public static void copy( final String input, final OutputStream output )
throws IOException
{
copy( input, output, DEFAULT_BUFFER_SIZE );
}
/**
* Serialize chars from a String to bytes on an OutputStream, and flush the
* OutputStream.
*
* @param bufferSize Size of internal buffer to use.
*/
public static void copy( final String input, final OutputStream output, final int bufferSize )
throws IOException
{
final StringReader in = new StringReader( input );
final OutputStreamWriter out = new OutputStreamWriter( output );
copy( in, out, bufferSize );
// NOTE: Unless anyone is planning on rewriting OutputStreamWriter, we have to flush
// here.
out.flush();
}
///////////////////////////////////////////////////////////////
// String -> Writer
/**
* Copy chars from a String to a Writer.
*/
public static void copy( final String input, final Writer output )
throws IOException
{
output.write( input );
}
/**
* Copy bytes from an InputStream to an OutputStream, with buffering. This is equivalent
* to passing a {@link java.io.BufferedInputStream} and {@link java.io.BufferedOutputStream} to
* {@link #copy(InputStream, OutputStream)}, and flushing the output stream afterwards. The streams are not closed
* after the copy.
*
* @deprecated Buffering streams is actively harmful! See the class description as to why. Use
* {@link #copy(InputStream, OutputStream)} instead.
*/
public static void bufferedCopy( final InputStream input, final OutputStream output )
throws IOException
{
final BufferedInputStream in = new BufferedInputStream( input );
final BufferedOutputStream out = new BufferedOutputStream( output );
copy( in, out );
out.flush();
}
///////////////////////////////////////////////////////////////
// String -> byte[]
/**
* Get the contents of a String as a byte[].
*/
public static byte[] toByteArray( final String input )
throws IOException
{
return toByteArray( input, DEFAULT_BUFFER_SIZE );
}
/**
* Get the contents of a String as a byte[].
*
* @param bufferSize Size of internal buffer to use.
*/
public static byte[] toByteArray( final String input, final int bufferSize )
throws IOException
{
ByteArrayOutputStream output = new ByteArrayOutputStream();
copy( input, output, bufferSize );
return output.toByteArray();
}
///////////////////////////////////////////////////////////////
// Derived copy methods
// byte[] -> *
///////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////
// byte[] -> Writer
/**
* Copy and convert bytes from a byte[] to chars on a Writer. The platform's default
* encoding is used for the byte-to-char conversion.
*/
public static void copy( final byte[] input, final Writer output )
throws IOException
{
copy( input, output, DEFAULT_BUFFER_SIZE );
}
/**
* Copy and convert bytes from a byte[] to chars on a Writer. The platform's default
* encoding is used for the byte-to-char conversion.
*
* @param bufferSize Size of internal buffer to use.
*/
public static void copy( final byte[] input, final Writer output, final int bufferSize )
throws IOException
{
final ByteArrayInputStream in = new ByteArrayInputStream( input );
copy( in, output, bufferSize );
}
/**
* Copy and convert bytes from a byte[] to chars on a Writer, using the specified
* encoding.
*
* @param encoding The name of a supported character encoding. See the
* IANA Charset Registry for a list of valid
* encoding types.
*/
public static void copy( final byte[] input, final Writer output, final String encoding )
throws IOException
{
final ByteArrayInputStream in = new ByteArrayInputStream( input );
copy( in, output, encoding );
}
/**
* Copy and convert bytes from a byte[] to chars on a Writer, using the specified
* encoding.
*
* @param encoding The name of a supported character encoding. See the
* IANA Charset Registry for a list of valid
* encoding types.
* @param bufferSize Size of internal buffer to use.
*/
public static void copy( final byte[] input, final Writer output, final String encoding, final int bufferSize )
throws IOException
{
final ByteArrayInputStream in = new ByteArrayInputStream( input );
copy( in, output, encoding, bufferSize );
}
///////////////////////////////////////////////////////////////
// byte[] -> String
/**
* Get the contents of a byte[] as a String. The platform's default encoding is used for the
* byte-to-char conversion.
*/
public static String toString( final byte[] input )
throws IOException
{
return toString( input, DEFAULT_BUFFER_SIZE );
}
/**
* Get the contents of a byte[] as a String. The platform's default encoding is used for the
* byte-to-char conversion.
*
* @param bufferSize Size of internal buffer to use.
*/
public static String toString( final byte[] input, final int bufferSize )
throws IOException
{
final StringWriter sw = new StringWriter();
copy( input, sw, bufferSize );
return sw.toString();
}
/**
* Get the contents of a byte[] as a String.
*
* @param encoding The name of a supported character encoding. See the
* IANA Charset Registry for a list of valid
* encoding types.
*/
public static String toString( final byte[] input, final String encoding )
throws IOException
{
return toString( input, encoding, DEFAULT_BUFFER_SIZE );
}
/**
* Get the contents of a byte[] as a String.
*
* @param encoding The name of a supported character encoding. See the
* IANA Charset Registry for a list of valid
* encoding types.
* @param bufferSize Size of internal buffer to use.
*/
public static String toString( final byte[] input, final String encoding, final int bufferSize )
throws IOException
{
final StringWriter sw = new StringWriter();
copy( input, sw, encoding, bufferSize );
return sw.toString();
}
///////////////////////////////////////////////////////////////
// byte[] -> OutputStream
/**
* Copy bytes from a byte[] to an OutputStream.
*/
public static void copy( final byte[] input, final OutputStream output )
throws IOException
{
copy( input, output, DEFAULT_BUFFER_SIZE );
}
/**
* Copy bytes from a byte[] to an OutputStream.
*
* @param bufferSize Size of internal buffer to use.
*/
public static void copy( final byte[] input, final OutputStream output, final int bufferSize )
throws IOException
{
output.write( input );
}
/**
* Compare the contents of two Streams to determine if they are equal or not.
*
* @param input1 the first stream
* @param input2 the second stream
* @return true if the content of the streams are equal or they both don't exist, false otherwise
*/
public static boolean contentEquals( final InputStream input1, final InputStream input2 )
throws IOException
{
final InputStream bufferedInput1 = new BufferedInputStream( input1 );
final InputStream bufferedInput2 = new BufferedInputStream( input2 );
int ch = bufferedInput1.read();
while ( 0 <= ch )
{
final int ch2 = bufferedInput2.read();
if ( ch != ch2 )
{
return false;
}
ch = bufferedInput1.read();
}
final int ch2 = bufferedInput2.read();
if ( 0 <= ch2 )
{
return false;
}
else
{
return true;
}
}
// ----------------------------------------------------------------------
// closeXXX()
// ----------------------------------------------------------------------
/**
* Closes the input stream. The input stream can be null and any IOException's will be swallowed.
*
* @param inputStream The stream to close.
*/
public static void close( InputStream inputStream )
{
if ( inputStream == null )
{
return;
}
try
{
inputStream.close();
}
catch ( IOException ex )
{
// ignore
}
}
/**
* Closes a channel. Channel can be null and any IOException's will be swallowed.
*
* @param channel The stream to close.
*/
public static void close( Channel channel )
{
if ( channel == null )
{
return;
}
try
{
channel.close();
}
catch ( IOException ex )
{
// ignore
}
}
/**
* Closes the output stream. The output stream can be null and any IOException's will be swallowed.
*
* @param outputStream The stream to close.
*/
public static void close( OutputStream outputStream )
{
if ( outputStream == null )
{
return;
}
try
{
outputStream.close();
}
catch ( IOException ex )
{
// ignore
}
}
/**
* Closes the reader. The reader can be null and any IOException's will be swallowed.
*
* @param reader The reader to close.
*/
public static void close( Reader reader )
{
if ( reader == null )
{
return;
}
try
{
reader.close();
}
catch ( IOException ex )
{
// ignore
}
}
/**
* Closes the writer. The writer can be null and any IOException's will be swallowed.
*
* @param writer The writer to close.
*/
public static void close( Writer writer )
{
if ( writer == null )
{
return;
}
try
{
writer.close();
}
catch ( IOException ex )
{
// ignore
}
}
}