LargeBinaryDataMessageBodyWriter.java

/**
 * Copyright (C) 2011-2015 The XDocReport Team <xdocreport@googlegroups.com>
 *
 * All rights reserved.
 *
 * Permission is hereby granted, free  of charge, to any person obtaining
 * a  copy  of this  software  and  associated  documentation files  (the
 * "Software"), to  deal in  the Software without  restriction, including
 * without limitation  the rights to  use, copy, modify,  merge, publish,
 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
 * permit persons to whom the Software  is furnished to do so, subject to
 * the following conditions:
 *
 * The  above  copyright  notice  and  this permission  notice  shall  be
 * included in all copies or substantial portions of the Software.
 *
 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package fr.opensagres.xdocreport.remoting.resources.services.jaxrs;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;

import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.MessageBodyWriter;
import javax.ws.rs.ext.Provider;

import fr.opensagres.xdocreport.remoting.resources.domain.BinaryData;
import fr.opensagres.xdocreport.remoting.resources.domain.LargeBinaryData;

/**
 * {@link MessageBodyWriter} that streams an {@link BinaryData} object in an Http response.
 * <p>
 * To allow streaming the binday data is directly sent inside the Http body and the other attributes are passed as http
 * header (it avoids to use MultiPart encoding)
 * 
 * @author <a href="mailto:tdelprat@nuxeo.com">Tiry</a>
 */
@Provider
public class LargeBinaryDataMessageBodyWriter
    implements MessageBodyWriter<LargeBinaryData>
{

    public boolean isWriteable( Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType )
    {
        return LargeBinaryData.class.isAssignableFrom( type );
    }

    public long getSize( LargeBinaryData t, Class<?> type, Type genericType, Annotation[] annotations,
                         MediaType mediaType )
    {
        long n = t.getLength();
        // allow Streaming if we don't know the size of the Binary Data
        return n <= 0 ? -1 : n;
    }

    public void writeTo( LargeBinaryData t, Class<?> type, Type genericType, Annotation[] annotations,
                         MediaType mediaType, MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream )
        throws IOException, WebApplicationException
    {
        InputStream content = t.getContent();
        httpHeaders.add( "Content-Disposition", "attachement;filename=" + t.getFileName() );
        if (!httpHeaders.containsKey("Content-Type")) {
        	httpHeaders.add( "Content-Type", t.getMimeType() );	
        }
        httpHeaders.add( "X-resourceId", t.getResourceId() );
        copyLarge( content, entityStream );
        entityStream.flush();
    }

    /**
     * The default buffer size to use.
     */
    private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;

    private long copyLarge( InputStream input, OutputStream output )
        throws IOException
    {
        byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
        long count = 0;
        int n = 0;
        while ( -1 != ( n = input.read( buffer ) ) )
        {
            output.write( buffer, 0, n );
            count += n;
        }
        return count;
    }

}