org.mule.module.json.transformers.ObjectToJson.java Source code

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Here is the source code for org.mule.module.json.transformers.ObjectToJson.java

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/*
 * $Id$
 * --------------------------------------------------------------------------------------
 * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
 *
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */

package org.mule.module.json.transformers;

import org.mule.api.MuleMessage;
import org.mule.api.lifecycle.InitialisationException;
import org.mule.api.transformer.TransformerException;
import org.mule.module.json.filters.IsJsonFilter;
import org.mule.transformer.types.DataTypeFactory;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.io.IOException;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Converts a java object to a JSON encoded object that can be consumed by other languages such as
 * Javascript or Ruby.
 * <p/>
 * The returnClass for this transformer is always java.lang.String, there is no need to set this.
 */
public class ObjectToJson extends AbstractJsonTransformer {
    /**
     * logger used by this class
     */
    protected transient final Log logger = LogFactory.getLog(ObjectToJson.class);

    private Map<Class<?>, Class<?>> serializationMixins = new HashMap<Class<?>, Class<?>>();

    protected Class<?> sourceClass;

    private boolean handleException = false;

    private IsJsonFilter isJsonFilter = new IsJsonFilter();

    public ObjectToJson() {
        this.setReturnDataType(DataTypeFactory.JSON_STRING);
    }

    @Override
    public void initialise() throws InitialisationException {
        super.initialise();

        //restrict the handled types
        if (getSourceClass() != null) {
            sourceTypes.clear();
            registerSourceType(DataTypeFactory.create(getSourceClass()));
        }

        //Add shared mixins first
        for (Map.Entry<Class<?>, Class<?>> entry : getMixins().entrySet()) {
            getMapper().getSerializationConfig().addMixInAnnotations(entry.getKey(), entry.getValue());
        }

        for (Map.Entry<Class<?>, Class<?>> entry : serializationMixins.entrySet()) {
            getMapper().getSerializationConfig().addMixInAnnotations(entry.getKey(), entry.getValue());
        }
    }

    @Override
    public Object transformMessage(MuleMessage message, String outputEncoding) throws TransformerException {
        Object src = message.getPayload();
        if (src instanceof String && isJsonFilter.accept(src)) {
            //Nothing to transform
            return src;
        }

        // Checks if there's an exception
        if (message.getExceptionPayload() != null && this.isHandleException()) {
            if (logger.isDebugEnabled()) {
                logger.debug("Found exception with null payload");
            }
            src = this.getException(message.getExceptionPayload().getException());
        }

        StringWriter writer = new StringWriter();
        try {
            getMapper().writeValue(writer, src);
        } catch (IOException e) {
            throw new TransformerException(this, e);
        }

        if (returnType.getType().equals(byte[].class)) {
            try {
                return writer.toString().getBytes(outputEncoding);
            } catch (UnsupportedEncodingException uee) {
                throw new TransformerException(this, uee);
            }
        } else {
            return writer.toString();
        }
    }

    /**
     * The reason of having this is because the original exception object is way too
     * complex and it breaks JSON-lib.
     */
    private Exception getException(Throwable t) {
        Exception returnValue = null;
        List<Throwable> causeStack = new ArrayList<Throwable>();

        for (Throwable tempCause = t; tempCause != null; tempCause = tempCause.getCause()) {
            causeStack.add(tempCause);
        }

        for (int i = causeStack.size() - 1; i >= 0; i--) {
            Throwable tempCause = causeStack.get(i);

            // There is no cause at the very root
            if (i == causeStack.size()) {
                returnValue = new Exception(tempCause.getMessage());
                returnValue.setStackTrace(tempCause.getStackTrace());
            } else {
                returnValue = new Exception(tempCause.getMessage(), returnValue);
                returnValue.setStackTrace(tempCause.getStackTrace());
            }
        }

        return returnValue;
    }

    public boolean isHandleException() {
        return this.handleException;
    }

    public void setHandleException(boolean handleException) {
        this.handleException = handleException;
    }

    public Class<?> getSourceClass() {
        return sourceClass;
    }

    public void setSourceClass(Class<?> sourceClass) {
        this.sourceClass = sourceClass;
    }

    public Map<Class<?>, Class<?>> getSerializationMixins() {
        return serializationMixins;
    }

    public void setSerializationMixins(Map<Class<?>, Class<?>> serializationMixins) {
        this.serializationMixins = serializationMixins;
    }
}