From f11b6f604f6beffc085d9c077144bc89b6c7660f Mon Sep 17 00:00:00 2001
From: brinn <brinn>
Date: Mon, 9 Jun 2008 06:26:19 +0000
Subject: [PATCH] add: new class MonitoringProxy and unit tests
SVN: 6500
---
.../common/concurrent/MonitoringProxy.java | 333 ++++++++++++++++++
.../concurrent/MonitoringProxyTest.java | 312 ++++++++++++++++
2 files changed, 645 insertions(+)
create mode 100644 common/source/java/ch/systemsx/cisd/common/concurrent/MonitoringProxy.java
create mode 100644 common/sourceTest/java/ch/systemsx/cisd/common/concurrent/MonitoringProxyTest.java
diff --git a/common/source/java/ch/systemsx/cisd/common/concurrent/MonitoringProxy.java b/common/source/java/ch/systemsx/cisd/common/concurrent/MonitoringProxy.java
new file mode 100644
index 00000000000..1492fbbfd74
--- /dev/null
+++ b/common/source/java/ch/systemsx/cisd/common/concurrent/MonitoringProxy.java
@@ -0,0 +1,333 @@
+/*
+ * Copyright 2008 ETH Zuerich, CISD
+ *
+ * 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 ch.systemsx.cisd.common.concurrent;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Future;
+
+import ch.systemsx.cisd.common.exceptions.StopException;
+import ch.systemsx.cisd.common.exceptions.TimeoutException;
+
+/**
+ * A class that can provide a dynamic {@link Proxy} for an interface that delegates the method
+ * invocations to an implementation of this interface, monitoring for calls to
+ * {@link Thread#interrupt()} and for timeouts. (Note that by default no timeout is set.)
+ * <p>
+ * On calls to {@link Thread#interrupt()} the proxy will throw a {@link StopException}, on timeouts
+ * a {@link TimeoutException}.
+ * <p>
+ * The proxy can be configured by chaining. If all options have been set, the actual proxy can be
+ * obtained by calling {@link #get()}. In order to e.g. set the timeout to 10s, the following call
+ * chain can be used:
+ *
+ * <pre>
+ * If proxy = MonitoringProxy.create(If.class, someInstance).timeoutMillis(10000L).get();
+ * </pre>
+ *
+ * Instead of throwing a exception, the proxy can also be configured to provide special error values
+ * on error conditions. This configuration is done by {@link #errorValueOnInterrupt()} for thread
+ * interrupts and {@link #errorValueOnTimeout()} for timeouts.
+ * <p>
+ * The error return values can be set, either for the type of the return value of a method, or by
+ * the method itself. If present, the specific method-value mapping will take precedence of the
+ * generic return-type-value mapping. In order to set a value "ERROR" for String return types, use a
+ * chaining call like:
+ *
+ * <pre>
+ * If proxy =
+ * MonitoringProxy.create(If.class, someInstance).errorValueOnInterrupt()
+ * .errorTypeValueMapping(String.class, "ERROR").get();
+ * </pre>
+ *
+ * @author Bernd Rinn
+ */
+public class MonitoringProxy<T>
+{
+
+ private final static ExecutorService executor =
+ new NamingThreadPoolExecutor("Monitoring Proxy").daemonize();
+
+ private final DelegatingInvocationHandler<T> delegate;
+
+ private final Map<Class, Object> errorTypeValueMap;
+
+ private final Map<Method, Object> errorMethodValueMap;
+
+ private final MonitoringInvocationHandler handler;
+
+ private final T proxy;
+
+ private long timeoutMillis;
+
+ private boolean errorValueOnTimeout;
+
+ private boolean errorValueOnInterrupt;
+
+ private String nameOrNull;
+
+ private static class DelegatingInvocationHandler<T> implements InvocationHandler
+ {
+
+ private final T objectToProxyFor;
+
+ private DelegatingInvocationHandler(T objectToProxyFor)
+ {
+ this.objectToProxyFor = objectToProxyFor;
+ }
+
+ public Object invoke(Object proxy, Method method, Object[] args) throws Throwable
+ {
+ try
+ {
+ return method.invoke(objectToProxyFor, args);
+ } catch (InvocationTargetException ex)
+ {
+ throw ex.getTargetException();
+ }
+ }
+
+ }
+
+ private static String describe(Method method)
+ {
+ final StringBuilder builder = new StringBuilder(100);
+ builder.append("Call to method '");
+ builder.append(method.getDeclaringClass().getSimpleName());
+ builder.append('.');
+ builder.append(method.getName());
+ builder.append('(');
+ boolean addComma = false;
+ for (Class<?> clazz : method.getParameterTypes())
+ {
+ if (addComma)
+ {
+ builder.append(',');
+ }
+ builder.append(clazz.getSimpleName());
+ addComma = true;
+ }
+ builder.append(")'");
+ return builder.toString();
+ }
+
+ private static Map<Class, Object> createDefaultErrorTypeValueMap()
+ {
+ final Map<Class, Object> result = new HashMap<Class, Object>();
+ result.put(Void.TYPE, Void.TYPE.cast(null));
+ result.put(Boolean.TYPE, false);
+ result.put(Byte.TYPE, (byte) 0);
+ result.put(Short.TYPE, (short) 0);
+ result.put(Integer.TYPE, 0);
+ result.put(Long.TYPE, 0L);
+ return result;
+ }
+
+ @SuppressWarnings("unchecked")
+ private static <T> T cast(Class<T> interfaceClass, Object objectToProxyFor)
+ {
+ return (T) objectToProxyFor;
+ }
+
+ private class MonitoringInvocationHandler implements InvocationHandler
+ {
+
+ public Object invoke(final Object myProxy, final Method method, final Object[] args)
+ throws Throwable
+ {
+ final Future<Object> future = executor.submit(new NamedCallable<Object>()
+ {
+ public Object call() throws Exception
+ {
+ try
+ {
+ return delegate.invoke(myProxy, method, args);
+ } catch (Throwable th)
+ {
+ if (th instanceof Error)
+ {
+ throw (Error) th;
+ } else
+ {
+ throw (Exception) th;
+ }
+ }
+ }
+
+ public String getCallableName()
+ {
+ if (nameOrNull != null)
+ {
+ return nameOrNull;
+ } else
+ {
+ return describe(method);
+ }
+ }
+ });
+ final ExecutionResult<Object> result =
+ ConcurrencyUtilities.getResult(future, timeoutMillis);
+ if (result.getStatus() == ExecutionStatus.TIMED_OUT)
+ {
+ if (errorValueOnTimeout == false)
+ {
+ throw new TimeoutException(describe(method) + " timed out (timeout="
+ + timeoutMillis + "ms).");
+ }
+ return getErrorValue(method);
+ }
+ if (result.getStatus() == ExecutionStatus.INTERRUPTED && errorValueOnInterrupt)
+ {
+ return getErrorValue(method);
+ }
+ return ConcurrencyUtilities.tryDealWithResult(result);
+ }
+
+ private Object getErrorValue(final Method method)
+ {
+ if (errorMethodValueMap.containsKey(method))
+ {
+ return errorMethodValueMap.get(method);
+ }
+ if (errorTypeValueMap.containsKey(method.getReturnType()))
+ {
+ return errorTypeValueMap.get(method.getReturnType());
+ }
+ return null;
+ }
+ }
+
+ private MonitoringProxy(Class<T> interfaceClass, T objectToProxyFor)
+ {
+ assert interfaceClass.isInterface();
+
+ this.errorTypeValueMap = createDefaultErrorTypeValueMap();
+ this.errorMethodValueMap = new HashMap<Method, Object>();
+ this.timeoutMillis = ConcurrencyUtilities.NO_TIMEOUT;
+ this.delegate = new DelegatingInvocationHandler<T>(objectToProxyFor);
+ this.handler = new MonitoringInvocationHandler();
+ this.proxy = createProxy(interfaceClass, objectToProxyFor);
+ }
+
+ private T createProxy(Class<T> interfaceClass, T objectToProxyFor)
+ {
+ final Class<?>[] interfaceClasses = new Class<?>[]
+ { interfaceClass };
+ final Object proxyInstance =
+ Proxy.newProxyInstance(interfaceClass.getClassLoader(), interfaceClasses, handler);
+ return cast(interfaceClass, proxyInstance);
+
+ }
+
+ /**
+ * Creates a {@link MonitoringProxy} of type <var>interfaceClass</var> for the
+ * <var>objectToProxyFor</var>.
+ *
+ * @param interfaceClass The type of the interface to proxy for. It is a programming error to
+ * provide a class that does not represent an interface.
+ * @param objectToProxyFor The object to proxy for.
+ * @return A monitoring proxy that can be configured as required and that finally provides the
+ * actual proxy with {@link #get()}.
+ */
+ public static <T> MonitoringProxy<T> create(Class<T> interfaceClass, T objectToProxyFor)
+ {
+ return new MonitoringProxy<T>(interfaceClass, objectToProxyFor);
+ }
+
+ /**
+ * Sets the timeout to <var>newTimeoutMillis</var>.
+ *
+ * @return This object (for chaining).
+ */
+ public MonitoringProxy<T> timeoutMillis(long newTimeoutMillis)
+ {
+ this.timeoutMillis = newTimeoutMillis;
+ return this;
+ }
+
+ /**
+ * Sets the mode where a special error value is provided on timeout.
+ *
+ * @return This object (for chaining).
+ */
+ public MonitoringProxy<T> errorValueOnTimeout()
+ {
+ this.errorValueOnTimeout = true;
+ return this;
+ }
+
+ /**
+ * Sets the mode where a special error value is provided on thread interruption.
+ *
+ * @return This object (for chaining).
+ */
+ public MonitoringProxy<T> errorValueOnInterrupt()
+ {
+ this.errorValueOnInterrupt = true;
+ return this;
+ }
+
+ /**
+ * Sets the name of this proxy (for setting the thread name) to <var>newName</var>.
+ *
+ * @return This object (for chaining).
+ */
+ public MonitoringProxy<T> name(String newName)
+ {
+ this.nameOrNull = newName;
+ return this;
+ }
+
+ /**
+ * Sets an error return <var>value</var> for the type <var>clazz</var>.
+ * <p>
+ * <i>A value set by this method is only relevant if the proxy is configured to return error
+ * values rather than to throw exceptions.</i>
+ */
+ public <V> MonitoringProxy<T> errorTypeValueMapping(Class<V> clazz, V value)
+ {
+ errorTypeValueMap.put(clazz, value);
+ return this;
+ }
+
+ /**
+ * Sets an error return <var>value</var> for the given <var>method</var>. This <var>value</var>
+ * takes precedence over the error type mapping for methods with the same return type.
+ * <p>
+ * <i>A value set by this method is only relevant if the proxy is configured to return error
+ * values rather than to throw exceptions.</i>
+ */
+ public MonitoringProxy<T> errorMethodValueMapping(Method method, Object value)
+ {
+ errorMethodValueMap.put(method, value);
+ return this;
+ }
+
+ /**
+ * Returns the actual proxy.
+ */
+ public T get()
+ {
+ return proxy;
+ }
+
+}
diff --git a/common/sourceTest/java/ch/systemsx/cisd/common/concurrent/MonitoringProxyTest.java b/common/sourceTest/java/ch/systemsx/cisd/common/concurrent/MonitoringProxyTest.java
new file mode 100644
index 00000000000..b73544be74e
--- /dev/null
+++ b/common/sourceTest/java/ch/systemsx/cisd/common/concurrent/MonitoringProxyTest.java
@@ -0,0 +1,312 @@
+/*
+ * Copyright 2008 ETH Zuerich, CISD
+ *
+ * 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 ch.systemsx.cisd.common.concurrent;
+
+import static org.testng.AssertJUnit.*;
+
+import java.util.Timer;
+import java.util.TimerTask;
+import java.util.regex.Pattern;
+
+import org.testng.annotations.BeforeTest;
+import org.testng.annotations.Test;
+
+import ch.systemsx.cisd.common.exceptions.StopException;
+import ch.systemsx.cisd.common.exceptions.TimeoutException;
+
+/**
+ * Test cases for the {@link MonitoringProxy}.
+ *
+ * @author Bernd Rinn
+ */
+public class MonitoringProxyTest
+{
+
+ private static final String THREAD_NAME = "Some Flaky Stuff";
+
+ private static final String THE_STRING = "some string";
+
+ private static final boolean THE_BOOLEAN = true;
+
+ private static final int THE_INTEGER = 17;
+
+ private static final Status THE_STATUS = Status.TWO;
+
+ private static final long TIMEOUT_MILLIS = 50L;
+
+ private ITest defaultReturningProxy;
+
+ private ITest exceptionThrowingProxy;
+
+ private static class SignalException extends RuntimeException
+ {
+ private static final long serialVersionUID = 1L;
+ }
+
+ enum Status
+ {
+ ONE, TWO, THREE, UUUPS, SPECIAL_UUUPS
+ }
+
+ interface ITest
+ {
+ void idle(boolean hang);
+
+ String getString(boolean hang);
+
+ boolean getBoolean(boolean hang);
+
+ int getInteger(boolean hang);
+
+ Status getStatus(boolean hang);
+
+ Status getSpecialStatus(boolean hang);
+
+ void throwSignalException() throws SignalException;
+ }
+
+ private static class TestImpl implements ITest
+ {
+ private final static Pattern THREAD_NAME_PATTERN =
+ Pattern.compile("Monitoring Proxy-T[0-9]+::" + THREAD_NAME);
+
+ private void hang(boolean hang)
+ {
+ if (hang)
+ {
+ while (true)
+ {
+ }
+ }
+ }
+
+ private void checkThreadName()
+ {
+ final String name = Thread.currentThread().getName();
+ assertTrue(name, THREAD_NAME_PATTERN.matcher(name).matches());
+ }
+
+ public void idle(boolean hang)
+ {
+ checkThreadName();
+ hang(hang);
+ }
+
+ public boolean getBoolean(boolean hang)
+ {
+ checkThreadName();
+ hang(hang);
+ return THE_BOOLEAN;
+ }
+
+ public int getInteger(boolean hang)
+ {
+ checkThreadName();
+ hang(hang);
+ return THE_INTEGER;
+ }
+
+ public String getString(boolean hang)
+ {
+ checkThreadName();
+ hang(hang);
+ return THE_STRING;
+ }
+
+ public Status getStatus(boolean hang)
+ {
+ checkThreadName();
+ hang(hang);
+ return THE_STATUS;
+ }
+
+ public Status getSpecialStatus(boolean hang)
+ {
+ checkThreadName();
+ hang(hang);
+ return THE_STATUS;
+ }
+
+ public void throwSignalException() throws SignalException
+ {
+ checkThreadName();
+ throw new SignalException();
+ }
+ }
+
+ @BeforeTest
+ public void testCreateMonitoringProxy() throws NoSuchMethodException
+ {
+ defaultReturningProxy =
+ MonitoringProxy.create(ITest.class, new TestImpl()).timeoutMillis(TIMEOUT_MILLIS)
+ .errorValueOnTimeout().name(THREAD_NAME).errorTypeValueMapping(
+ Status.class, Status.UUUPS).errorMethodValueMapping(
+ ITest.class.getMethod("getSpecialStatus", new Class<?>[]
+ { Boolean.TYPE }), Status.SPECIAL_UUUPS).get();
+ exceptionThrowingProxy =
+ MonitoringProxy.create(ITest.class, new TestImpl()).timeoutMillis(TIMEOUT_MILLIS)
+ .name(THREAD_NAME).get();
+ }
+
+ @Test
+ public void testVoid()
+ {
+ defaultReturningProxy.idle(false);
+ }
+
+ @Test
+ public void testVoidTimeoutNoException()
+ {
+ defaultReturningProxy.idle(true);
+ }
+
+ @Test(expectedExceptions = SignalException.class)
+ public void testThrowExceptionNullReturningPolicy()
+ {
+ defaultReturningProxy.throwSignalException();
+ }
+
+ @Test(expectedExceptions = SignalException.class)
+ public void testThrowExceptionExceptionThrowsPolicy()
+ {
+ exceptionThrowingProxy.throwSignalException();
+ }
+
+ @Test(expectedExceptions = TimeoutException.class)
+ public void testVoidTimeoutWithException()
+ {
+ exceptionThrowingProxy.idle(true);
+ }
+
+ @Test
+ public void testGetStringNullReturningPolicy()
+ {
+ assertEquals(THE_STRING, defaultReturningProxy.getString(false));
+ }
+
+ @Test
+ public void testGetStringExceptionThrowingPolicy()
+ {
+ assertEquals(THE_STRING, exceptionThrowingProxy.getString(false));
+ }
+
+ @Test
+ public void testGetStringTimeoutNoException()
+ {
+ assertNull(defaultReturningProxy.getString(true));
+ }
+
+ @Test(expectedExceptions = TimeoutException.class)
+ public void testGetStringTimeoutWithException()
+ {
+ exceptionThrowingProxy.getString(true);
+ }
+
+ @Test
+ public void testGetIntNullReturningPolicy()
+ {
+ assertEquals(THE_INTEGER, defaultReturningProxy.getInteger(false));
+ }
+
+ @Test
+ public void testGetIntExceptionThrowingPolicy()
+ {
+ assertEquals(THE_INTEGER, exceptionThrowingProxy.getInteger(false));
+ }
+
+ @Test
+ public void testGetBoolTimeoutReturnsDefault()
+ {
+ assertEquals(false, defaultReturningProxy.getBoolean(true));
+ }
+
+ @Test
+ public void testGetStatus()
+ {
+ assertEquals(THE_STATUS, defaultReturningProxy.getStatus(false));
+ }
+
+ @Test
+ public void testGetStatusTimeoutReturnsDefault()
+ {
+ assertEquals(Status.UUUPS, defaultReturningProxy.getStatus(true));
+ }
+
+ @Test
+ public void testGetSpecialStatusTimeoutReturnsMethodDefault()
+ {
+ assertEquals(Status.SPECIAL_UUUPS, defaultReturningProxy.getSpecialStatus(true));
+ }
+
+ @Test
+ public void testGetIntTimeoutReturnsDefault()
+ {
+ assertEquals(0, defaultReturningProxy.getInteger(true));
+ }
+
+ @Test(expectedExceptions = TimeoutException.class)
+ public void testGetIntTimeoutWithException()
+ {
+ exceptionThrowingProxy.getInteger(true);
+ }
+
+ @Test(expectedExceptions = StopException.class)
+ public void testInterruptTheUninterruptableThrowsException()
+ {
+ final ITest proxy =
+ MonitoringProxy.create(ITest.class, new TestImpl()).timeoutMillis(1000L).name(
+ THREAD_NAME).get();
+ final Thread currentThread = Thread.currentThread();
+ final Timer timer = new Timer();
+ timer.schedule(new TimerTask()
+ {
+ @Override
+ public void run()
+ {
+ currentThread.interrupt();
+ }
+ }, 50L);
+ // This call would not be interruptable if it wasn't proxied, but we get a StopException
+ // from the proxy.
+ proxy.idle(true);
+ timer.cancel();
+ }
+
+ @Test
+ public void testInterruptTheUninterruptableReturnsDefaultValue()
+ {
+ final String defaultReturnValue = "That's the default return value.";
+ final ITest proxy =
+ MonitoringProxy.create(ITest.class, new TestImpl()).timeoutMillis(1000L).name(
+ THREAD_NAME).errorValueOnInterrupt().errorTypeValueMapping(String.class,
+ defaultReturnValue).get();
+ final Thread currentThread = Thread.currentThread();
+ final Timer timer = new Timer();
+ timer.schedule(new TimerTask()
+ {
+ @Override
+ public void run()
+ {
+ currentThread.interrupt();
+ }
+ }, 50L);
+ // This call would not be interruptable if it wasn't proxied, but we get the default return
+ // value for Strings here.
+ assertEquals(defaultReturnValue, proxy.getString(true));
+ timer.cancel();
+ }
+}
--
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