How can one get the name of the class from a static method in that class. For example
public class MyClass {
public static String getClassName() {
String name = ????; // what goes here so the string "MyClass" is returned
return name;
}
}
To put it in context, I actually want to return the class name as part of a message in an exception.
You could do something really sweet by using JNI like this:
MyObject.java:
public class MyObject
{
static
{
System.loadLibrary( "classname" );
}
public static native String getClassName();
public static void main( String[] args )
{
System.out.println( getClassName() );
}
}
then:
javac MyObject.java
javah -jni MyObject
then:
MyObject.c:
#include "MyObject.h"
JNIEXPORT jstring JNICALL Java_MyObject_getClassName( JNIEnv *env, jclass cls )
{
jclass javaLangClass = (*env)->FindClass( env, "java/lang/Class" );
jmethodID getName = (*env)->GetMethodID( env, javaLangClass, "getName",
"()Ljava/lang/String;" );
return (*env)->CallObjectMethod( env, cls, getName );
}
Then compile the C up into a shared library called libclassname.so and run the java!
*chuckle
Verbatim use of caller's class like MyClass.class.getName() actually does the job, but is prone to copy/paste errors if you propagate this code to numerous classes/subclasses where you need this class name.
And Tom Hawtin's recipe is in fact not bad, one just needs to cook it the right way :)
In case you have a base class with a static method that may be called from subclasses, and this static method needs to know the actual caller's class, this may be achieved like the following:
class BaseClass {
static sharedStaticMethod (String callerClassName, Object... otherArgs) {
useCallerClassNameAsYouWish (callerClassName);
// and direct use of 'new Object() { }.getClass().getEnclosingClass().getName()'
// instead of 'callerClassName' is not going to help here,
// as it returns "BaseClass"
}
}
class SubClass1 extends BaseClass {
static someSubclassStaticMethod () {
// this call of the shared method is prone to copy/paste errors
sharedStaticMethod (SubClass1.class.getName(),
other_arguments);
// and this call is safe to copy/paste
sharedStaticMethod (new Object() { }.getClass().getEnclosingClass().getName(),
other_arguments);
}
}