java code for Method Replacement

/*
Pro Spring
By Rob Harrop
Jan Machacek
ISBN: 1-59059-461-4
Publisher: Apress
*/



///////////////////////////////////////////////////////////////////////////////////////
//File: replacement.xml





String






///////////////////////////////////////////////////////////////////////////////////////

public class ReplacementTarget {

public String formatMessage(String msg) {
return "

" + msg + "

";
}

public String formatMessage(Object msg) {
return "

" + msg + "

";
}

public void foo() {

}
}

///////////////////////////////////////////////////////////////////////////////////////
import java.lang.reflect.Method;

import org.springframework.beans.factory.support.MethodReplacer;

public class FormatMessageReplacer implements MethodReplacer {

public Object reimplement(Object target, Method method, Object[] args)
throws Throwable {

if (isFormatMessageMethod(method)) {

String msg = (String) args[0];

return "

" + msg + "

";
} else {
throw new IllegalArgumentException("Unable to reimplement method "
+ method.getName());
}
}

private boolean isFormatMessageMethod(Method method) {

// check correct number of params
if (method.getParameterTypes().length != 1) {
return false;
}

// check method name
if (!("formatMessage".equals(method.getName()))) {
return false;
}

// check return type
if (method.getReturnType() != String.class) {
return false;
}

// check parameter type is correct
if (method.getParameterTypes()[0] != String.class) {
return false;
}

return true;
}

}


///////////////////////////////////////////////////////////////////////////////////////
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
import org.springframework.util.StopWatch;

public class MethodReplacementExample {

public static void main(String[] args) {
BeanFactory factory = new XmlBeanFactory(new FileSystemResource(
"build/replacement.xml"));

ReplacementTarget replacementTarget = (ReplacementTarget) factory
.getBean("replacementTarget");
ReplacementTarget standardTarget = (ReplacementTarget) factory
.getBean("standardTarget");

displayInfo(replacementTarget);
displayInfo(standardTarget);
}

private static void displayInfo(ReplacementTarget target) {
System.out.println(target.formatMessage("Hello World!"));

StopWatch stopWatch = new StopWatch();
stopWatch.start("perfTest");

for (int x = 0; x < 1000000; x++) {
String out = target.formatMessage("foo");
}

stopWatch.stop();

System.out.println("1000000 invocations took: "
+ stopWatch.getTotalTimeMillis() + " ms");
}
}