/*
 * Copyright (c) 2004-2007 The Trustees of Indiana University and Indiana
 *                         University Research and Technology
 *                         Corporation.  All rights reserved.
 * Copyright (c) 2004-2005 The University of Tennessee and The University
 *                         of Tennessee Research Foundation.  All rights
 *                         reserved.
 * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart, 
 *                         University of Stuttgart.  All rights reserved.
 * Copyright (c) 2004-2005 The Regents of the University of California.
 *                         All rights reserved.
 * $COPYRIGHT$
 * 
 * Additional copyrights may follow
 * 
 * $HEADER$
 */
/*
 * This file is almost a complete re-write for Open MPI compared to the
 * original mpiJava package. Its license and copyright are listed below.
 * See <path to ompi/mpi/java/README> for more information.
 */
/*
    Licensed 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.
*/
/*
 * File         : Op.java
 * Author       : Xinying Li, Sang LIm
 * Created      : Thu Apr  9 12:22:15 1998
 * Revision     : $Revision: 1.11 $
 * Updated      : $Date: 2003/01/16 16:39:34 $
 * Copyright: Northeast Parallel Architectures Center
 *            at Syracuse University 1998
 */

package mpi;

import java.nio.*;

/**
 * This class represents {@code MPI_Op}.
 */
public final class Op implements Freeable
{
protected final UserFunction uf;
private boolean commute;
private Datatype datatype;
protected long handle;

static
{
    init();
}

private static native void init();

protected Op(int type)
{
    getOp(type);
    uf = null;
    commute = true;
}

private native void getOp(int type);

/**
 * Bind a user-defined global reduction operation to an {@code Op} object.
 * <p>Java binding of the MPI operation {@code MPI_OP_CREATE}.
 * @param function user defined function
 * @param commute  {@code true} if commutative, {@code false} otherwise
 */
public Op(UserFunction function, boolean commute)
{
    handle = 0; // When JNI code gets the handle it will be initialized.
    uf = function;
    this.commute = commute;
}

protected void setDatatype(Datatype t)
{
    datatype = t;
}

protected void call(Object invec, Object inoutvec, int count)
    throws MPIException
{
    if(datatype.baseType == Datatype.BOOLEAN)
    {
        uf.call(invec, inoutvec, count, datatype);
    }
    else
    {
        uf.call(((ByteBuffer)invec).order(ByteOrder.nativeOrder()),
                ((ByteBuffer)inoutvec).order(ByteOrder.nativeOrder()),
                count, datatype);
    }
}

/**
 * Test if the operation is conmutative.
 * <p>Java binding of the MPI operation {@code MPI_OP_COMMUTATIVE}.
 * @return {@code true} if commutative, {@code false} otherwise
 */
public boolean isCommutative()
{
    return commute;
}

/**
 * Java binding of the MPI operation {@code MPI_OP_FREE}.
 * @throws MPIException Signals that an MPI exception of some sort has occurred.
 */
@Override public native void free() throws MPIException;

/**
 * Test if operation object is null.
 * @return true if the operation object is null, false otherwise
 */
public native boolean isNull();

} // Op
