com.jamonapi.proxy.MonProxy Maven / Gradle / Ivy
package com.jamonapi.proxy;
import com.jamonapi.MonKeyImp;
import com.jamonapi.Monitor;
import com.jamonapi.MonitorFactory;
import com.jamonapi.utils.Logger;
import com.jamonapi.utils.Misc;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.SQLException;
import java.util.Date;
/**
* By using this proxy class ANY java interface can be monitored for performance and exceptions via JAMon.
* In particular the 'monitor' method is great for wrapping (and so monitoring) any of the JDBC classes which
* all implement interfaces (i.e. Connection, ResultSet, Statement, PreparedStatement,...). It tracks performance
* stats (hits/avg/min/max/...) for method calls and Exceptions.
*
* Sample code:
* {@code
* ResultSet rs= MonProxyFactory.monitor(resultSet);
* Connection conn=MonProxyFactory.monitor(connection);
* MyInterface my=(MyInterface) MonProxyFactory.monitor(myObject);//myObject implements MyInterface
* YourInterface your=(YourInterface) MonProxyFactory.monitor(yourObject);//myObject implements MyInterface
* }
*
* Subsequent public method calls on this interface will be monitored. Quite cool. If the proxy is disabled
* the Object will be returned unchanged.
*
* Note the object passed MUST implement an interface or a runtime exception will occur i..e it can't be a
* plain java object.
*
* Also, to change from the default labeler interface you must do the following on your monitored object.
* {@code
* Map map=(Map) MonProxyFactory.monitor(new HashMap());
* MonProxy monProxy=MonProxyFactory.getMonProxy((Proxy)map);
* monProxy.setLabeler(new MyWonderfulLabeler());
* }
*
*/
public class MonProxy implements InvocationHandler {
private Object monitoredObj;// underlying object
Params params;// parameters associated with monitoring
private MonProxyLabelerInt labelerInt;
private static Method EQUALS_METHOD;
static {
try {
EQUALS_METHOD = Object.class.getMethod("equals",
new Class[] { Object.class });
} catch (Exception e) {
Logger.log("Error trying to create reflective equals method. This error should never happen: "+e);
}
}
MonProxy(Object monitoredObj, Params params, MonProxyLabelerInt labelerInt) {
this.monitoredObj = monitoredObj;
this.params = params;
this.labelerInt=labelerInt;
this.labelerInt.init(this);
}
/** Return the underlying object being Monitored. If the monitored object is wrapped with another Monitored object
* it will call until MonProxy is not returned (i.e. find the underlying monitored object */
public Object getMonitoredObject() {
return getMonitoredObject(monitoredObj);
}
/** Static method that returns the underlying/wrapped/monitored object if the passed object is an interfaced monitored by JAMon else
* if not simply return the object unchanged. It will follow the chain of MonProxy objects until
* the first non-MonProxy object is returned. This could return another type of Proxy object too.
*/
public static Object getMonitoredObject(Object obj) {
if (obj == null)
return null;
// loop until the monitored object is not a MonProxy object.
// note this is a recursive call.
while (Proxy.isProxyClass(obj.getClass())
&& (Proxy.getInvocationHandler(obj) instanceof MonProxy)) {
MonProxy monProxy = (MonProxy) Proxy.getInvocationHandler(obj);
obj=monProxy.getMonitoredObject();
}
return obj;
}
/** Set labeler to be called when summary stats are recorded for a method call or when the interface throws an exception */
public void setLabeler(MonProxyLabelerInt labelerInt) {
this.labelerInt=labelerInt;
}
/** Get current labeler */
public MonProxyLabelerInt getLabeler() {
return labelerInt;
}
/** Method that monitors method invocations of the proxied interface. This method is not explicitly called.
* The MonProxy class automatically calls it.
*/
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
Monitor mon = null;
boolean isExceptionSummaryEnabled = (params.isExceptionSummaryEnabled && params.isEnabled);// track jamon stats for Exceptions?
boolean isExceptionDetailEnabled = (params.isExceptionDetailEnabled && params.isEnabled);// save detailed stack trace in the exception buffer?
// Because this monitor string is created every time I use a StringBuffer as it may be more effecient.
// I didn't do this in the exception part of the code as they shouldn't be called as often.
if (params.isInterfaceEnabled && params.isEnabled) {
mon = MonitorFactory.start(labelerInt.getSummaryLabel(method));
}
try {
// Special logic must be performed for 'equals'. If not nonproxy.equals(proxy)
// will not return true
if (method.equals(EQUALS_METHOD))
return Boolean.valueOf(equals(args[0]));
else
return method.invoke(monitoredObj, args);// executes underlying interfaces method;
} catch (InvocationTargetException e) {
if (isExceptionSummaryEnabled || isExceptionDetailEnabled) {
String sqlMessage = "";
String detailStackTrace=null;
Throwable rootCause = e.getCause();
// Add special info if it is a SQLException
if (rootCause instanceof SQLException
&& isExceptionSummaryEnabled) {
SQLException sqlException = (SQLException) rootCause;
sqlMessage = ",ErrorCode=" + sqlException.getErrorCode()
+ ",SQLState=" + sqlException.getSQLState();
}
if (isExceptionSummaryEnabled) {
// Add jamon entries for Exceptions
detailStackTrace=Misc.getExceptionTrace(rootCause);
MonitorFactory.add(new MonKeyImp(
MonitorFactory.EXCEPTIONS_LABEL,
detailStackTrace,
"Exception"), 1); // counts total exceptions from jamon
MonitorFactory.add(new MonKeyImp(
"MonProxy-Exception: InvocationTargetException",
detailStackTrace,
"Exception"), 1); //counts total exceptions for MonProxy
MonitorFactory.add(new MonKeyImp(
"MonProxy-Exception: Root cause exception="
+ rootCause.getClass().getName()
+ sqlMessage,
detailStackTrace,
"Exception"), 1); // Message for the exception
MonitorFactory.add(new MonKeyImp(
labelerInt.getExceptionLabel(method),
detailStackTrace,
"Exception"),
1); // Exception and method that threw it.
}
// Add stack trace to buffer if it is enabled.
if (isExceptionDetailEnabled) {
if (detailStackTrace==null)
detailStackTrace=Misc.getExceptionTrace(rootCause);
params.exceptionBuffer.addRow(new Object[] {
new Long(++params.exceptionID), new Date(),
detailStackTrace, method.toString(), });
}
} // end if (enabled)
throw e.getCause();
} finally {
if (mon != null)
mon.stop();
}
}
/** When this is called on the proxy object it is the same as calling
* proxyObject1.equals(proxyObject2) is the same as calling originalObject1.equals(originalObject2)
*
*/
@Override
public boolean equals(Object obj) {
return getMonitoredObject().equals(getMonitoredObject(obj));
}
}