jena-core/src/main/java/org/apache/jena/mem/NodeToTriplesMapMem.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.mem;

import java.util.function.Predicate;

import org.apache.jena.graph.Node ;
import org.apache.jena.graph.Triple ;
import org.apache.jena.graph.Triple.Field ;
import org.apache.jena.shared.JenaException ;
import org.apache.jena.util.iterator.ExtendedIterator ;
import org.apache.jena.util.iterator.NullIterator ;

public class NodeToTriplesMapMem extends NodeToTriplesMapBase
    {    
    public NodeToTriplesMapMem( Field indexField, Field f2, Field f3 )
       { super( indexField, f2, f3 ); }
    
    /**
        Add <code>t</code> to this NTM; the node <code>o</code> <i>must</i>
        be the index node of the triple. Answer <code>true</code> iff the triple
        was not previously in the set, ie, it really truly has been added. 
    */
    @Override public boolean add( Triple t ) 
       {
       Object o = getIndexField( t );

       // Feb 2016 : no measurable difference.
       //TripleBunch s = bunchMap.getOrSet(o, (k)->new ArrayBunch()) ;
       
       TripleBunch s = bunchMap.get( o );
       if (s == null) bunchMap.put( o, s = new ArrayBunch() );
       if (s.contains( t ))
           return false;
       else
           {
           if (s.size() == 9 && s instanceof ArrayBunch)
               bunchMap.put( o, s = new HashedTripleBunch( s ) );
           s.add( t );
           size += 1; 
           return true; 
           } 
       }
    
    /**
        Remove <code>t</code> from this NTM. Answer <code>true</code> iff the 
        triple was previously in the set, ie, it really truly has been removed. 
    */
    @Override public boolean remove( Triple t )
       { 
       Object o = getIndexField( t );
       TripleBunch s = bunchMap.get( o );
       if (s == null || !s.contains( t ))
           return false;
       else
           {
           s.remove( t );
           size -= 1;
           if (s.size() == 0) bunchMap.remove( o );
           return true;
        } 
    }
    
    /**
        Answer an iterator over all the triples in this NTM which have index node
        <code>o</code>.
    */
    @Override public ExtendedIterator<Triple> iterator( Object o, HashCommon.NotifyEmpty container )
       {
       TripleBunch s = bunchMap.get( o );
       return s == null ? NullIterator.<Triple>instance() : s.iterator( container );
       }

    public ExtendedIterator<Triple> iterateAll(Triple pattern)
        {
        Predicate<Triple> filter = indexField.filterOn(pattern)
                .and(f2.filterOn(pattern)).and(f3.filterOn(pattern));
        return iterateAll().filterKeep(filter);
        }
    
    public class NotifyMe implements HashCommon.NotifyEmpty
        {
        protected final Object key;
        
        public NotifyMe( Object key )
            { this.key = key; }
        
        // TODO fix the way this interacts (badly) with iteration and CMEs.
        @Override
        public void emptied()
            { if (false) throw new JenaException( "BOOM" ); /* System.err.println( ">> OOPS" ); */ bunchMap.remove( key ); }
        }
    
    /**
        Answer true iff this NTM contains the concrete triple <code>t</code>.
    */
    @Override public boolean contains( Triple t )
       { 
       TripleBunch s = bunchMap.get( getIndexField( t ) );
       return s == null ? false :  s.contains( t );
       }    
    
    @Override public boolean containsBySameValueAs( Triple t )
       { 
       TripleBunch s = bunchMap.get( getIndexField( t ) );
       return s == null ? false :  s.containsBySameValueAs( t );
       }
    
    /**
        Answer an iterator over all the triples in this NTM which match
        <code>pattern</code>. The index field of this NTM is guaranteed
        concrete in the pattern.
    */
    @Override public ExtendedIterator<Triple> iterator( Node index, Node n2, Node n3 )
       {
       Object indexValue = index.getIndexingValue();
       TripleBunch s = bunchMap.get( indexValue );
//       System.err.println( ">> ntmf::iterator: " + (s == null ? (Object) "None" : s.getClass()) );
       if (s == null) return NullIterator.<Triple>instance();
           var filter = FieldFilter.filterOn(f2, n2, f3, n3);
           return filter.hasFilter()
               ? s.iterator( new NotifyMe( indexValue ) ).filterKeep( filter.getFilter() )
               : s.iterator( new NotifyMe( indexValue ) );
       }

        protected TripleBunch get( Object index )
        { return bunchMap.get( index ); }
    
    /**
     Answer an iterator over all the triples that are indexed by the item <code>y</code>.
        Note that <code>y</code> need not be a Node (because of indexing values).
    */
    @Override public ExtendedIterator<Triple> iteratorForIndexed( Object y )
        { return get( y ).iterator();  }
    }