org.apache.clerezza.ImmutableGraph Maven / Gradle / Ivy
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/*
* 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;
/**
* A graph, modeled as a set of triples.
* This interface does not extend java.util.Set because of the different
* identity constraints, i.e. two Graphs may be equal (isomorphic)
* even if the set of triples are not.
*
* Implementations MUST be immutable and throw respective exceptions, when
* add/remove-methods are called.
*
* @author reto
* @see org.apache.clerezza.rdf.core.impl.AbstractGraph
*/
public interface ImmutableGraph extends Graph {
/**
* Returns true if two graphs are isomorphic
*
* @return true if two graphs are isomorphic
*/
@Override
public boolean equals(Object obj);
/**
* Return the sum of the blank-nodes independent hashes of the triples.
* More precisely the hash of the triple is calculated as follows:
* (hash(subject) >> 1) ^ hash(hashCode) ^ (hash(hashCode) << 1)
* Where the hash-fucntion return the hashCode of the argument
* for grounded arguments and 0 otherwise.
*
* @return hash code
*/
@Override
public int hashCode();
}