clone exceptions before fixing instead of mutating in place. I stand by all naming conventions used in this commit.

Author: David R. MacIver

src/com/rabbitmq/client/ShutdownSignalException.java

@@ -30,6 +30,8 @@
 //
 package com.rabbitmq.client;
 
+import com.rabbitmq.utility.SensibleClone;
+
 /**
  * Encapsulates a shutdown condition for a connection to an AMQP broker.
  * Depending on HardError when calling
@@ -38,7 +40,7 @@
  * this exception.
  */
 
-public class ShutdownSignalException extends RuntimeException {
+public class ShutdownSignalException extends RuntimeException implements SensibleClone<ShutdownSignalException>{
     /** True if the connection is shut down, or false if this signal refers to a channel */
     private final boolean _hardError;
 
@@ -92,6 +94,14 @@ public ShutdownSignalException(boolean hardError,
     /** @return Reference to Connection or Channel object that fired the signal **/
     public Object getReference() { return _ref; }
 
+    public ShutdownSignalException sensibleClone(){
+        try {
+            return (ShutdownSignalException)super.clone();
+        } catch (CloneNotSupportedException e){
+            // You've got to be kidding me
+            throw new Error(e);
+        }
+    }
 }
 
 

src/com/rabbitmq/utility/BlockingValueOrException.java

@@ -32,7 +32,7 @@
 
 import java.util.concurrent.TimeoutException;
 
-public class BlockingValueOrException<V, E extends Throwable>
+public class BlockingValueOrException<V, E extends Throwable & SensibleClone<E>>
     extends BlockingCell<ValueOrException<V, E>>
 {
     public void setValue(V v) {

src/com/rabbitmq/utility/Utility.java

@@ -50,7 +50,9 @@ public ThrowableCreatedElsewhere(Throwable throwable){
         } 
     }
 
-    public static <T extends Throwable> T fixStackTrace(T throwable){
+    public static <T extends Throwable & SensibleClone<T>> T fixStackTrace(T throwable){
+      throwable = throwable.sensibleClone();
+
       if(throwable.getCause() == null){
         // We'd like to preserve the original stack trace in the cause.
         // Unfortunately Java doesn't let you set the cause once it's been

src/com/rabbitmq/utility/ValueOrException.java

@@ -30,7 +30,7 @@
 //
 package com.rabbitmq.utility;
 
-public class ValueOrException<V, E extends Throwable> {
+public class ValueOrException<V, E extends Throwable & SensibleClone<E>> {
     private final boolean _useValue;
     private final V _value;
     private final E _exception;
@@ -57,7 +57,7 @@ private ValueOrException(V value, E exception, boolean useValue) {
      * @param value the value to wrap as a ValueOrException
      * @return the wrapped value
      */
-    public static <V, E extends Throwable> ValueOrException<V, E> makeValue(V value) {
+    public static <V, E extends Throwable & SensibleClone<E>> ValueOrException<V, E> makeValue(V value) {
         return new ValueOrException<V, E>(value, null, true);
     }
 
@@ -66,7 +66,7 @@ public static <V, E extends Throwable> ValueOrException<V, E> makeValue(V value)
      * @param exception the exception to wrap as a ValueOrException
      * @return the wrapped exception
      */
-    public static <V, E extends Throwable> ValueOrException<V, E> makeException(E exception) {
+    public static <V, E extends Throwable & SensibleClone<E>> ValueOrException<V, E> makeException(E exception) {
         return new ValueOrException<V, E>(null, exception, false);
     }
 

test/src/com/rabbitmq/client/test/ValueOrExceptionTest.java

@@ -30,39 +30,50 @@
 //
 package com.rabbitmq.client.test;
 
-import java.io.IOException;
-
 import junit.framework.TestCase;
 import junit.framework.TestSuite;
 
 import com.rabbitmq.utility.ValueOrException;
+import com.rabbitmq.utility.SensibleClone;
 
 
 public class ValueOrExceptionTest extends TestCase {
+    public static class InsufficientMagicException extends Exception implements SensibleClone<InsufficientMagicException>{
+      public InsufficientMagicException(String message){
+        super(message);
+      }
+
+      public InsufficientMagicException sensibleClone(){
+        return new InsufficientMagicException(getMessage());
+      }
+    }
+
+
     public static TestSuite suite()
     {
         TestSuite suite = new TestSuite("valueOrEx");
         suite.addTestSuite(ValueOrExceptionTest.class);
         return suite;
     }
 
-    public void testStoresValue() throws IOException {
+    public void testStoresValue() throws InsufficientMagicException {
         Integer value = new Integer(3);
-        ValueOrException<Integer, IOException> valueOrEx = ValueOrException.<Integer, IOException>makeValue(value);
+        ValueOrException<Integer, InsufficientMagicException> valueOrEx = ValueOrException.<Integer, InsufficientMagicException>makeValue(value);
 
         Integer returnedValue = valueOrEx.getValue();
         assertTrue(returnedValue == value);
     }
 
-    public void testStoresException() {
-        IOException exception = new IOException("dummy message");
-        ValueOrException<Integer, IOException> valueOrEx = ValueOrException.<Integer, IOException>makeException(exception);
+    public void testClonesException() {
+        InsufficientMagicException exception = new InsufficientMagicException("dummy message");
+        ValueOrException<Integer, InsufficientMagicException> valueOrEx = ValueOrException.<Integer, InsufficientMagicException>makeException(exception);
 
         try {
             valueOrEx.getValue();
             fail("Expected exception");
-        } catch(IOException returnedException) {
-            assertTrue(returnedException == exception);
+        } catch(InsufficientMagicException returnedException) {
+            assertTrue(returnedException != exception);
+            assertEquals(returnedException.getMessage(), exception.getMessage());
         }
     }
 }