/*

 * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

import java.nio.ByteBuffer;

import java.util.Objects;

import java.util.function.Supplier;

public class ByteBufferReference  implements Supplier<ByteBuffer> {

    private ByteBuffer buffer;

    private final ByteBufferPool pool;

    public static ByteBufferReference of(ByteBuffer buffer) {

        return of(buffer, null);

    }

    public static ByteBufferReference of(ByteBuffer buffer, ByteBufferPool pool) {

        Objects.requireNonNull(buffer);

        return new ByteBufferReference(buffer, pool);

    }

    public static ByteBuffer[] toBuffers(ByteBufferReference... refs) {

        ByteBuffer[] bufs = new ByteBuffer[refs.length];

        for (int i = 0; i < refs.length; i++) {

            bufs[i] = refs[i].get();

        }

        return bufs;

    }

    public static ByteBufferReference[] toReferences(ByteBuffer... buffers) {

        ByteBufferReference[] refs = new ByteBufferReference[buffers.length];

        for (int i = 0; i < buffers.length; i++) {

            refs[i] = of(buffers[i]);

        }

        return refs;

    }

    public static void clear(ByteBufferReference[] refs) {

        for(ByteBufferReference ref : refs) {

            ref.clear();

        }

    }

    private ByteBufferReference(ByteBuffer buffer, ByteBufferPool pool) {

        this.buffer = buffer;

        this.pool = pool;

    }

    @Override

    public ByteBuffer get() {

        ByteBuffer buf = this.buffer;

        assert buf!=null : "getting ByteBuffer after clearance";

        return buf;

    }

    public void clear() {

        ByteBuffer buf = this.buffer;

        assert buf!=null : "double ByteBuffer clearance";

        this.buffer = null;

        if (pool != null) {

            pool.release(buf);

        }

    }

}