FilterDefinition.java

/**
 * Copyright (C) 2009 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.exoplatform.web.filter;

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;


/**
 * This class defined all the variables needed to define a {@link Filter}
 *
 * Created by The eXo Platform SAS Author : Nicolas Filotto nicolas.filotto@exoplatform.com 25 sept. 2009
 */
public class FilterDefinition {

    /**
     * The filter.
     */
    private Filter filter;

    /**
     * The filter mapping.
     */
    private volatile FilterMapping mapping;

    /**
     * The list of patterns that will defined the {@link FilterMapping}
     */
    private List<String> patterns;

    public FilterDefinition() {
    }

    public FilterDefinition(Filter filter, List<String> patterns) {
        this.filter = filter;
        this.patterns = patterns;
    }

    public Filter getFilter() {
        return filter;
    }

    public FilterMapping getMapping() {
        if (mapping == null) {
            synchronized (this) {
                if (mapping == null) {
                    this.mapping = new PatternMapping(patterns);
                    this.patterns = null;
                }
            }
        }
        return mapping;
    }

    /**
     * This class is used to defined a mapping based on a list of regular expression
     */
    private static class PatternMapping implements FilterMapping {

        /**
         * the list of regular expressions
         */
        private final List<Pattern> patterns;

        private PatternMapping(List<String> strPatterns) {
            if (strPatterns == null || strPatterns.isEmpty()) {
                throw new IllegalArgumentException("The list of patterns cannot be empty");
            }
            this.patterns = new ArrayList<Pattern>(strPatterns.size());
            for (String sPattern : strPatterns) {
                patterns.add(Pattern.compile(sPattern));
            }
        }

        /**
         * @return <code>true</code> if at least one pattern matches
         */
        public boolean match(String path) {
            for (int i = 0, length = patterns.size(); i < length; i++) {
                Pattern pattern = patterns.get(i);
                Matcher matcher = pattern.matcher(path);
                if (matcher.matches()) {
                    return true;
                }
            }
            return false;
        }

    }
}