com.intelligentsia.dowsers.entity.serializer.EntityMapper.java Source code

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Here is the source code for com.intelligentsia.dowsers.entity.serializer.EntityMapper.java

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/**
 *        Licensed to the Apache Software Foundation (ASF) under one
 *        or more contributor license agreements.  See the NOTICE file
 *        distributed with this work for additional information
 *        regarding copyright ownership.  The ASF licenses this file
 *        to you 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 com.intelligentsia.dowsers.entity.serializer;

import java.io.Reader;
import java.io.Writer;
import java.lang.reflect.Modifier;
import java.lang.reflect.Proxy;

import org.intelligentsia.dowsers.core.DowsersException;
import org.intelligentsia.dowsers.core.serializers.JacksonSerializer;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.intelligentsia.dowsers.entity.EntityProxy;
import com.intelligentsia.dowsers.entity.meta.MetaEntityContextProvider;

/**
 * EntityMapper is a base class to read and write entity.
 * 
 * @author <a href="mailto:jguibert@intelligents-ia.com" >Jerome Guibert</a>
 */
public class EntityMapper {

    private final ObjectMapper mapper;

    /**
     * Build a new instance of <code>EntityMapper</code>. You must call
     * {@link EntityMapper#initialize(MetaEntityContextProvider)} before using
     * this instance.
     */
    public EntityMapper() {
        this(JacksonSerializer.getMapper());
    }

    /**
     * Build a new instance of <code>EntityMapper</code>.
     * 
     * @param mapper
     *            You must call
     *            {@link EntityMapper#initialize(MetaEntityContextProvider)}
     *            before using this instance.
     */
    public EntityMapper(final ObjectMapper mapper) {
        super();
        this.mapper = mapper;
    }

    /**
     * Build a new instance of EntityMapper.java.
     * 
     * @param metaEntityContextProvider
     */
    public EntityMapper(final MetaEntityContextProvider metaEntityContextProvider) {
        this(JacksonSerializer.getMapper(), metaEntityContextProvider);
    }

    /**
     * Build a new instance of EntityMapper.java.
     * 
     * @param mapper
     * @param metaEntityContextProvider
     */
    public EntityMapper(final ObjectMapper mapper, final MetaEntityContextProvider metaEntityContextProvider) {
        super();
        this.mapper = mapper;
        initialize(metaEntityContextProvider);
    }

    public void initialize(final MetaEntityContextProvider metaEntityContextProvider) {
        this.mapper.registerModule(new EntityDowsersJacksonModule(metaEntityContextProvider));
    }

    /**
     * Method that can be used to serialize any Java value as JSON output, using
     * Writer provided.
     * 
     * @param writer
     * @param value
     * @throws DowsersException
     */
    public void writeValue(final Writer writer, final Object value) throws DowsersException {
        try {
            mapper.writeValue(writer, value);
        } catch (final Throwable e) {
            throw new DowsersException(e);
        }
    }

    /**
     * Method that can be used to parse JSON to specified Java value, using
     * reader provided.
     * 
     * @param reader
     * @param valueType
     * @return
     * @throws DowsersException
     */
    @SuppressWarnings("unchecked")
    public <T> T readValue(final Reader reader, final Class<T> valueType) throws DowsersException {
        if (valueType.isInterface() || Modifier.isAbstract(valueType.getModifiers())) {
            try {
                final EntityProxy entityProxy = mapper.readValue(reader, EntityProxy.class);
                return (T) Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(),
                        new Class[] { valueType, EntityProxyHandler.class }, entityProxy);
            } catch (final Throwable e) {
                throw new DowsersException(e);
            }
        }
        try {
            return mapper.readValue(reader, valueType);
        } catch (final Throwable e) {
            throw new DowsersException(e);
        }
    }
}