/*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2002-2003 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 acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.codehaus.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "Ant" and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact codehaus@codehaus.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
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*
* 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
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* 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
* .
*/
package org.codehaus.plexus.util;
import java.io.FilterReader;
import java.io.IOException;
import java.io.Reader;
import java.util.HashMap;
import java.util.Map;
/**
*/
public class InterpolationFilterReader
extends FilterReader
{
/** replacement text from a token */
private String replaceData = null;
/** Index into replacement data */
private int replaceIndex = -1;
/** Index into previous data */
private int previousIndex = -1;
/** Hashtable to hold the replacee-replacer pairs (String to String). */
private Map variables = new HashMap();
/** Character marking the beginning of a token. */
private String beginToken;
/** Character marking the end of a token. */
private String endToken;
/** Length of begin token. */
private int beginTokenLength;
/** Length of end token. */
private int endTokenLength;
/** Default begin token. */
private static String DEFAULT_BEGIN_TOKEN = "${";
/** Default end token. */
private static String DEFAULT_END_TOKEN = "}";
public InterpolationFilterReader( Reader in, Map variables, String beginToken, String endToken )
{
super( in );
this.variables = variables;
this.beginToken = beginToken;
this.endToken = endToken;
beginTokenLength = beginToken.length();
endTokenLength = endToken.length();
}
public InterpolationFilterReader( Reader in, Map variables )
{
this( in, variables, DEFAULT_BEGIN_TOKEN, DEFAULT_END_TOKEN );
}
/**
* Skips characters. This method will block until some characters are
* available, an I/O error occurs, or the end of the stream is reached.
*
* @param n The number of characters to skip
*
* @return the number of characters actually skipped
*
* @exception IllegalArgumentException If n is negative.
* @exception IOException If an I/O error occurs
*/
public long skip( long n ) throws IOException
{
if ( n < 0L )
{
throw new IllegalArgumentException( "skip value is negative" );
}
for ( long i = 0; i < n; i++ )
{
if ( read() == -1 )
{
return i;
}
}
return n;
}
/**
* Reads characters into a portion of an array. This method will block
* until some input is available, an I/O error occurs, or the end of the
* stream is reached.
*
* @param cbuf Destination buffer to write characters to.
* Must not be null.
* @param off Offset at which to start storing characters.
* @param len Maximum number of characters to read.
*
* @return the number of characters read, or -1 if the end of the
* stream has been reached
*
* @exception IOException If an I/O error occurs
*/
public int read( char cbuf[],
int off,
int len )
throws IOException
{
for ( int i = 0; i < len; i++ )
{
int ch = read();
if ( ch == -1 )
{
if ( i == 0 )
{
return -1;
}
else
{
return i;
}
}
cbuf[off + i] = (char) ch;
}
return len;
}
/**
* Returns the next character in the filtered stream, replacing tokens
* from the original stream.
*
* @return the next character in the resulting stream, or -1
* if the end of the resulting stream has been reached
*
* @exception IOException if the underlying stream throws an IOException
* during reading
*/
public int read() throws IOException
{
if ( replaceIndex != -1 && replaceIndex < replaceData.length() )
{
int ch = replaceData.charAt( replaceIndex++ );
if ( replaceIndex >= replaceData.length() )
{
replaceIndex = -1;
}
return ch;
}
int ch = -1;
if ( previousIndex != -1 && previousIndex < endTokenLength )
{
ch = endToken.charAt( previousIndex++ );
}
else
{
ch = in.read();
}
if ( ch == beginToken.charAt( 0 ) )
{
StringBuffer key = new StringBuffer();
int beginTokenMatchPos = 1;
do
{
if ( previousIndex != -1 && previousIndex < endTokenLength )
{
ch = endToken.charAt( previousIndex++ );
}
else
{
ch = in.read();
}
if ( ch != -1 )
{
key.append( (char) ch );
if ( ( beginTokenMatchPos < beginTokenLength ) &&
( ch != beginToken.charAt( beginTokenMatchPos++ ) ) )
{
ch = -1; // not really EOF but to trigger code below
break;
}
}
else
{
break;
}
}
while ( ch != endToken.charAt( 0 ) );
// now test endToken
if ( ch != -1 && endTokenLength > 1 )
{
int endTokenMatchPos = 1;
do
{
if ( previousIndex != -1 && previousIndex < endTokenLength )
{
ch = endToken.charAt( previousIndex++ );
}
else
{
ch = in.read();
}
if ( ch != -1 )
{
key.append( (char) ch );
if ( ch != endToken.charAt( endTokenMatchPos++ ) )
{
ch = -1; // not really EOF but to trigger code below
break;
}
}
else
{
break;
}
}
while ( endTokenMatchPos < endTokenLength );
}
// There is nothing left to read so we have the situation where the begin/end token
// are in fact the same and as there is nothing left to read we have got ourselves
// end of a token boundary so let it pass through.
if ( ch == -1 )
{
replaceData = key.toString();
replaceIndex = 0;
return beginToken.charAt( 0 );
}
String variableKey = key.substring( beginTokenLength - 1, key.length() - endTokenLength );
Object o = variables.get(variableKey);
if ( o != null )
{
String value = o.toString();
if ( value.length() != 0 )
{
replaceData = value;
replaceIndex = 0;
}
return read();
}
else
{
previousIndex = 0;
replaceData = key.substring(0, key.length() - endTokenLength );
replaceIndex = 0;
return beginToken.charAt(0);
}
}
return ch;
}
}