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/*
 * ====================================================================
 * 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
 * .
 *
 */

package com.facebook.presto.jdbc.internal.apache.http.entity;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import com.facebook.presto.jdbc.internal.apache.http.HttpEntity;
import com.facebook.presto.jdbc.internal.apache.http.util.Args;

/**
 * A wrapping entity that buffers it content if necessary.
 * The buffered entity is always repeatable.
 * If the wrapped entity is repeatable itself, calls are passed through.
 * If the wrapped entity is not repeatable, the content is read into a
 * buffer once and provided from there as often as required.
 *
 * @since 4.0
 */
public class BufferedHttpEntity extends HttpEntityWrapper {

    private final byte[] buffer;

    /**
     * Creates a new buffered entity wrapper.
     *
     * @param entity   the entity to wrap, not null
     * @throws IllegalArgumentException if wrapped is null
     */
    public BufferedHttpEntity(final HttpEntity entity) throws IOException {
        super(entity);
        if (!entity.isRepeatable() || entity.getContentLength() < 0) {
            final ByteArrayOutputStream out = new ByteArrayOutputStream();
            entity.writeTo(out);
            out.flush();
            this.buffer = out.toByteArray();
        } else {
            this.buffer = null;
        }
    }

    @Override
    public long getContentLength() {
        if (this.buffer != null) {
            return this.buffer.length;
        } else {
            return super.getContentLength();
        }
    }

    @Override
    public InputStream getContent() throws IOException {
        if (this.buffer != null) {
            return new ByteArrayInputStream(this.buffer);
        } else {
            return super.getContent();
        }
    }

    /**
     * Tells that this entity does not have to be chunked.
     *
     * @return  {@code false}
     */
    @Override
    public boolean isChunked() {
        return (buffer == null) && super.isChunked();
    }

    /**
     * Tells that this entity is repeatable.
     *
     * @return  {@code true}
     */
    @Override
    public boolean isRepeatable() {
        return true;
    }


    @Override
    public void writeTo(final OutputStream outstream) throws IOException {
        Args.notNull(outstream, "Output stream");
        if (this.buffer != null) {
            outstream.write(this.buffer);
        } else {
            super.writeTo(outstream);
        }
    }


    // non-javadoc, see interface HttpEntity
    @Override
    public boolean isStreaming() {
        return (buffer == null) && super.isStreaming();
    }

} // class BufferedHttpEntity