| /* |
| * 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.traverser.util; |
| |
| import org.apache.tinkerpop.gremlin.process.traversal.Path; |
| import org.apache.tinkerpop.gremlin.process.traversal.Step; |
| import org.apache.tinkerpop.gremlin.process.traversal.TraversalSideEffects; |
| import org.apache.tinkerpop.gremlin.process.traversal.Traverser; |
| import org.apache.tinkerpop.gremlin.process.traversal.step.util.EmptyPath; |
| import org.apache.tinkerpop.gremlin.structure.util.Attachable; |
| |
| import java.util.Collections; |
| import java.util.Set; |
| import java.util.function.Function; |
| |
| /** |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| */ |
| public final class EmptyTraverser<T> implements Traverser<T>, Traverser.Admin<T> { |
| |
| private static final EmptyTraverser INSTANCE = new EmptyTraverser(); |
| |
| public static <R> EmptyTraverser<R> instance() { |
| return INSTANCE; |
| } |
| |
| private EmptyTraverser() { |
| |
| } |
| |
| @Override |
| public void addLabels(final Set<String> labels) { |
| |
| } |
| |
| @Override |
| public void set(final T t) { |
| |
| } |
| |
| @Override |
| public void incrLoops(final String stepLabel) { |
| |
| } |
| |
| @Override |
| public void resetLoops() { |
| |
| } |
| |
| @Override |
| public String getStepId() { |
| return HALT; |
| } |
| |
| @Override |
| public void setStepId(final String stepId) { |
| |
| } |
| |
| @Override |
| public void setBulk(long count) { |
| |
| } |
| |
| @Override |
| public <R> Admin<R> split(final R r, final Step<T, R> step) { |
| return INSTANCE; |
| } |
| |
| @Override |
| public Admin<T> split() { |
| return this; |
| } |
| |
| @Override |
| public Admin<T> detach() { |
| return this; |
| } |
| |
| @Override |
| public T attach(final Function<Attachable<T>, T> method) { |
| return null; |
| } |
| |
| @Override |
| public void setSideEffects(final TraversalSideEffects sideEffects) { |
| |
| } |
| |
| @Override |
| public T get() { |
| return null; |
| } |
| |
| @Override |
| public <S> S sack() { |
| return null; |
| } |
| |
| @Override |
| public <S> void sack(final S object) { |
| |
| } |
| |
| @Override |
| public void merge(final Traverser.Admin<?> other) { |
| |
| } |
| |
| @Override |
| public Path path() { |
| return EmptyPath.instance(); |
| } |
| |
| @Override |
| public int loops() { |
| return 0; |
| } |
| |
| @Override |
| public long bulk() { |
| return 0l; |
| } |
| |
| @Override |
| public TraversalSideEffects getSideEffects() { |
| return null; |
| } |
| |
| @Override |
| public Set<String> getTags() { |
| return Collections.emptySet(); |
| } |
| |
| @Override |
| public int hashCode() { |
| return 380473707; |
| } |
| |
| @Override |
| public boolean equals(final Object object) { |
| return object instanceof EmptyTraverser; |
| } |
| |
| @Override |
| @SuppressWarnings("CloneDoesntCallSuperClone") |
| public EmptyTraverser<T> clone() { |
| return this; |
| } |
| } |