| /* |
| * 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.clerezza.commons.rdf.impl.utils; |
| |
| import java.util.Collection; |
| import java.util.Iterator; |
| |
| import org.apache.clerezza.commons.rdf.BlankNode; |
| import org.apache.clerezza.commons.rdf.ImmutableGraph; |
| import org.apache.clerezza.commons.rdf.RDFTerm; |
| import org.apache.clerezza.commons.rdf.Triple; |
| import org.apache.clerezza.commons.rdf.impl.utils.graphmatching.GraphMatcher; |
| |
| /** |
| * <code>AbstractGraph</code> is an abstract implementation of <code>ImmutableGraph</code> |
| * implementing the <code>equals</code> and the <code>hashCode</code> methods. |
| * |
| * @author reto |
| * |
| */ |
| public abstract class AbstractImmutableGraph extends AbstractGraph |
| implements ImmutableGraph { |
| |
| public final synchronized int hashCode() { |
| int result = 0; |
| for (Iterator<Triple> iter = iterator(); iter.hasNext();) { |
| result += getBlankNodeBlindHash(iter.next()); |
| } |
| return result; |
| } |
| |
| /** |
| * @param triple |
| * @return hash without BNode hashes |
| */ |
| private int getBlankNodeBlindHash(Triple triple) { |
| int hash = triple.getPredicate().hashCode(); |
| RDFTerm subject = triple.getSubject(); |
| |
| if (!(subject instanceof BlankNode)) { |
| hash ^= subject.hashCode() >> 1; |
| } |
| RDFTerm object = triple.getObject(); |
| if (!(object instanceof BlankNode)) { |
| hash ^= object.hashCode() << 1; |
| } |
| |
| return hash; |
| } |
| |
| @Override |
| public boolean add(Triple e) { |
| throw new UnsupportedOperationException("Graphs are not mutable, use Graph"); |
| |
| } |
| |
| @Override |
| public boolean addAll(Collection<? extends Triple> c) { |
| throw new UnsupportedOperationException("Graphs are not mutable, use Graph"); |
| } |
| |
| @Override |
| public boolean remove(Object o) { |
| throw new UnsupportedOperationException("Graphs are not mutable, use Graph"); |
| } |
| |
| @Override |
| public boolean removeAll(Collection<?> c) { |
| throw new UnsupportedOperationException("Graphs are not mutable, use Graph"); |
| } |
| |
| @Override |
| public void clear() { |
| throw new UnsupportedOperationException("Graphs are not mutable, use Graph"); |
| } |
| |
| |
| @Override |
| public ImmutableGraph getImmutableGraph() { |
| return this; |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) { |
| return true; |
| } |
| if (!(obj instanceof ImmutableGraph)) { |
| return false; |
| } |
| if (hashCode() != obj.hashCode()) { |
| return false; |
| } |
| return GraphMatcher.getValidMapping(this, (ImmutableGraph) obj) != null; |
| } |
| } |