org.spout.api.protocol.builder.GenericMessage.java Source code

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Here is the source code for org.spout.api.protocol.builder.GenericMessage.java

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/*
 * This file is part of Spout.
 *
 * Copyright (c) 2011 Spout LLC <http://www.spout.org/>
 * Spout is licensed under the Spout License Version 1.
 *
 * Spout is free software: you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option)
 * any later version.
 *
 * In addition, 180 days after any changes are published, you can use the
 * software, incorporating those changes, under the terms of the MIT license,
 * as described in the Spout License Version 1.
 *
 * Spout 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 Lesser General Public License for
 * more details.
 *
 * You should have received a copy of the GNU Lesser General Public License,
 * the MIT license and the Spout License Version 1 along with this program.
 * If not, see <http://www.gnu.org/licenses/> for the GNU Lesser General Public
 * License and see <http://spout.in/licensev1> for the full license, including
 * the MIT license.
 */
package org.spout.api.protocol.builder;

import java.io.IOException;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;

import org.spout.api.Platform;
import org.spout.api.Spout;
import org.spout.api.protocol.Message;
import org.spout.api.protocol.MessageCodec;

public abstract class GenericMessage<T extends Message> extends MessageCodec<T> implements Message {
    protected ByteBuf buffer;

    public GenericMessage(Class<T> clazz, int opcode) {
        super(clazz, opcode);
    }

    /**
     * Gets the field root for this message.  This should be a static final unchanging array.
     */
    public abstract CompoundMessageField getFieldRoot();

    public CompoundMessageField getToClientFieldRoot() {
        return getFieldRoot();
    }

    public CompoundMessageField getToServerFieldRoot() {
        return getFieldRoot();
    }

    /**
     * Gets the field loop up table for the message
     */
    public abstract int[] getFieldLoopup();

    @SuppressWarnings({ "unchecked", "hiding" })
    public <T> T get(FieldRef<T> ref) {
        setupBuffer(ref);

        CompoundMessageField f = getFieldRoot();

        return (T) f.read(this.buffer);
    }

    public long getLong(FieldRef<Long> ref) {
        setupBuffer(ref);

        CompoundMessageField f = getFieldRoot();

        return f.readLong(this.buffer);
    }

    public int getInt(FieldRef<Integer> ref) {
        setupBuffer(ref);

        CompoundMessageField f = getFieldRoot();

        return f.readInt(this.buffer);
    }

    public short getShort(FieldRef<Integer> ref) {
        setupBuffer(ref);

        CompoundMessageField f = getFieldRoot();

        return f.readShort(this.buffer);
    }

    public byte getByte(FieldRef<Byte> ref) {
        setupBuffer(ref);

        CompoundMessageField f = getFieldRoot();

        return f.readByte(this.buffer);
    }

    public short getUnsignedByte(FieldRef<Short> ref) {
        setupBuffer(ref);

        CompoundMessageField f = getFieldRoot();

        return f.readUnsignedByte(this.buffer);
    }

    private void setupBuffer(FieldRef<?> ref) {
        int index = ref.getIndex();
        this.buffer.readerIndex(getFieldLoopup()[index]);
    }

    @Override
    public ByteBuf encode(T message) throws IOException {
        return this.buffer;
    }

    @Override
    @SuppressWarnings("unchecked")
    public T decode(ByteBuf b) throws IOException {
        CompoundMessageField root = Spout.getPlatform() == Platform.CLIENT ? getToClientFieldRoot()
                : getToServerFieldRoot();
        int start = b.readerIndex();
        int fieldCount = root.getSubFieldCount();
        int[] indexArray = new int[fieldCount];
        int length = root.skip(b, indexArray);
        this.buffer = Unpooled.buffer(length);
        b.getBytes(start, this.buffer, 0, length);
        return (T) this;
    }
}