com.hp.util.test

Class UnitTestSupportProxy

java.lang.Object

com.hp.util.test.UnitTestSupportProxy

All Implemented Interfaces:

InvocationHandler

public class UnitTestSupportProxy
extends Object
implements InvocationHandler

This class can be used by subsystems that want to provide JUnit Support to unit tests that are defined in external packages (i.e. they require public access), and yet prevent the same access from production code.

For example, a class that wishes to allow its internal cache to be cleared by unit tests, but to disallow production code the same access, might implement something like this:

 public class MyClass {

    // singleton pattern with our instance stored in the field INSTANCE ...

    /** Return a support instance. Calling clear() will clear
     * the caches.
     */
    public static UnitTestSupport getUnitTestSupport() {
        return UnitTestSupportProxy.injectProxy(new MyUTS());
    }

    // this is our support implementation that clears our caches
    private static class MyUTS extends UnitTestSupportAdapter {

        // the proxy wrapper will ONLY allow this method to
        // run if it determines that the caller is a unit test
        // method annotated with a "Before/BeforeClass/After/AfterClass"
        @Override
        public void clear() {
            clearCache();
        }

        // clear the cache on our singleton instance
        private void clearCache() {
            synchronized (MyClass.INSTANCE.cache) {
                MyClass.INSTANCE.cache.clear();
            }
        }
    }
 }
 

When a method on the UnitTestSupport interface is invoked, the proxy examines the calling stack to verify that the caller is a method that has been annotated with any of the following JUnit annotations:

• org.junit.BeforeClass
• org.junit.AfterClass
• org.junit.Before
• org.junit.After

If this is the case, the method on the wrapped implementation is invoked. If this is not the case, a RuntimeException is thrown.

Author:

Simon Hunt

Method Summary

Modifier and Type	Method and Description
static UnitTestSupport	injectProxy(UnitTestSupport obj) This method returns a proxy wrapper for the given UnitTestSupport implementation.
Object	invoke(Object proxy, Method method, Object[] args)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

invoke

public Object invoke(Object proxy,
                     Method method,
                     Object[] args)
              throws Throwable

Specified by:

invoke in interface InvocationHandler

Throws:

Throwable

injectProxy

public static UnitTestSupport injectProxy(UnitTestSupport obj)

This method returns a proxy wrapper for the given UnitTestSupport implementation.

Parameters:

obj - the UnitTestSupport implementation

Returns:

the wrapped implementation