/**
 * Copyright 2007-2016, Kaazing Corporation. All rights reserved.
 *
 * 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.apache.mina.filter.stream;

import java.io.IOException;
import java.io.InputStream;

import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.filterchain.IoFilter;

/**
 * Filter implementation which makes it possible to write {@link InputStream}
 * objects directly using {@link IoSession#write(Object)}. When an
 * {@link InputStream} is written to a session this filter will read the bytes
 * from the stream into {@link IoBuffer} objects and write those buffers
 * to the next filter. When end of stream has been reached this filter will
 * call {@link IoFilter.NextFilter#messageSent(IoSession,WriteRequest)} using the original
 * {@link InputStream} written to the session and notifies
 * {@link org.apache.mina.core.future.WriteFuture} on the
 * original {@link org.apache.mina.core.write.WriteRequest}.
 * <p/>
 * This filter will ignore written messages which aren't {@link InputStream}
 * instances. Such messages will be passed to the next filter directly.
 * </p>
 * <p/>
 * NOTE: this filter does not close the stream after all data from stream
 * has been written. The {@link org.apache.mina.core.service.IoHandler} should take
 * care of that in its
 * {@link org.apache.mina.core.service.IoHandler#messageSent(IoSession,Object)}
 * callback.
 * </p>
 *
 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
 * @org.apache.xbean.XBean
 */
public class StreamWriteFilter extends AbstractStreamWriteFilter<InputStream> {

    @Override
    protected IoBuffer getNextBuffer(InputStream is) throws IOException {
        byte[] bytes = new byte[getWriteBufferSize()];

        int off = 0;
        int n = 0;
        while (off < bytes.length
                && (n = is.read(bytes, off, bytes.length - off)) != -1) {
            off += n;
        }

        if (n == -1 && off == 0) {
            return null;
        }

        IoBuffer buffer = IoBuffer.wrap(bytes, 0, off);

        return buffer;
    }
    
    @Override
    protected Class<InputStream> getMessageClass() {
        return InputStream.class;
    }

}
