edu.umd.cs.psl.ui.data.graph.BinaryRelation.java Source code

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Here is the source code for edu.umd.cs.psl.ui.data.graph.BinaryRelation.java

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/*
 * This file is part of the PSL software.
 * Copyright 2011 University of Maryland
 *
 * 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 edu.umd.cs.psl.ui.data.graph;

import org.apache.commons.lang.builder.HashCodeBuilder;

public class BinaryRelation<ET extends EntityType, RT extends RelationType> extends Relation<ET, RT> {

    private final Entity<ET, RT> first;
    private final Entity<ET, RT> second;

    public BinaryRelation(RT type, Entity<ET, RT> _first, Entity<ET, RT> _second) {
        super(type);
        if (type.arity() != 2)
            throw new AssertionError("Expected binary relation type!");
        first = _first;
        second = _second;
    }

    public Entity<ET, RT> getFirst() {
        return first;
    }

    public Entity<ET, RT> getSecond() {
        return second;
    }

    @Override
    public int getArity() {
        return 2;
    }

    @Override
    public Entity<ET, RT> get(int pos) {
        switch (pos) {
        case 0:
            return first;
        case 1:
            return second;
        default:
            throw new ArrayIndexOutOfBoundsException();
        }
    }

    @Override
    public int hashCode() {
        return new HashCodeBuilder().appendSuper(super.hashCode()).append(first.hashCode() + second.hashCode())
                .toHashCode();
    }

    @SuppressWarnings("unchecked")
    @Override
    public boolean equals(Object oth) {
        if (!super.equals(oth))
            return false;
        BinaryRelation<ET, RT> r = (BinaryRelation<ET, RT>) oth;
        return (first.equals(r.first) && second.equals(r.second))
                || (first.equals(r.second) && second.equals(r.first));
    }

}