graphpack.matching.ResultSet.java Source code

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Here is the source code for graphpack.matching.ResultSet.java

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/*******************************************************************************
 * Copyright 2012 Amit Portnoy
 * 
 * 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 graphpack.matching;

import java.io.Serializable;
import java.util.Set;

import com.google.common.collect.HashMultiset;
import com.google.common.collect.ImmutableMultiset;
import com.google.common.collect.Multiset;

/**
 * a multi-set of matched results (the same result can be repeated - in the future this behavior may be customized)
 * @author amitport
 */
public class ResultSet implements Serializable {
    private static final long serialVersionUID = -6513155130201864844L;

    final private Multiset<Result> results;

    public ResultSet() {
        results = HashMultiset.create();
    }

    private ResultSet(Multiset<Result> results) {
        this.results = results;
    }

    /**
     * check if there are any results
     * @return true IFF there are no results
     */
    public boolean isEmpty() {
        return results.isEmpty();
    }

    /**
     * adds a single result
     * @param r the result to add
     */
    public void add(Result r) {
        results.add(r);
    }

    /**
     * check if this set contains a specific result
     * @param r the result to look for
     * @return true IFF the result is found
     */
    public boolean contains(Result r) {
        return results.contains(r);
    }

    /**
     * return the a set of distinct results
     * @return distinct results
     */
    public Set<Result> elementSet() {
        return results.elementSet();
    }

    @Override
    public String toString() {
        return results.toString();
    }

    /*** static ***/

    /**
     * Product joins two result sets, entities with the same name are merged
     * if either one is unassigned (if only one of them is assigned we take it's value)
     * or if they point to the same value (otherwise we disregard the result)
     * @return the merged ResultSet
     */
    public static ResultSet product(ResultSet rs1, ResultSet rs2) {
        ResultSet $ = new ResultSet();
        for (Result res1 : rs1.results) {
            for (Result res2 : rs2.results) {
                Result r = Result.merge(res1, res2);
                if (r != null)
                    $.results.add(r);
            }
        }
        return $;
    }

    /**
     * Union of all the results in both input result sets
     * @return the unified result set
     */
    public static ResultSet union(ResultSet rs1, ResultSet rs2) {
        ResultSet $ = new ResultSet();
        $.results.addAll(rs1.results);
        $.results.addAll(rs2.results);
        return $;
    }

    /**
     * create empty result set (&#8709)
     * @return the empty result set
     */
    public static ResultSet Empty() {
        return new ResultSet(new ImmutableMultiset.Builder<Result>().build());
    }

    /**
     * create an epsilon result set ({&#949;}), i.e., a set with single empty result <br/>
     * note that unlike an empty set the epsilon set is considered a successful result
     * @return an epsilon set
     */
    public static ResultSet Epsilon() {
        ResultSet $ = new ResultSet();
        $.add(new Result());
        return $;
    }
}