/*
 * Copyright 2014 TORCH GmbH
 *
 * 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.
 */

package org.graylog2.gelfclient.encoder;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToMessageEncoder;

import java.io.ByteArrayOutputStream;
import java.util.List;
import java.util.zip.GZIPOutputStream;

/**
 * @author Bernd Ahlers <bernd@torch.sh>
 */
public class GelfCompressionEncoder extends MessageToMessageEncoder<ByteBuf> {
    @Override
    protected void encode(ChannelHandlerContext ctx, ByteBuf msg, List<Object> out) throws Exception {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        GZIPOutputStream stream = new GZIPOutputStream(bos);

        stream.write(msg.array());
        stream.finish();
        stream.close();

        out.add(Unpooled.wrappedBuffer(bos.toByteArray()));

        bos.close();
    }
}

/*
 * Copyright 2014 TORCH GmbH
 *
 * 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.
 */

package org.graylog2.gelfclient.encoder;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToMessageEncoder;

import java.io.ByteArrayOutputStream;
import java.util.List;
import java.util.zip.GZIPOutputStream;

/**
 * @author Bernd Ahlers <bernd@torch.sh>
 */
public class GelfCompressionEncoder extends MessageToMessageEncoder<ByteBuf> {
    @Override
    protected void encode(ChannelHandlerContext ctx, ByteBuf msg, List<Object> out) throws Exception {
        try (final ByteArrayOutputStream bos = new ByteArrayOutputStream();
             final GZIPOutputStream stream = new GZIPOutputStream(bos)) {

            stream.write(msg.array());
            stream.finish();

            out.add(Unpooled.wrappedBuffer(bos.toByteArray()));
        }
    }
}

Use try-with-resources in GelfCompressionEncoder