--- /dev/null
+/*
+ * Copyright 2005-2010 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.wamblee.general;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+
+import javax.naming.InitialContext;
+import javax.naming.NamingException;
+
+/**
+ * Proxy factory that can provide contextual references to objects retrieved
+ * through a lookup mechanism.
+ *
+ * @param T
+ * Interface to proxy.
+ * @author Erik Brakkee
+ *
+ */
+public class LookupProxyFactory<T> {
+
+ /**
+ * Interface to lookup the object to delegate to.
+ *
+ * @author Erik Brakkee
+ */
+ public static interface Lookup {
+ /**
+ * Looks up the object.
+ * @return Object (non-null)
+ * @throws Any exception in case the object cannot be found.
+ */
+ Object lookup() throws Exception;
+ }
+
+ /**
+ * Exception thrown in case an object cannot be retrieved from JNDI.
+ *
+ * @author Erik Brakkee
+ */
+ public static class LookupException extends RuntimeException {
+ public LookupException(String aMsg, Throwable aCause) {
+ super(aMsg, aCause);
+ }
+
+ public LookupException(String aMsg) {
+ super(aMsg);
+ }
+ }
+
+ /**
+ * Invocation handler that does a lookup in JNDI and invokes the method on the
+ * object it found.
+ *
+ * @author Erik Brakkee
+ */
+ private class LookupInvocationHandler implements InvocationHandler {
+
+ @Override
+ /**
+ * @throws JndiWiringException in case the object could not be retrieved from JNDI.
+ */
+ public Object invoke(Object aProxy, Method aMethod, Object[] aArgs)
+ throws Throwable {
+ Object svcObj = null;
+ try {
+ svcObj = lookup.lookup();
+ } catch (Exception e) {
+ throw new LookupException(
+ "Error looking up object", e);
+ }
+ if (svcObj == null) {
+ throw new LookupException("Object at is null");
+ }
+ if (!clazz.isInstance(svcObj)) {
+ throw new LookupException("Object '" + svcObj + "' is not of type " + clazz.getName() +
+ " but of type " + svcObj.getClass().getName());
+ }
+ T svc = (T) svcObj;
+ try {
+ return aMethod.invoke(svc, aArgs);
+ } catch (InvocationTargetException e) {
+ throw e.getCause();
+ }
+ }
+ }
+
+ private Lookup lookup;
+ private Class clazz;
+
+ /**
+ * Constructs the factory.
+ *
+ * @param aClass
+ * Interface class of the service to proxy.
+ * @param aJndi JNDI name of the object to lookup.
+ *
+ */
+ public LookupProxyFactory(Class<T> aClass, Lookup aLookup) {
+ if (!aClass.isInterface()) {
+ throw new IllegalArgumentException("Class " + aClass.getName() +
+ " is not an interface");
+ }
+ clazz = aClass;
+ lookup = aLookup;
+ }
+
+ /**
+ * Gets the proxy that delegates to the thread-specific instance set by
+ * {@link #set(Object)}
+ *
+ * When at runtime the proxy cannot find lookup the object in JNDI, it
+ * throws {@link LookupException}.
+ *
+ * @return Proxy.
+ */
+ public T getProxy() {
+ InvocationHandler handler = new LookupInvocationHandler();
+ Class proxyClass = Proxy.getProxyClass(clazz.getClassLoader(),
+ new Class[] { clazz });
+ T proxy;
+ try {
+ proxy = (T) proxyClass.getConstructor(
+ new Class[] { InvocationHandler.class }).newInstance(
+ new Object[] { handler });
+ return proxy;
+ } catch (Exception e) {
+ throw new RuntimeException("Could not create proxy for " +
+ clazz.getName(), e);
+ }
+ }
+}
--- /dev/null
+/*
+ * Copyright 2005-2010 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.wamblee.general;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+import javax.naming.InitialContext;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.wamblee.general.LookupProxyFactory;
+import org.wamblee.general.LookupProxyFactory.Lookup;
+import org.wamblee.general.LookupProxyFactory.LookupException;
+
+public class LookupProxyFactoryTest {
+
+ private static final String NAA_NA_NA_NAA_NA = "naa, na, na, naa, na";
+
+ private static interface MyInterface {
+ int execute();
+ }
+
+ private MyInterface intf;
+ private Lookup lookup;
+ private MyInterface proxy;
+
+ @Before
+ public void setUp() throws Exception {
+ intf = mock(MyInterface.class);
+ lookup = mock(Lookup.class);
+
+ LookupProxyFactory<MyInterface> factory = new LookupProxyFactory<MyInterface>(
+ MyInterface.class, lookup);
+ proxy = factory.getProxy();
+ }
+
+ @After
+ public void tearDown() throws Exception {
+ // Empty.
+ }
+
+ @Test
+ public void testFound() throws Exception {
+ when(intf.execute()).thenReturn(1);
+ when(lookup.lookup()).thenReturn(intf);
+
+ assertEquals(1, proxy.execute());
+
+ }
+
+ @Test(expected = LookupException.class)
+ public void testNotFoundAtJndi() throws Exception {
+ when(lookup.lookup()).thenThrow(new RuntimeException("Object not found"));
+ proxy.execute();
+ }
+
+ @Test(expected = LookupException.class)
+ public void testWrongTypeAtJndi() throws Exception {
+ when(lookup.lookup()).thenReturn("my string");
+ when(intf.execute()).thenReturn(1);
+ proxy.execute();
+ }
+
+ @Test(expected = LookupException.class)
+ public void testNullAtJndi() throws Exception {
+ when(lookup.lookup()).thenReturn(null);
+ when(intf.execute()).thenReturn(1);
+ proxy.execute();
+ }
+
+ @Test
+ public void testFoundButInvocationThrowsException() throws Exception {
+ when(intf.execute()).thenThrow(new RuntimeException(NAA_NA_NA_NAA_NA));
+ when(lookup.lookup()).thenReturn(intf);
+ try {
+ proxy.execute();
+ } catch (RuntimeException e) {
+ assertEquals(NAA_NA_NA_NAA_NA, e.getMessage());
+ }
+ }
+
+}
git://wamblee.org / utils / commitdiff