Java tutorial
/* * 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.traversal.strategy.finalization; import org.apache.commons.configuration.Configuration; import org.apache.commons.configuration.MapConfiguration; import org.apache.tinkerpop.gremlin.process.traversal.Step; import org.apache.tinkerpop.gremlin.process.traversal.Traversal; import org.apache.tinkerpop.gremlin.process.traversal.TraversalStrategy; import org.apache.tinkerpop.gremlin.process.traversal.step.map.MatchStep; import org.apache.tinkerpop.gremlin.process.traversal.strategy.AbstractTraversalStrategy; import org.apache.tinkerpop.gremlin.structure.util.StringFactory; import java.util.Collections; /** * @author Marko A. Rodriguez (http://markorodriguez.com) */ public final class MatchAlgorithmStrategy extends AbstractTraversalStrategy<TraversalStrategy.FinalizationStrategy> implements TraversalStrategy.FinalizationStrategy { private static final String MATCH_ALGORITHM = "matchAlgorithm"; private Class<? extends MatchStep.MatchAlgorithm> matchAlgorithmClass; private MatchAlgorithmStrategy() { // for serialization } private MatchAlgorithmStrategy(final Class<? extends MatchStep.MatchAlgorithm> matchAlgorithmClass) { this.matchAlgorithmClass = matchAlgorithmClass; } @Override public void apply(final Traversal.Admin<?, ?> traversal) { for (final Step<?, ?> step : traversal.getSteps()) { if (step instanceof MatchStep) { ((MatchStep) step).setMatchAlgorithm(this.matchAlgorithmClass); } } } public static MatchAlgorithmStrategy create(final Configuration configuration) { try { return new MatchAlgorithmStrategy((Class) Class.forName(configuration.getString(MATCH_ALGORITHM))); } catch (final ClassNotFoundException e) { throw new IllegalArgumentException(e.getMessage(), e); } } @Override public Configuration getConfiguration() { return new MapConfiguration(Collections.singletonMap(MATCH_ALGORITHM, null != this.matchAlgorithmClass.getDeclaringClass() ? this.matchAlgorithmClass.getCanonicalName().replace( "." + this.matchAlgorithmClass.getSimpleName(), "$" + this.matchAlgorithmClass.getSimpleName()) : this.matchAlgorithmClass.getCanonicalName())); } public static Builder build() { return new Builder(); } @Override public String toString() { return StringFactory.traversalStrategyString(this); } public final static class Builder { private Class<? extends MatchStep.MatchAlgorithm> matchAlgorithmClass = MatchStep.CountMatchAlgorithm.class; private Builder() { } public Builder algorithm(final Class<? extends MatchStep.MatchAlgorithm> matchAlgorithmClass) { this.matchAlgorithmClass = matchAlgorithmClass; return this; } public MatchAlgorithmStrategy create() { return new MatchAlgorithmStrategy(this.matchAlgorithmClass); } } }