RegularExpressionFilter.java

/**   
 * License Agreement for OpenSearchServer
 *
 * Copyright (C) 2012-2014 Emmanuel Keller / Jaeksoft
 * 
 * http://www.open-search-server.com
 * 
 * This file is part of OpenSearchServer.
 *
 * OpenSearchServer is free software: you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 * OpenSearchServer is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with OpenSearchServer. 
 *  If not, see <http://www.gnu.org/licenses/>.
 **/

package com.jaeksoft.searchlib.analysis.filter;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Pattern;

import org.apache.lucene.analysis.TokenStream;

import com.jaeksoft.searchlib.SearchLibException;
import com.jaeksoft.searchlib.analysis.ClassPropertyEnum;
import com.jaeksoft.searchlib.analysis.FilterFactory;
import com.jaeksoft.searchlib.util.RegExpUtils;

public class RegularExpressionFilter extends FilterFactory {

	private Pattern pattern = null;

	@Override
	protected void initProperties() throws SearchLibException {
		super.initProperties();
		addProperty(ClassPropertyEnum.REGULAR_EXPRESSION, "", null, 20, 1);
	}

	@Override
	public void checkValue(ClassPropertyEnum prop, String value)
			throws SearchLibException {
		if (prop != ClassPropertyEnum.REGULAR_EXPRESSION)
			return;
		if (value == null || value.length() == 0)
			return;
		pattern = Pattern.compile(value);
	}

	@Override
	public TokenStream create(TokenStream tokenStream) {
		if (pattern == null)
			return tokenStream;
		return new RegularExpressionTokenFilter(pattern, tokenStream);
	}

	public static class RegularExpressionTokenFilter extends AbstractTermFilter
			implements RegExpUtils.MatchGroupListener {

		private List<String> termQueue = null;

		private int currentPos = 0;

		private final Pattern pattern;

		protected RegularExpressionTokenFilter(Pattern pattern,
				TokenStream input) {
			super(input);
			termQueue = new ArrayList<String>(0);
			this.pattern = pattern;
		}

		private final boolean popToken() {
			if (termQueue.size() == 0)
				return false;
			if (currentPos == termQueue.size())
				return false;
			createToken(termQueue.get(currentPos++));
			return true;
		}

		private final void createTokens() {
			termQueue.clear();
			currentPos = 0;

			synchronized (pattern) {
				RegExpUtils.groupExtractor(pattern, termAtt.toString(), this);
			}
		}

		@Override
		public final boolean incrementToken() throws IOException {
			for (;;) {
				if (popToken())
					return true;
				if (!input.incrementToken())
					return false;
				createTokens();
			}
		}

		@Override
		public void match(int start, int end) {
		}

		@Override
		public void group(int start, int end, String content) {
			if (start == end)
				return;
			termQueue.add(content);
		}
	}
}