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EMC Atmos Client for Java - provides REST access to object data on EMC platforms using the Atmos API.
There is a newer version: 3.2.1
/*
 * Copyright (c) 2013-2016, EMC Corporation.
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * + Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * + Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * + The name of EMC Corporation may not be used to endorse or promote
 *   products derived from this software without specific prior written
 *   permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package com.emc.atmos.api.jersey.provider;

import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.MessageBodyWriter;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;

/**
 * Base class to disable chunked encoding in requests by always specifying an accurate byte count in getSize().
 * Subclasses should provide a default constructor, which calls super() with an instance of the underlying writer
 * implementation to be wrapped.
 * 
 * XXX: this is inefficient and should be replaced by a different mechanism.  However, it is the simplest solution to
 * the apache client's insistence on using chunked encoding for all requests with a size of -1 and Jersey's insistence
 * on returning -1 from all message body providers (as well as not allowing users to override the content-length
 * header).
 */
public class MeasuredMessageBodyWriter implements MessageBodyWriter {
    protected MessageBodyWriter wrapped;
    private IOException delayedIOException;
    private WebApplicationException delayedWebAppException;

    public MeasuredMessageBodyWriter( MessageBodyWriter wrapped ) {
        this.wrapped = wrapped;
    }

    @Override
    public boolean isWriteable( Class type, Type genericType, Annotation[] annotations, MediaType mediaType ) {
        return wrapped.isWriteable( type, genericType, annotations, mediaType );
    }

    @Override
    public void writeTo( T t,
                         Class type,
                         Type genericType,
                         Annotation[] annotations,
                         MediaType mediaType,
                         MultivaluedMap httpHeaders,
                         OutputStream entityStream ) throws IOException, WebApplicationException {
        if ( delayedIOException != null ) throw delayedIOException;
        if ( delayedWebAppException != null ) throw delayedWebAppException;
        entityStream.write( getBuffer( t, type, genericType, annotations, mediaType, httpHeaders ) );
    }

    @Override
    public long getSize( T t, Class type, Type genericType, Annotation[] annotations, MediaType mediaType ) {
        try {
            return getBuffer( t, type, genericType, annotations, mediaType, null ).length;
        } catch ( IOException e ) {
            delayedIOException = e;
        } catch ( WebApplicationException e ) {
            delayedWebAppException = e;
        }
        return -1;
    }

    protected synchronized byte[] getBuffer( T t,
                                             Class type,
                                             Type genericType,
                                             Annotation[] annotations,
                                             MediaType mediaType,
                                             MultivaluedMap httpHeaders )
            throws IOException, WebApplicationException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        wrapped.writeTo( t, type, genericType, annotations, mediaType, httpHeaders, baos );
        return baos.toByteArray();
    }
}