Java InputStream Read by Charset processSubstitute(CharBuffer cb, String replacement, boolean endOfInput, String outputCharset, OutputStream os)

Description

Scan the characters in the buffer and do replacement.

License

Apache License

Parameter

Parameter	Description
cb	The char buffer to be scanned
replacement	The replacement string that will be used to replace found occurrences of the keyword
endOfInput	Whether this is the last batch to scan
outputCharset	The charset to encode the output
os	The output stream to receive the output

Exception

Parameter	Description
IOException	an exception

Return

true if the keyword is found, otherwise false

Declaration

public static boolean processSubstitute(CharBuffer cb,
        String replacement, boolean endOfInput, String outputCharset,
        OutputStream os) throws IOException 

Method Source Code

//package com.java2s;
/*//www.jav a 2  s. c o  m
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" 
 * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License.
 */

import java.io.IOException;
import java.io.OutputStream;
import java.nio.CharBuffer;
import java.util.regex.Pattern;

public class Main {
    private final static String KEYWORD = "</body>";
    private final static Pattern SEARCH_PATTERN = Pattern.compile("(?i)"
            + KEYWORD);

    /**
     * Scan the characters in the buffer and do replacement.
     * 
     * The char buffer should be ready for "get" before entering this method,
     * and will change to be ready for "put" after exiting this method.
     * 
     * @param cb
     *            The char buffer to be scanned
     * @param replacement
     *            The replacement string that will be used to replace found
     *            occurrences of the keyword
     * @param endOfInput
     *            Whether this is the last batch to scan
     * @param outputCharset
     *            The charset to encode the output
     * @param os
     *            The output stream to receive the output
     * @return true if the keyword is found, otherwise false
     * @throws IOException
     */
    public static boolean processSubstitute(CharBuffer cb,
            String replacement, boolean endOfInput, String outputCharset,
            OutputStream os) throws IOException {
        int remaining = cb.remaining();
        if (remaining == 0) {
            cb.clear();
            return false;
        }
        String result = SEARCH_PATTERN.matcher(cb)
                .replaceFirst(replacement);
        cb.clear();
        // For simplicity, we assume that the length of the replacement is
        // different from the keyword, which is definitely true in Geronimo
        // admin console's case
        if (result.length() != remaining) {
            // Replacement happened, we've got a match
            os.write(result.getBytes(outputCharset));
            return true;
        } else if (endOfInput) {
            // End of input, write everything out
            os.write(result.getBytes(outputCharset));
            return false;
        } else {
            // Push back the last N chars so that we don't break a keyword
            char tail = result.charAt(result.length() - 1);
            if (tail != ' ' && tail != '\n' && tail != '\r') {
                int textTailLength = Math.min(result.length(),
                        KEYWORD.length() - 1);
                int textTailOffset = result.length() - textTailLength;
                cb.put(result.substring(textTailOffset));
                if (textTailOffset > 0) {
                    os.write(result.substring(0, textTailOffset).getBytes(
                            outputCharset));
                }
            } else {
                os.write(result.getBytes(outputCharset));
            }
            return false;
        }
    }
}

Related

1. inputStreamToString(InputStream inputStream, String charset)
2. inputStreamToString(InputStream is, Charset charset)
3. isCharsetMisInterpreted(String input, String encoding)
4. lines(InputStream in, Charset cs)
5. loadInputStream(InputStream in, Charset cs)
6. stream2Bytes(InputStream is, Charset charset)
7. streamString(InputStream in, boolean closeIn, String charset)
8. streamToString(final InputStream is, final Charset charset)
9. streamToString(InputStream inputStream, Charset encoding)