jena-arq/src/main/java/org/apache/jena/sparql/core/BasicPattern.java

/*
 * 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.jena.sparql.core ;

import java.util.ArrayList ;
import java.util.Iterator ;
import java.util.List ;

import org.apache.jena.atlas.io.IndentedLineBuffer ;
import org.apache.jena.graph.Triple ;
import org.apache.jena.sparql.serializer.SerializationContext ;
import org.apache.jena.sparql.sse.SSE ;
import org.apache.jena.sparql.sse.writers.WriterNode ;
import org.apache.jena.sparql.util.Iso ;
import org.apache.jena.sparql.util.NodeIsomorphismMap ;

/**
 * A class whose purpose is to give a name to a collection of triples. Reduces the use of
 * bland "List" in APIs (Java 1.4)
 */

public class BasicPattern implements Iterable<Triple> {
    private List<Triple> triples ;

    public BasicPattern() {
        this(new ArrayList<Triple>()) ;
    }

    public BasicPattern(BasicPattern other) {
        this() ;
        // Copy.
        triples.addAll(other.triples) ;
    }

    private BasicPattern(List<Triple> triples) {
        this.triples = triples ;
    }

    /**
     * Wrap a list of triples up as a BasicPattern. Changing the list, changes the
     * BasicPattern
     */
    public static BasicPattern wrap(List<Triple> triples) {
        return new BasicPattern(triples) ;
    }

    public void add(Triple t) {
        triples.add(t) ;
    }

    public void addAll(BasicPattern other) {
        triples.addAll(other.triples) ;
    }

    public void add(int i, Triple t) {
        triples.add(i, t) ;
    }

    public Triple get(int i) {
        return triples.get(i) ;
    }

    @Override
    public Iterator<Triple> iterator() {
        return triples.listIterator() ;
    }

    public int size() {
        return triples.size() ;
    }

    public boolean isEmpty() {
        return triples.isEmpty() ;
    }

    public List<Triple> getList() {
        return triples ;
    }

    @Override
    public int hashCode() {
        return triples.hashCode() ;
    }

    @Override
    public boolean equals(Object other) {
        if ( this == other )
            return true ;
        if ( !(other instanceof BasicPattern) )
            return false ;
        BasicPattern bp = (BasicPattern)other ;
        return triples.equals(bp.triples) ;
    }

    public boolean equiv(BasicPattern other, NodeIsomorphismMap isoMap) {
        if ( this.triples.size() != other.triples.size() )
            return false ;

        for ( int i = 0 ; i < this.triples.size() ; i++ ) {
            Triple t1 = get(i) ;
            Triple t2 = other.get(i) ;

            if ( !Iso.tripleIso(t1, t2, isoMap) )
                return false ;
        }
        return true ;
    }

    @Override
    public String toString() {
        IndentedLineBuffer out = new IndentedLineBuffer() ;
        SerializationContext sCxt = SSE.sCxt(SSE.getPrefixMapString()) ;

        boolean first = true ;
        for ( Triple t : triples ) {
            if ( !first )
                out.print("\n") ;
            else
                first = false ;
            // Adds (triple ...)
            // SSE.write(buff.getIndentedWriter(), t) ;
            out.print("(") ;
            WriterNode.outputPlain(out, t, sCxt) ;
            out.print(")") ;
        }
        out.flush() ;
        return out.toString() ;
    }
}