com.shigengyu.hyperion.core.WorkflowContextXmlSerializer.java Source code

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Here is the source code for com.shigengyu.hyperion.core.WorkflowContextXmlSerializer.java

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/*******************************************************************************
 * Copyright 2013-2014 Gengyu Shi
 *
 * 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 com.shigengyu.hyperion.core;

import org.reflections.Reflections;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;

import com.shigengyu.hyperion.utils.ReflectionsHelper;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.annotations.XStreamAlias;
import com.thoughtworks.xstream.converters.basic.DateConverter;
import com.thoughtworks.xstream.io.xml.DomDriver;

public class WorkflowContextXmlSerializer implements WorkflowContextSerializer, BeanPostProcessor {

    protected XStream xStream = new XStream(new DomDriver());

    private final String dateTimeFormat;

    public WorkflowContextXmlSerializer(final String dateTimeFormat) {
        this.dateTimeFormat = dateTimeFormat;
        xStream.registerConverter(new DateConverter(dateTimeFormat, new String[0]));
        xStream.autodetectAnnotations(true);
    }

    @Override
    public <T extends WorkflowContext> T deserialize(final Class<T> clazz, final String input) {
        T workflowContext = null;
        try {
            Object deserializedObject = xStream.fromXML(input);
            if (deserializedObject == null) {
                return null;
            }
            workflowContext = clazz.cast(deserializedObject);

            // Initialize fields as default constructor will not be called when object is deserialized
            workflowContext.initializeFieldsOnDeserialization();

            return workflowContext;
        } catch (ClassCastException e) {
            if (workflowContext != null) {
                throw new WorkflowContextException("Unable to cast workflow context of type ["
                        + workflowContext.getClass().getName() + "] to [" + clazz.getName() + "]");
            } else {
                throw new WorkflowContextException(e);
            }
        }
    }

    @Override
    public WorkflowContextSerializer getCloned() {
        return new WorkflowContextXmlSerializer(dateTimeFormat);
    }

    public void initialize(final String... packageNames) {
        final Reflections reflections = ReflectionsHelper.createReflections(packageNames);
        for (final Class<?> clazz : reflections.getSubTypesOf(WorkflowContext.class)) {
            try {
                Class.forName(clazz.getName());
            } catch (final ClassNotFoundException e) {
            }
        }
    }

    @Override
    public Object postProcessAfterInitialization(final Object bean, final String beanName) throws BeansException {
        return bean;
    }

    @Override
    public Object postProcessBeforeInitialization(final Object bean, final String beanName) throws BeansException {
        if (bean.getClass().isAnnotationPresent(XStreamAlias.class)) {
            final XStreamAlias alias = bean.getClass().getAnnotation(XStreamAlias.class);
            xStream.alias(alias.value(), bean.getClass());
        }

        return bean;
    }

    @Override
    public String serialize(final WorkflowContext workflowContext) {
        return xStream.toXML(workflowContext);
    }
}