com.google.common.graph.AbstractGraph.java Source code

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Here is the source code for com.google.common.graph.AbstractGraph.java

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/*
 * Copyright (C) 2016 The Guava Authors
 *
 * 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 com.google.common.graph;

import javax.annotation.Nullable;

/**
 * This class provides a skeletal implementation of {@link Graph}. It is recommended to extend this
 * class rather than implement {@link Graph} directly, to ensure consistent {@link #equals(Object)}
 * and {@link #hashCode()} results across different graph implementations.
 *
 * @author James Sexton
 * @param <N> Node parameter type
 */
public abstract class AbstractGraph<N> implements Graph<N> {

    @Override
    public int degree(Object node) {
        // only works for non-multigraphs; multigraphs not yet supported
        return adjacentNodes(node).size();
    }

    @Override
    public int inDegree(Object node) {
        // only works for non-multigraphs; multigraphs not yet supported
        return predecessors(node).size();
    }

    @Override
    public int outDegree(Object node) {
        // only works for non-multigraphs; multigraphs not yet supported
        return successors(node).size();
    }

    @Override
    public boolean equals(@Nullable Object object) {
        if (!(object instanceof Graph)) {
            return false;
        }
        return Graphs.equal(this, (Graph<?>) object);
    }

    @Override
    public int hashCode() {
        return Graphs.hashCode(this);
    }

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