/*
    * Copyright 2011 The Kuali Foundation
    *
    * Licensed under the Educational Community License, Version 1.0 (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.opensource.org/licenses/ecl1.php
    *
   * 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.kuali.rice.core.test;
  
  import static org.junit.Assert.assertEquals;
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.io.StringReader;
  import java.io.StringWriter;
  
  import javax.xml.bind.JAXBContext;
  import javax.xml.bind.Marshaller;
  import javax.xml.bind.Unmarshaller;
  
  /**
   * A class with some assertion utilities for JAXB-related operations. 
   * 
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public final class JAXBAssert {
  	
  	private JAXBAssert() {}
  	
  	/**
  	 * Performs the following steps and assertions:
  	 * 
  	 * <ol>
  	 *   <li>Creates a new JAXBContext with the given list of classesToBeBound.</li>
  	 *   <li>Marshals the provided objectToMarshall to XML.</li>
  	 *   <li>Unmarshals the marshaled XML to recreate the original object.<li>
  	 *   <li>Asserts that the newly unmarhsaled object and the original provided object are equal by invoking {@link Object#equals(Object)}.</li>
  	 *   <li>Unmarshals the given expectedXml to an object and asserts that it is equal with the original unmarshaled object by invoking {@link Object#equals(Object)}.</li>
  	 * </ol>  
  	 *  
  	 * @param objectToMarshal the object to marshal to XML using JAXB
  	 * @param expectedXml an XML string that will be unmarshaled to an Object and compared with objectToMarshal using {@link Object#equals(Object)}
  	 * @param classesToBeBound - list of java classes to be recognized by the created JAXBContext
  	 * 
  	 */
  	public static void assertEqualXmlMarshalUnmarshal(Object objectToMarshal, String expectedXml, Class<?> ... classesToBeBound) {
  		String marshaledXml = null;
  		try {
  		  JAXBContext jaxbContext = JAXBContext.newInstance(classesToBeBound);
  		  Marshaller marshaller = jaxbContext.createMarshaller();
  		  
  		  StringWriter stringWriter = new StringWriter();
  		  
  		  marshaller.marshal(objectToMarshal, stringWriter);
  
  		  marshaledXml = stringWriter.toString();
  		  
  		  Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
  		  
  		  Object actual = unmarshaller.unmarshal(new StringReader(stringWriter.toString()));
  		  assertEquals("Unmarshalled object should be equal to original objectToMarshall.", objectToMarshal, actual);
  		  
  		  Object expected = unmarshaller.unmarshal(new StringReader(expectedXml.trim()));
  		  assertEquals("Unmarshalled objects should be equal.", expected, actual);
  		} catch (Throwable e) {
  			System.err.println("Outputting marshaled XML from failed assertion:\n" + marshaledXml);
  			if (e instanceof RuntimeException) {
  				throw (RuntimeException)e;
  			} else if (e instanceof Error) {
  				throw (Error)e;
  			}
  			throw new RuntimeException("Failed to marshall/unmarshall with JAXB.  See the nested exception for details.", e);
  		}
  	}
  	
  	public static void assertEqualXmlMarshalUnmarshalWithResource(Object objectToMarshal, InputStream expectedXml, Class<?> ... classesToBeBound) throws IOException {
  		BufferedReader reader = new BufferedReader(new InputStreamReader(expectedXml));
  		StringWriter writer = new StringWriter();
  		int data = -1;
  		while ((data = reader.read()) != -1) {
  			writer.write(data);
  		}
  		assertEqualXmlMarshalUnmarshal(objectToMarshal, writer.toString(), classesToBeBound);
  	}
  	
  
  }