# JacksonValueSerializer.java

    /*
     * Copyright (c) 2012, Paul Merlin. 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.qi4j.valueserialization.jackson;

    import com.fasterxml.jackson.core.JsonFactory;
    import com.fasterxml.jackson.core.JsonGenerator;
    import com.fasterxml.jackson.databind.MappingJsonFactory;
    import java.io.OutputStream;
    import org.qi4j.spi.value.ValueSerializerAdapter;

    /**
     * ValueSerializer producing Values state as JSON documents using Jackson.
     */
    public class JacksonValueSerializer
        extends ValueSerializerAdapter<JsonGenerator>
    {

        private final JsonFactory jsonFactory = new MappingJsonFactory();

        @Override
        protected JsonGenerator adaptOutput( OutputStream output )
            throws Exception
        {
            return jsonFactory.createGenerator( output );
        }

        @Override
        protected void onSerializationEnd( Object object, JsonGenerator output )
            throws Exception
        {
            output.close();
        }

        @Override
        protected void onArrayStart( JsonGenerator output )
            throws Exception
        {
            output.writeStartArray();
        }

        @Override
        protected void onArrayEnd( JsonGenerator output )
            throws Exception
        {
            output.writeEndArray();
        }

        @Override
        protected void onObjectStart( JsonGenerator output )
            throws Exception
        {
            output.writeStartObject();
        }

        @Override
        protected void onObjectEnd( JsonGenerator output )
            throws Exception
        {
            output.writeEndObject();
        }

        @Override
        protected void onFieldStart( JsonGenerator output, String fieldName )
            throws Exception
        {
            output.writeFieldName( fieldName );
        }

        @Override
        protected void onValue( JsonGenerator output, Object value )
            throws Exception
        {
            output.writeObject( value );
        }
    }