/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */
package org.apache.http.client.entity;

/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.zip.GZIPOutputStream;

import org.apache.http.Header;
import org.apache.http.HttpEntity;
import org.apache.http.entity.HttpEntityWrapper;
import org.apache.http.message.BasicHeader;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.Args;

/**
 * Wrapping entity that compresses content when {@link #writeTo writing}.
 *
 *
 * @since 4.0
 */
public class GzipCompressingEntity extends HttpEntityWrapper {

    private static final String GZIP_CODEC = "gzip";

    public GzipCompressingEntity(final HttpEntity entity) {
        super(entity);
    }

    @Override
    public Header getContentEncoding() {
        return new BasicHeader(HTTP.CONTENT_ENCODING, GZIP_CODEC);
    }

    @Override
    public long getContentLength() {
        return -1;
    }

    @Override
    public boolean isChunked() {
        // force content chunking
        return true;
    }

    @Override
    public InputStream getContent() throws IOException {
        throw new UnsupportedOperationException();
    }

    @Override
    public void writeTo(final OutputStream outStream) throws IOException {
        Args.notNull(outStream, "Output stream");
        final GZIPOutputStream gzip = new GZIPOutputStream(outStream);
        wrappedEntity.writeTo(gzip);
        // Only close output stream if the wrapped entity has been
        // successfully written out
        gzip.close();
    }

}
