/*
 * (c) Copyright 2009 Hewlett-Packard Development Company, LP
 * All rights reserved.
 * [See end of file]
 */

package migrate.lib.tuple;

import java.util.Arrays;
import java.util.List;

import org.openjena.atlas.lib.ColumnMap;
import org.openjena.atlas.lib.Lib;
import org.openjena.atlas.lib.NotImplemented;

/** Tuples - use less space by specific implementations for 
 *  various sizes.  Saves the array overhead of 3 slots.  
 *  And 3 slots for two items might amount to a lot of space.
 */
public abstract class ZTuple<T>
{
    static final int NulItemHashCode = 3 ;

    public abstract T get(int idx) ;
    // Immutable
    // public abstract T set(int idx, T item) ;

    public List<T> asList()
    {
        return Arrays.asList(tuple()) ;
    }
    
    public T[] tuple() 
    {
        int N = size() ;
        @SuppressWarnings("unchecked")
        T[] array = (T[])new Object[N] ;
        for (int i = 0; i < N; i++)
            array[i] = get(i) ;
        return array ;
    }

    /** Return a tuple with the column mapping applied */
    public ZTuple<T> map(ColumnMap colMap)
    {
        //return colMap.map(this) ;
        throw new NotImplemented("Tuple.map") ; 
    }
    
    /** Return a tuple with the column mapping reversed */
    public ZTuple<T> unmap(ColumnMap colMap)
    {
        //return colMap.unmap(this) ;
        throw new NotImplemented("Tuple.unmap") ; 
    }
    
    public abstract int size() ;
    
    // Cache?
    @Override
    public int hashCode()
    { 
        int x = 99 ;
        for ( int i = 0; i < size() ; i++)
            x ^= get(i).hashCode() ;
        return x ;  
    }
    
    @Override
    public boolean equals(Object other) 
    {
        if ( this == other ) return true ;
        if ( ! ( other instanceof ZTuple<?> ) )
            return false ;
        ZTuple<?> x = (ZTuple<?>)other ;
        if ( x.size() != this.size() )
            return false ;
        return equalElements(x) ;
    }
        
    protected boolean equalElements(ZTuple<?> tuple)
    {
        for ( int i = 0 ; i < tuple.size() ; i++ )
        {
            Object obj1 = get(i) ;
            Object obj2 = tuple.get(i) ;
            if ( ! Lib.equal(obj1, obj2) )
                return false ;
        }
        return true ; 
    }
    
}

/*
 * (c) Copyright 2009 Hewlett-Packard Development Company, LP
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */