ListAtEndFilter.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 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 nested list-item blocks after the end of the main content.
 * 
 * @author Christian Kohlschütter
 */
public final class ListAtEndFilter implements BoilerpipeFilter {
	public static final ListAtEndFilter INSTANCE = new ListAtEndFilter();

	private ListAtEndFilter() {
	}

	public boolean process(final TextDocument doc)
			throws BoilerpipeProcessingException {

		boolean changes = false;

		int tagLevel = Integer.MAX_VALUE;
		for (TextBlock tb : doc.getTextBlocks()) {
			if (tb.isContent()
					&& tb.hasLabel(DefaultLabels.VERY_LIKELY_CONTENT)) {
				tagLevel = tb.getTagLevel();
			} else {
				if (tb.getTagLevel() > tagLevel
						&& tb.hasLabel(DefaultLabels.MIGHT_BE_CONTENT)
						&& tb.hasLabel(DefaultLabels.LI)
						&& tb.getLinkDensity() == 0
						) {
					tb.setIsContent(true);
					changes = true;
				} else {
					tagLevel = Integer.MAX_VALUE;
				}
			}
		}

		return changes;

	}
}