[JBPM-4708] Add a Parser service to Service Repository

jbpm-workitems/src/main/java/org/jbpm/process/workitem/parser/ParserWorkItemHandler.java

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+/*
+ * Copyright 2015 JBoss Inc
+ *
+ * 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);
+	}
+}

jbpm-workitems/src/test/java/org/jbpm/process/workitem/parser/ParserWorkItemHandlerTest.java

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+/*
+ * Copyright 2015 JBoss Inc
+ *
+ * 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 static org.junit.Assert.assertEquals;
+
+import java.util.Map;
+
+import org.drools.core.process.instance.impl.WorkItemImpl;
+import org.junit.Before;
+import org.junit.Test;
+import org.kie.api.runtime.process.WorkItem;
+import org.kie.api.runtime.process.WorkItemHandler;
+import org.kie.api.runtime.process.WorkItemManager;
+
+public class ParserWorkItemHandlerTest {
+
+	final int AGE = 27;
+	final String NAME = "William";
+	final String PERSON_XML = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><person><age>"
+			+ AGE + "</age><name>" + NAME + "</name></person>";
+	final String PERSON_JSON = "{\"name\":\"" + NAME + "\",\"age\":" + AGE
+			+ "}";
+
+	ParserWorkItemHandler handler;
+
+	@Before
+	public void init() {
+		handler = new ParserWorkItemHandler();
+	}
+
+	@Test
+	public void testXmlToObject() {
+		WorkItemImpl workItem = new WorkItemImpl();
+		workItem.setParameter(ParserWorkItemHandler.INPUT, PERSON_XML);
+		workItem.setParameter(ParserWorkItemHandler.FORMAT, ParserWorkItemHandler.XML);
+		workItem.setParameter(ParserWorkItemHandler.TYPE,
+				"org.jbpm.process.workitem.parser.Person");
+		handler.executeWorkItem(workItem, new TestWorkItemManager(workItem));
+		Person result = (Person) workItem.getResult(ParserWorkItemHandler.RESULT);
+		assertEquals(AGE, result.getAge());
+		assertEquals(NAME, result.getName());
+	}
+
+	@Test
+	public void testObjectToXml() {
+		Person p = new Person(NAME, AGE);
+		WorkItemImpl workItem = new WorkItemImpl();
+		workItem.setParameter(ParserWorkItemHandler.INPUT, p);
+		workItem.setParameter(ParserWorkItemHandler.FORMAT, ParserWorkItemHandler.XML);
+		handler.executeWorkItem(workItem, new TestWorkItemManager(workItem));
+		String result = (String) workItem.getResult(ParserWorkItemHandler.RESULT);
+		assertEquals(PERSON_XML, result);
+	}
+
+	@Test
+	public void testJsonToObject() {
+		WorkItemImpl workItem = new WorkItemImpl();
+		workItem.setParameter(ParserWorkItemHandler.INPUT, PERSON_JSON);
+		workItem.setParameter(ParserWorkItemHandler.FORMAT, ParserWorkItemHandler.JSON);
+		workItem.setParameter(ParserWorkItemHandler.TYPE,
+				"org.jbpm.process.workitem.parser.Person");
+		handler.executeWorkItem(workItem, new TestWorkItemManager(workItem));
+		Person result = (Person) workItem.getResult(ParserWorkItemHandler.RESULT);
+		assertEquals(AGE, result.getAge());
+		assertEquals(NAME, result.getName());
+	}
+
+	@Test
+	public void testObjectToJson() {
+		Person p = new Person(NAME, AGE);
+		WorkItemImpl workItem = new WorkItemImpl();
+		workItem.setParameter(ParserWorkItemHandler.INPUT, p);
+		workItem.setParameter(ParserWorkItemHandler.FORMAT, ParserWorkItemHandler.JSON);
+		handler.executeWorkItem(workItem, new TestWorkItemManager(workItem));
+		String result = (String) workItem.getResult(ParserWorkItemHandler.RESULT);
+		assertEquals(PERSON_JSON, result);
+	}
+
+	private class TestWorkItemManager implements WorkItemManager {
+
+		private WorkItem workItem;
+
+		TestWorkItemManager(WorkItem workItem) {
+			this.workItem = workItem;
+		}
+
+		public void completeWorkItem(long id, Map<String, Object> results) {
+			((WorkItemImpl) workItem).setResults(results);
+
+		}
+
+		public void abortWorkItem(long id) {
+
+		}
+
+		public void registerWorkItemHandler(String workItemName,
+				WorkItemHandler handler) {
+
+		}
+
+	}
+
+}

jbpm-workitems/src/test/java/org/jbpm/process/workitem/parser/Person.java

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+package org.jbpm.process.workitem.parser;
+
+import javax.xml.bind.annotation.XmlRootElement;
+
+@XmlRootElement
+public class Person {
+
+	private String name;
+	private int age;
+
+
+
+	public Person(String name, int age) {
+		super();
+		this.name = name;
+		this.age = age;
+	}
+
+	public Person() {
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public int getAge() {
+		return age;
+	}
+
+	public void setAge(int age) {
+		this.age = age;
+	}
+
+
+}