/*
* Copyright 2006-2007 the original author or authors.
*
* 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.springframework.batch.item.xml;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLEventWriter;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
/**
* This class provides a little bit of indirection to avoid ugly conditional object creation. It is unfortunately
* a bit redundant assuming a Spring 3.0 environment, but is necessary to work with Spring WS 1.5.x.
* <br>
* The returned object determines whether the environment has Spring OXM as included in the Spring 3.x series of relies
* or whether it has Spring OXM from Spring WS 1.5x and factories a StaxSource instance appropriately.
* <br>
* As the only class state maintained is to cache java reflection metadata, which is thread-safe, this class is thread-safe.
*
* @author Josh Long
*
*/
public abstract class StaxUtils {
private static final Log logger = LogFactory.getLog(StaxUtils.class);
private static ClassLoader defaultClassLoader = ClassUtils.getDefaultClassLoader();
// regular object.
private static String staxSourceClassNameOnSpringWs15 = "org.springframework.xml.transform.StaxSource";
private static String staxResultClassNameOnSpringOxm15 = "org.springframework.xml.transform.StaxResult";
// in Spring 3, StaxUtils is package private, so use static utility StaxUtils#createStaxSource / StaxUtils#createStaxResult
private static String staxSourceClassNameOnSpringOxm30 = "org.springframework.util.xml.StaxUtils";
private static boolean hasSpringWs15StaxSupport = ClassUtils.isPresent(staxSourceClassNameOnSpringWs15, defaultClassLoader);
private static boolean hasSpring30StaxSupport = ClassUtils.isPresent(staxSourceClassNameOnSpringOxm30, defaultClassLoader);
private static Method staxUtilsSourceMethodOnSpring30, staxUtilsResultMethodOnSpring30;
private static Constructor<?> staxSourceClassCtorOnSpringWs15, staxResultClassCtorOnSpringWs15;
static {
try {
// cache the factory method / constructor so that we spend as little time in reflection as possible
if (hasSpring30StaxSupport) {
Class<?> clzz = ClassUtils.forName(staxSourceClassNameOnSpringOxm30, defaultClassLoader);
// javax.xml.transform.Source
staxUtilsSourceMethodOnSpring30 = ClassUtils.getStaticMethod(clzz, "createStaxSource", XMLEventReader.class);
// javax.xml.transform.Result
staxUtilsResultMethodOnSpring30 = ClassUtils.getStaticMethod(clzz, "createStaxResult", XMLEventWriter.class);
} else if (hasSpringWs15StaxSupport) {
// javax.xml.transform.Source
Class<?> staxSourceClassOnSpringWs15 = ClassUtils.forName(staxSourceClassNameOnSpringWs15, defaultClassLoader);
staxSourceClassCtorOnSpringWs15 = staxSourceClassOnSpringWs15.getConstructor(XMLEventReader.class);
// javax.xml.transform.Result
Class<?> staxResultClassOnSpringWs15 = ClassUtils.forName(staxResultClassNameOnSpringOxm15, defaultClassLoader);
staxResultClassCtorOnSpringWs15 = staxResultClassOnSpringWs15.getConstructor(XMLEventWriter.class);
} else {
if (logger.isDebugEnabled()) {
logger.debug("'StaxSource' was not detected in Spring 3.0's OXM support or Spring WS 1.5's OXM support. " +
"This is a problem if you intend to use the " +StaxEventItemWriter.class.getName() + " or " +
StaxEventItemReader.class.getName()+". Please add the appropriate dependencies.");
}
}
} catch (Exception ex) {
logger.error("Could not precache required class and method metadata in " + StaxUtils.class.getName());
}
}
public static Source getSource(XMLEventReader r) throws Exception {
if (hasSpring30StaxSupport) {
// org.springframework.util.xml.StaxUtils.createStaxSource(r)
Object result = staxUtilsSourceMethodOnSpring30.invoke(null,r);
Assert.isInstanceOf(Source.class, result, "the result should be assignable to " + Source.class.getName());
return (Source) result;
} else if (hasSpringWs15StaxSupport) {
Object result = staxSourceClassCtorOnSpringWs15.newInstance(r);
Assert.isInstanceOf(Source.class, result, "the result should be assignable to " + Source.class.getName());
return (Source) result;
}
// maybe you don't have either environment?
return null;
}
public static Result getResult(XMLEventWriter w) throws Exception {
if (hasSpring30StaxSupport) {
Object result = staxUtilsResultMethodOnSpring30.invoke(null,w);
Assert.isInstanceOf(Result.class, result, "the result should be assignable to " + Result.class.getName());
return (Result) result;
} else if (hasSpringWs15StaxSupport) {
Object result = staxResultClassCtorOnSpringWs15.newInstance(w);
Assert.isInstanceOf(Result.class, result, "the result should be assignable to " + Result.class.getName());
return (Result) result;
}
// maybe you don't have either environment?
return null;
}
public static XMLEventWriter getXmlEventWriter(Result r) throws Exception {
Method m = r.getClass().getDeclaredMethod("getXMLEventWriter");
boolean accessible = m.isAccessible();
m.setAccessible(true);
Object result = m.invoke(r);
m.setAccessible(accessible);
return (XMLEventWriter) result;
}
public static XMLEventReader getXmlEventReader(Source s) throws Exception {
Method m = s.getClass().getDeclaredMethod("getXMLEventReader");
boolean accessible = m.isAccessible();
m.setAccessible(true);
Object result = m.invoke(s);
m.setAccessible(accessible);
return (XMLEventReader) result;
}
}