/* * 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.util; import org.apache.tinkerpop.gremlin.process.traversal.TraversalSideEffects; import java.util.Collections; import java.util.Optional; import java.util.Set; import java.util.function.BinaryOperator; import java.util.function.Supplier; import java.util.function.UnaryOperator; /** * @author Marko A. Rodriguez (http://markorodriguez.com) */ public final class EmptyTraversalSideEffects implements TraversalSideEffects { private static final EmptyTraversalSideEffects INSTANCE = new EmptyTraversalSideEffects(); private EmptyTraversalSideEffects() { } @Override public void set(final String key, final Object value) throws IllegalArgumentException { throw TraversalSideEffects.Exceptions.sideEffectKeyDoesNotExist(key); } @Override public <V> V get(final String key) throws IllegalArgumentException { throw TraversalSideEffects.Exceptions.sideEffectKeyDoesNotExist(key); } @Override public void remove(final String key) throws IllegalArgumentException { throw TraversalSideEffects.Exceptions.sideEffectKeyDoesNotExist(key); } @Override public Set<String> keys() { return Collections.emptySet(); } @Override public void add(final String key, final Object value) throws IllegalArgumentException { throw TraversalSideEffects.Exceptions.sideEffectKeyDoesNotExist(key); } @Override public <V> void register(final String key, final Supplier<V> initialValue, final BinaryOperator<V> reducer) { } @Override public <V> void registerIfAbsent(final String key, final Supplier<V> initialValue, final BinaryOperator<V> reducer) { } @Override public <V> BinaryOperator<V> getReducer(final String key) throws IllegalArgumentException { throw TraversalSideEffects.Exceptions.sideEffectKeyDoesNotExist(key); } @Override public <V> Supplier<V> getSupplier(final String key) throws IllegalArgumentException { throw TraversalSideEffects.Exceptions.sideEffectKeyDoesNotExist(key); } @Override public void registerSupplier(final String key, final Supplier supplier) { } @Override public <V> Optional<Supplier<V>> getRegisteredSupplier(final String key) { return Optional.empty(); } @Override public <S> void setSack(final Supplier<S> initialValue, final UnaryOperator<S> splitOperator, final BinaryOperator<S> mergeOperator) { } @Override public <S> Supplier<S> getSackInitialValue() { return null; } @Override public <S> UnaryOperator<S> getSackSplitter() { return null; } @Override public <S> BinaryOperator<S> getSackMerger() { return null; } @SuppressWarnings("CloneDoesntCallSuperClone") @Override public TraversalSideEffects clone() { return this; } @Override public void mergeInto(final TraversalSideEffects sideEffects) { } public static EmptyTraversalSideEffects instance() { return INSTANCE; } }