| /* |
| * 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 static com.google.common.base.Preconditions.checkNotNull; |
| |
| import com.google.common.collect.AbstractIterator; |
| import com.google.common.collect.UnmodifiableIterator; |
| import java.util.AbstractSet; |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.Map.Entry; |
| import org.checkerframework.checker.nullness.qual.Nullable; |
| |
| /** |
| * A class to represent the set of edges connecting an (implicit) origin node to a target node. |
| * |
| * <p>The {@link #outEdgeToNode} map allows this class to work on networks with parallel edges. See |
| * {@link EdgesConnecting} for a class that is more efficient but forbids parallel edges. |
| * |
| * @author James Sexton |
| * @param <E> Edge parameter type |
| */ |
| abstract class MultiEdgesConnecting<E> extends AbstractSet<E> { |
| |
| private final Map<E, ?> outEdgeToNode; |
| private final Object targetNode; |
| |
| MultiEdgesConnecting(Map<E, ?> outEdgeToNode, Object targetNode) { |
| this.outEdgeToNode = checkNotNull(outEdgeToNode); |
| this.targetNode = checkNotNull(targetNode); |
| } |
| |
| @Override |
| public UnmodifiableIterator<E> iterator() { |
| final Iterator<? extends Entry<E, ?>> entries = outEdgeToNode.entrySet().iterator(); |
| return new AbstractIterator<E>() { |
| @Override |
| protected E computeNext() { |
| while (entries.hasNext()) { |
| Entry<E, ?> entry = entries.next(); |
| if (targetNode.equals(entry.getValue())) { |
| return entry.getKey(); |
| } |
| } |
| return endOfData(); |
| } |
| }; |
| } |
| |
| @Override |
| public boolean contains(@Nullable Object edge) { |
| return targetNode.equals(outEdgeToNode.get(edge)); |
| } |
| } |