/*
* Copyright 2015 Red Hat, Inc. and/or its affiliates.
*
* 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.jbpm.process.workitem.parser;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.HashMap;
import java.util.Map;
import javax.xml.bind.JAXB;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import org.jbpm.process.workitem.AbstractLogOrThrowWorkItemHandler;
import org.kie.api.runtime.process.WorkItem;
import org.kie.api.runtime.process.WorkItemManager;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
/**
* WorkItemHandler that is capable of parsing String to objects and vice-versa. Currently supports only two formats
* <ul>
* <li>XML</li>
* <li>JSON</li>
* </ul>
* Here is the list of supported parameters:
* <ul>
* <li>Input - The input data. If you provide a string, the parser will try to parse the string to an object of type Type and format Format (see below), if not, it will try to parse the object to a String of format Format. It is a required parameter;</li>
* <li>Format - It is a required parameter that can have the values JSON or XML;</li>
* <li>Result - The result is an output parameter that will be a string if you provide an Input object that is not of String type; and an object of type Type if you provide an Input object of type String.</li>
* <li>Type - The FQN of the object type (for example com.acme.Customer)</li>
* </ul>
*
* Providing these parameters correctly is enough to use the parser task. Please bear in mind that it uses JAXB to parse the object, so it must have the @XmlRootElement annotation.
*
*
*/
public class ParserWorkItemHandler extends AbstractLogOrThrowWorkItemHandler {
public static final String JSON = "JSON";
public static final String XML = "XML";
/**
* Only supports JSON or XML.
*/
public static final String FORMAT = "Format";
/**
* The target object type full qualified name (com.acme.Customer)
*
*/
public static final String TYPE = "Type";
/**
* The input object of type TYPE or String (if you set toObject)
*/
public static final String INPUT = "Input";
/**
* The resulting object or String (if toObject is false it will be a
* String).
*/
public static final String RESULT = "Result";
private ClassLoader cl;
public ParserWorkItemHandler() {
this.cl = this.getClass().getClassLoader();
}
public ParserWorkItemHandler(ClassLoader cl) {
this.cl = cl;
}
public void abortWorkItem(WorkItem wi, WorkItemManager wim) {
// no-op
}
public void executeWorkItem(WorkItem wi, WorkItemManager wim) {
Object input;
Object result = null;
boolean toObject;
Map<String, Object> results = new HashMap<String, Object>();
try {
String format = wi.getParameter(FORMAT).toString();
Class<?> type = null;
input = wi.getParameter(INPUT);
toObject = input instanceof String;
if (toObject) {
try {
String typeStr = wi.getParameter(TYPE).toString();
type = cl.loadClass(typeStr);
} catch (Exception e) {
throw new RuntimeException("Could not load the provided type. The parameter " + TYPE +
" is required when parsing from String to Object. Please provide the full qualified name of the target object class.", e);
}
}
if (JSON.equals(format.toUpperCase())) {
try {
result = toObject ? convertJSONToObject(input.toString(), type) : convertToJSON(input);
} catch (Exception e) {
throw new RuntimeException("Error parsing to JSON. Check the input format or the output object",e);
}
} else if (XML.equals(format.toUpperCase())) {
try {
result = toObject ? convertXMLToObject(input.toString(), type)
: convertToXML(input);
} catch (JAXBException e) {
throw new RuntimeException("Error parsing to XML. Check the input format or the output object", e);
}
}
results.put(RESULT, result);
wim.completeWorkItem(wi.getId(), results);
} catch (Exception e) {
handleException(e);
}
}
protected Object convertXMLToObject(String input, Class<?> type) {
return JAXB.unmarshal(new StringReader(input), type);
}
protected String convertToXML(Object input) throws JAXBException {
StringWriter result = new StringWriter();
JAXBContext jaxbContext = JAXBContext.newInstance(input.getClass());
Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, false);
jaxbMarshaller.marshal(input, result);
return result.toString();
}
protected Object convertJSONToObject(String input, Class<?> type) throws JsonMappingException, IOException {
return new ObjectMapper().readValue(input, type);
}
protected Object convertToJSON(Object input) throws JsonMappingException, IOException {
return new ObjectMapper().writeValueAsString(input);
}
}