/*
 * Copyright 2013 The Netty Project
 *
 * The Netty Project 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 io.netty.handler.codec.memcache;

import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelPipeline;
import io.netty.handler.codec.MessageAggregator;
import io.netty.handler.codec.memcache.binary.BinaryMemcacheRequestDecoder;
import io.netty.handler.codec.memcache.binary.BinaryMemcacheResponseEncoder;

/**
 * A {@link ChannelHandler} that aggregates an {@link MemcacheMessage}
 * and its following {@link MemcacheContent}s into a single {@link MemcacheMessage} with
 * no following {@link MemcacheContent}s.  It is useful when you don't want to take
 * care of memcache messages where the content comes along in chunks. Insert this
 * handler after a AbstractMemcacheObjectDecoder in the {@link ChannelPipeline}.
 * <p/>
 * For example, here for the binary protocol:
 * <p/>
 * <pre>
 * {@link ChannelPipeline} p = ...;
 * ...
 * p.addLast("decoder", new {@link BinaryMemcacheRequestDecoder}());
 * p.addLast("aggregator", <b>new {@link io.netty.handler.codec.memcache.binary.BinaryMemcacheObjectAggregator}(1048576)
 * </b>);
 * ...
 * p.addLast("encoder", new {@link BinaryMemcacheResponseEncoder}());
 * p.addLast("handler", new YourMemcacheRequestHandler());
 * </pre>
 */
public abstract class AbstractMemcacheObjectAggregator<H extends MemcacheMessage> extends
        MessageAggregator<MemcacheObject, H, MemcacheContent, FullMemcacheMessage> {

    protected AbstractMemcacheObjectAggregator(int maxContentLength) {
        super(maxContentLength);
    }

    @Override
    protected boolean isContentMessage(MemcacheObject msg) throws Exception {
        return msg instanceof MemcacheContent;
    }

    @Override
    protected boolean isLastContentMessage(MemcacheContent msg) throws Exception {
        return msg instanceof LastMemcacheContent;
    }

    @Override
    protected boolean isAggregated(MemcacheObject msg) throws Exception {
        return msg instanceof FullMemcacheMessage;
    }

    @Override
    protected boolean hasContentLength(H start) throws Exception {
        return false;
    }

    @Override
    protected long contentLength(H start) throws Exception {
        throw new UnsupportedOperationException();
    }

    @Override
    protected Object newContinueResponse(H start) throws Exception {
        return null;
    }
}
