enhancement-engines/tika/src/main/java/org/apache/stanbol/enhancer/engines/tika/handler/PlainTextHandler.java

/*
* 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.
*/
package org.apache.stanbol.enhancer.engines.tika.handler;

import java.io.Writer;

import org.apache.tika.sax.ToTextContentHandler;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
/**
 * Small extensions to the default {@link ToTextContentHandler}. This allows
 * to <ul>
 * <li>skip ignoreable whitespaces
 * <li>skip linebreaks within literals
 * </ul>
 * 
 * @author Rupert Westenthaler
 *
 */
public class PlainTextHandler extends ToTextContentHandler {

    private static char[] SPACE = new char[]{' '};
    
    
    private final boolean skipWhitespaces;
    private final boolean skipLinebreakes;
    boolean addedText = false;
    public PlainTextHandler(Writer writer, boolean skipIgnoreableWhitespaces, boolean skipLinebreaksWithinLiterals) {
        super(writer);
        this.skipWhitespaces = skipIgnoreableWhitespaces;
        this.skipLinebreakes = skipLinebreaksWithinLiterals;
    }

    @Override
    public void ignorableWhitespace(char[] ch, int start, int length) throws SAXException {
        if(!skipWhitespaces && addedText){
            super.characters(ch, start, length);
            addedText = false;
        } //else ignore
    }
    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        if(skipLinebreakes){
            int end = start+length;
            for(int pos = start; pos<end;pos++){
                if(ch[pos] == '\n'){
                    if(pos > start){
                        super.characters(ch, start, pos-start);
                        super.characters(SPACE, 0, 1);
                    }
                    start = pos+1;
                    length = length-start;
                } //ignore line breaks
            }
        }
        if(length > 0) {
            super.characters(ch, start, length);
        }
        addedText = true;
    }
    
    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
//        if(skipLinebreakes & addedText){
//            characters(LINEBREAK, 0, 1);
//            addedText = false;
//        }
        super.endElement(uri, localName, qName);
    }
}