TrailingHeadlineToBoilerplateFilter.java

/**
 * Copyright (C) 2013 Christian Kohlschütter (ckkohl79@gmail.com)
 *
 * Licensed 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 de.l3s.boilerpipe.filters.heuristics;

import java.util.List;
import java.util.ListIterator;

import de.l3s.boilerpipe.BoilerpipeFilter;
import de.l3s.boilerpipe.BoilerpipeProcessingException;
import de.l3s.boilerpipe.document.TextBlock;
import de.l3s.boilerpipe.document.TextDocument;
import de.l3s.boilerpipe.labels.DefaultLabels;

/**
 * Marks trailing headlines ({@link TextBlock}s that have the label {@link de.l3s.boilerpipe.labels.DefaultLabels#HEADING})
 * as boilerplate. Trailing means they are marked content and are below any other content block.
 * 
 * @author Christian Kohlschütter
 */
public final class TrailingHeadlineToBoilerplateFilter implements BoilerpipeFilter {
    public static final TrailingHeadlineToBoilerplateFilter INSTANCE = new TrailingHeadlineToBoilerplateFilter();

    /**
     * Returns the singleton instance for ExpandTitleToContentFilter.
     */
    public static TrailingHeadlineToBoilerplateFilter getInstance() {
        return INSTANCE;
    }

    public boolean process(TextDocument doc)
            throws BoilerpipeProcessingException {
    	boolean changes = false;
    	
    	List<TextBlock> list = doc.getTextBlocks();

    	for (ListIterator<TextBlock> it = list.listIterator(list.size()); it.hasPrevious(); ) {
    		TextBlock tb = it.previous();
    		if(tb.isContent()) {
    			if(tb.hasLabel(DefaultLabels.HEADING)) {
    				tb.setIsContent(false);
    				changes = true;
    			} else {
    				break;
    			}
    		}
    	}
    	
        return changes;
    }

}