/*
 * Copyright 2016 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.redis;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelPipeline;
import io.netty.handler.codec.MessageAggregator;
import io.netty.util.internal.UnstableApi;

A ChannelHandler that aggregates an BulkStringHeaderRedisMessage and its following BulkStringRedisContents into a single FullBulkStringRedisMessage with no following BulkStringRedisContents. It is useful when you don't want to take care of RedisMessages whose transfer encoding is 'chunked'. Insert this handler after RedisDecoder in the ChannelPipeline: 
ChannelPipeline p = ...; ... p.addLast("encoder", new RedisEncoder()); p.addLast("decoder", new RedisDecoder()); p.addLast("aggregator", new RedisBulkStringAggregator());
...
p.addLast("handler", new HttpRequestHandler());
 Be aware that you need to have the RedisEncoder before the RedisBulkStringAggregator in the ChannelPipeline. /**
 * A {@link ChannelHandler} that aggregates an {@link BulkStringHeaderRedisMessage}
 * and its following {@link BulkStringRedisContent}s into a single {@link FullBulkStringRedisMessage}
 * with no following {@link BulkStringRedisContent}s.  It is useful when you don't want to take
 * care of {@link RedisMessage}s whose transfer encoding is 'chunked'.  Insert this
 * handler after {@link RedisDecoder} in the {@link ChannelPipeline}:
 * <pre>
 * {@link ChannelPipeline} p = ...;
 * ...
 * p.addLast("encoder", new {@link RedisEncoder}());
 * p.addLast("decoder", new {@link RedisDecoder}());
 * p.addLast("aggregator", <b>new {@link RedisBulkStringAggregator}()</b>);
 * ...
 * p.addLast("handler", new HttpRequestHandler());
 * </pre>
 * Be aware that you need to have the {@link RedisEncoder} before the {@link RedisBulkStringAggregator}
 * in the {@link ChannelPipeline}.
 */
@UnstableApi
public final class RedisBulkStringAggregator extends MessageAggregator<RedisMessage, BulkStringHeaderRedisMessage,
                                                                 BulkStringRedisContent, FullBulkStringRedisMessage> {

    
Creates a new instance.
/**
     * Creates a new instance.
     */
    public RedisBulkStringAggregator() {
        super(RedisConstants.REDIS_MESSAGE_MAX_LENGTH);
    }

    @Override
    protected boolean isStartMessage(RedisMessage msg) throws Exception {
        return msg instanceof BulkStringHeaderRedisMessage && !isAggregated(msg);
    }

    @Override
    protected boolean isContentMessage(RedisMessage msg) throws Exception {
        return msg instanceof BulkStringRedisContent;
    }

    @Override
    protected boolean isLastContentMessage(BulkStringRedisContent msg) throws Exception {
        return msg instanceof LastBulkStringRedisContent;
    }

    @Override
    protected boolean isAggregated(RedisMessage msg) throws Exception {
        return msg instanceof FullBulkStringRedisMessage;
    }

    @Override
    protected boolean isContentLengthInvalid(BulkStringHeaderRedisMessage start, int maxContentLength)
            throws Exception {
        return start.bulkStringLength() > maxContentLength;
    }

    @Override
    protected Object newContinueResponse(BulkStringHeaderRedisMessage start, int maxContentLength,
                                         ChannelPipeline pipeline) throws Exception {
        return null;
    }

    @Override
    protected boolean closeAfterContinueResponse(Object msg) throws Exception {
        throw new UnsupportedOperationException();
    }

    @Override
    protected boolean ignoreContentAfterContinueResponse(Object msg) throws Exception {
        throw new UnsupportedOperationException();
    }

    @Override
    protected FullBulkStringRedisMessage beginAggregation(BulkStringHeaderRedisMessage start, ByteBuf content)
            throws Exception {
        return new FullBulkStringRedisMessage(content);
    }
}