/**
 * 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.codec.serialization;

import java.io.NotSerializableException;
import java.io.Serializable;

import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.ProtocolEncoder;
import org.apache.mina.filter.codec.ProtocolEncoderAdapter;
import org.apache.mina.filter.codec.ProtocolEncoderOutput;

/**
 * A {@link ProtocolEncoder} which serializes {@link Serializable} Java objects
 * using {@link IoBuffer#putObject(Object)}.
 *
 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
 */
public class ObjectSerializationEncoder extends ProtocolEncoderAdapter {
    private int maxObjectSize = Integer.MAX_VALUE; // 2GB

    /**
     * Creates a new instance.
     */
    public ObjectSerializationEncoder() {
        // Do nothing
    }

    /**
     * Returns the allowed maximum size of the encoded object.
     * If the size of the encoded object exceeds this value, this encoder
     * will throw a {@link IllegalArgumentException}.  The default value
     * is {@link Integer#MAX_VALUE}.
     */
    public int getMaxObjectSize() {
        return maxObjectSize;
    }

    /**
     * Sets the allowed maximum size of the encoded object.
     * If the size of the encoded object exceeds this value, this encoder
     * will throw a {@link IllegalArgumentException}.  The default value
     * is {@link Integer#MAX_VALUE}.
     */
    public void setMaxObjectSize(int maxObjectSize) {
        if (maxObjectSize <= 0) {
            throw new IllegalArgumentException("maxObjectSize: "
                    + maxObjectSize);
        }

        this.maxObjectSize = maxObjectSize;
    }

    public void encode(IoSession session, Object message,
            ProtocolEncoderOutput out) throws Exception {
        if (!(message instanceof Serializable)) {
            throw new NotSerializableException();
        }

        IoBuffer buf = IoBuffer.allocate(64);
        buf.setAutoExpand(true);
        buf.putObject(message);

        int objectSize = buf.position() - 4;
        if (objectSize > maxObjectSize) {
            throw new IllegalArgumentException(
                    "The encoded object is too big: " + objectSize + " (> "
                            + maxObjectSize + ')');
        }

        buf.flip();
        out.write(buf);
    }
}
