When developing an application -
even more when you just develop some parts of it- for me when having other people testing, it's always interesting - what information they fill into the objects they pass along to the methods ..
This becomes even more relevant - if the applications that are using your methods (webservices ...), are tested and developed by a 3rd party.
So during one of my flights a built up a quick example .. for an object-logger, with using java.lang.reflect. package - as I got really fascinated by this runtime-API :) and JDK1.3 doesn't support the XMLEncode ( decode package, that came along with 1.4 ..
The following code is just intended - as an example, of the usage of reflection, but why not using some funnny techs/api*s for such things too?!
package log;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
import java.util.logging.*;
/**
* Fast and simple ObjectLogger that prints out the values of
*
public fields and executes all <b>public</b>
* getXXX methods.
* This is done by usage of java.lang.reflection API
* @author Clemens Utschig - Utschig
* @version 1.0
* @date 23.03.2004
*/
public class ObjectLogger {
/**
* The apache Logger
*/
private static Logger mLogger;
/**
* GoF Singleton Instance, excutes one time the
*
private constructor
*
private static ObjectLogger mObjectLogger = new ObjectLogger();
/**
* GoF Singleton - therfor private Constructor - excuted only once,
* just initalized the logger
*/
private ObjectLogger() {
mLogger = Logger.getLogger("ObjectLogger");
}
/**
* Returns the singleton - instance, created as by the
* member var.
* @return the instance of the ObjectLogger
*/
public static ObjectLogger getInstance () {
return mObjectLogger;
}
/**
* Logs the
public fields of a given
* Object !
* @param pObject the Object to log
*/
public static void logObject (Object pObject) {
if (pObject != null) {
mLogger.info(" --------- start logging Object ----------");
mLogger.info("ClassName: " + pObject.getClass().getName());
// get the publid fields with reflection
Field [] objectFields = pObject.getClass().getFields();
if ((objectFields != null) && (objectFields.length > 0)) {
mLogger.info(" --------- public members ----------");
for (int fieldIndex = 0; fieldIndex < objectFields.length; fieldIndex++) {
try {
mLogger.info(" - Name [" +objectFields[fieldIndex].getName()+ "] " +
" type [" +objectFields[fieldIndex].getType()+ "] " +
" value [" +objectFields[fieldIndex].get(pObject)+ "] ");
} catch (IllegalAccessException illegalAccessExc) {
mLogger.info("IllegalArgumentException");
}
}
}
// get the pulic methods
Method [] objectMethods = pObject.getClass().getMethods();
if ((objectMethods != null) && (objectMethods.length > 0)) {
mLogger.info(" --------- Invocation of methods ----------");
for (int objectMethodIndex = 0; objectMethodIndex < objectMethods.length; objectMethodIndex++) {
try {
if ((objectMethods[objectMethodIndex].getParameterTypes().length == 0) &&
(objectMethods[objectMethodIndex].getName().startsWith("get"))){
mLogger.info(" - MethodName [" + objectMethods[objectMethodIndex].getName()+ "] " +
" type [" + objectMethods[objectMethodIndex].getReturnType().getName() + "]" +
" value [" + objectMethods[objectMethodIndex].invoke(pObject, new Object [] {}) + "] ");
}
} catch (InvocationTargetException invocationTargetExc) {
// do nothing
} catch (IllegalAccessException illegalAccessExc) {
// do nothing
} catch (Exception allOthers) {
// do nothing too
}
}
}
mLogger.info(" --------- End logging Object ----------");
} else {
mLogger.warning("Object given is NULL !");
}
}
/**
* Logs the
public fields/methods of a given Object Array !
* @param pObject[] the ObjectArray to log
*/
public static void logObject (Object pObject []) {
if (pObject != null) {
mLogger.info(" -- start logging ObjectArray, size: " + pObject.length + " --");
for (int objectIndex = 0; objectIndex < pObject.length; objectIndex++) {
logObject(pObject[objectIndex]);
}
mLogger.info(" -- end logging ObjectArray --" );
} else {
mLogger.warning("ObjectArray given is null !");
}
}
