/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.tinkerpop.gremlin.process.computer.traversal.lambda;

import org.apache.tinkerpop.gremlin.process.computer.traversal.TraversalVertexProgram;
import org.apache.tinkerpop.gremlin.process.traversal.Traverser;
import org.apache.tinkerpop.gremlin.process.traversal.lambda.AbstractLambdaTraversal;
import org.apache.tinkerpop.gremlin.process.traversal.traverser.util.TraverserSet;
import org.apache.tinkerpop.gremlin.structure.Vertex;
import org.apache.tinkerpop.gremlin.structure.VertexProperty;

/**
 * @author Marko A. Rodriguez (http://markorodriguez.com)
 */
public final class HaltedTraversersCountTraversal extends AbstractLambdaTraversal<Vertex, Long> {

    private Long count;

    @Override
    public Long next() {
        return this.count;
    }

    @Override
    public void addStart(final Traverser.Admin<Vertex> start) {
        final VertexProperty<TraverserSet<Object>> property = start.get().<TraverserSet<Object>>property(TraversalVertexProgram.HALTED_TRAVERSERS);
        this.count = property.isPresent() ? property.value().bulkSize() : 0l;
    }

    @Override
    public String toString() {
        return "count(" + TraversalVertexProgram.HALTED_TRAVERSERS + ")";
    }

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