Transfer Service:

- Rehydration of exception received from target repo


git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@22413 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/transfer/HttpClientTransmitterImpl.java

@@ -35,6 +35,8 @@ import org.alfresco.service.cmr.repository.ContentService;
 import org.alfresco.service.cmr.transfer.TransferException;
 import org.alfresco.service.cmr.transfer.TransferProgress;
 import org.alfresco.service.cmr.transfer.TransferTarget;
+import org.alfresco.util.json.ExceptionJsonSerializer;
+import org.alfresco.util.json.JsonSerializer;
 import org.apache.commons.httpclient.HostConfiguration;
 import org.apache.commons.httpclient.HttpClient;
 import org.apache.commons.httpclient.HttpMethod;
@@ -54,6 +56,7 @@ import org.apache.commons.httpclient.protocol.SSLProtocolSocketFactory;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.json.JSONArray;
+import org.json.JSONException;
 import org.json.JSONObject;
 
 /**
@@ -80,6 +83,8 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
     private Protocol httpProtocol = new Protocol(HTTP_SCHEME_NAME, new DefaultProtocolSocketFactory(), DEFAULT_HTTP_PORT);
     private Protocol httpsProtocol = new Protocol(HTTPS_SCHEME_NAME, (ProtocolSocketFactory) new SSLProtocolSocketFactory(), DEFAULT_HTTPS_PORT);
     private Map<String,Protocol> protocolMap = null;
+    private HttpMethodFactory httpMethodFactory = null;
+    private JsonSerializer<Throwable, JSONObject> jsonErrorSerializer;
     
     private ContentService contentService;
 
@@ -91,6 +96,8 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
 
         httpClient = new HttpClient();
         httpClient.setHttpConnectionManager(new MultiThreadedHttpConnectionManager());
+        httpMethodFactory = new StandardHttpMethodFactoryImpl();
+        jsonErrorSerializer = new ExceptionJsonSerializer();
     }
     
     public void init()
@@ -123,7 +130,7 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
      */
     public void verifyTarget(TransferTarget target) throws TransferException
     {
-        HttpMethod verifyRequest = new PostMethod();
+        HttpMethod verifyRequest = getPostMethod();
         try
         {
             HostConfiguration hostConfig = getHostConfig(target);
@@ -165,8 +172,8 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
                 log.error("Received \"unsuccessful\" response code from target server: " + response);
                 String errorPayload = method.getResponseBodyAsString();
                 JSONObject errorObj = new JSONObject(errorPayload);
-                errorId = errorObj.getString("errorId");
+                errorId = errorObj.getString("alfrescoErrorId");
-                JSONArray errorParamArray = errorObj.getJSONArray("errorParams");
+                JSONArray errorParamArray = errorObj.getJSONArray("alfrescoErrorParams");
                 int length = errorParamArray.length();
                 errorParams = new String[length];
                 for (int i = 0; i < length; ++i) 
@@ -185,7 +192,7 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
      * @param target
      * @return
      */
-    private HttpState getHttpState(TransferTarget target)
+    protected HttpState getHttpState(TransferTarget target)
     {
         HttpState httpState = new HttpState();
         httpState.setCredentials(new AuthScope(target.getEndpointHost(), target.getEndpointPort(), 
@@ -219,7 +226,7 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
 
     public Transfer begin(TransferTarget target) throws TransferException
     {
-        HttpMethod beginRequest = new PostMethod();
+        HttpMethod beginRequest = getPostMethod();
         try
         {
             HostConfiguration hostConfig = getHostConfig(target);
@@ -263,7 +270,7 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
     public void sendManifest(Transfer transfer, File manifest, OutputStream result) throws TransferException
     {
         TransferTarget target = transfer.getTransferTarget();
-        PostMethod postSnapshotRequest = new PostMethod();
+        PostMethod postSnapshotRequest = getPostMethod();
         MultipartRequestEntity requestEntity;
         
         if(log.isDebugEnabled())
@@ -332,7 +339,7 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
     public void abort(Transfer transfer) throws TransferException
     {
         TransferTarget target = transfer.getTransferTarget();
-        HttpMethod abortRequest = new PostMethod();
+        HttpMethod abortRequest = getPostMethod();
         try
         {
             HostConfiguration hostConfig = getHostConfig(target);
@@ -370,7 +377,7 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
     public void commit(Transfer transfer) throws TransferException
     {
         TransferTarget target = transfer.getTransferTarget();
-        HttpMethod commitRequest = new PostMethod();
+        HttpMethod commitRequest = getPostMethod();
         try
         {
             HostConfiguration hostConfig = getHostConfig(target);
@@ -407,7 +414,7 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
     public void prepare(Transfer transfer) throws TransferException
     {
         TransferTarget target = transfer.getTransferTarget();
-        HttpMethod prepareRequest = new PostMethod();
+        HttpMethod prepareRequest = getPostMethod();
         try
         {
             HostConfiguration hostConfig = getHostConfig(target);
@@ -452,7 +459,7 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
         }
 
         TransferTarget target = transfer.getTransferTarget();
-        PostMethod postContentRequest = new PostMethod();
+        PostMethod postContentRequest = getPostMethod();
 
         try
         {
@@ -517,7 +524,7 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
     public TransferProgress getStatus(Transfer transfer) throws TransferException
     {
         TransferTarget target = transfer.getTransferTarget();
-        HttpMethod statusRequest = new PostMethod();
+        HttpMethod statusRequest = getPostMethod();
         try
         {
             HostConfiguration hostConfig = getHostConfig(target);
@@ -539,11 +546,15 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
                 int currentPosition  = statusObj.getInt("currentPosition");
                 int endPosition  = statusObj.getInt("endPosition");
                 String statusStr= statusObj.getString("status");
-                //We're expecting the transfer progress encoded in a JSON object... 
+
+                JSONObject errorJSON = statusObj.getJSONObject("error");
+                Throwable throwable = rehydrateError(errorJSON);
+
                 TransferProgress p = new TransferProgress();
                 p.setStatus(TransferProgress.Status.valueOf(statusStr));
                 p.setCurrentPosition(currentPosition);
                 p.setEndPosition(endPosition);
+                p.setError(throwable);
                 return p;
             } 
             catch (RuntimeException e)
@@ -569,9 +580,7 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
     public void getTransferReport(Transfer transfer, OutputStream result)
     {
         TransferTarget target = transfer.getTransferTarget();
-        PostMethod getReportRequest = new PostMethod();
+        PostMethod getReportRequest = getPostMethod();
-        MultipartRequestEntity requestEntity;
-             
         try
         {
             HostConfiguration hostConfig = getHostConfig(target);
@@ -622,6 +631,24 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
         }        
     }
 
+    protected PostMethod getPostMethod()
+    {
+        return httpMethodFactory.createPostMethod();
+    }
+    
+    /**
+     * 
+     * @param errorJSON A JSON object expected to hold the name of the error class ("errorType"),
+     * the error message ("errorMessage"), and, optionally, the Alfresco message id ("alfrescoErrorId")
+     * and Alfresco message parameters ("alfrescoErrorParams").
+     * @return The rehydrated error object, or null if errorJSON is null.
+     * @throws JSONException if an error occurs while parsing the supplied JSON object
+     */
+    private Throwable rehydrateError(JSONObject errorJSON) 
+    {
+        return jsonErrorSerializer.deserialize(errorJSON);
+    }
+    
     public void setContentService(ContentService contentService)
     {
         this.contentService = contentService;
@@ -631,4 +658,15 @@ public class HttpClientTransmitterImpl implements TransferTransmitter
     {
         return contentService;
     }
-} // end of class
+
+    public void setHttpMethodFactory(HttpMethodFactory httpMethodFactory)
+    {
+        this.httpMethodFactory = httpMethodFactory;
+    }
+
+    public void setJsonErrorSerializer(JsonSerializer<Throwable, JSONObject> jsonErrorSerializer)
+    {
+        this.jsonErrorSerializer = jsonErrorSerializer;
+    }
+    
+}

source/java/org/alfresco/repo/transfer/HttpClientTransmitterImplTest.java

@@ -18,16 +18,21 @@
  */
 package org.alfresco.repo.transfer;
 
+import static org.mockito.Matchers.any;
 import static org.mockito.Mockito.*;
 
 import java.io.IOException;
 import java.net.InetAddress;
 import java.net.Socket;
 import java.net.UnknownHostException;
+import java.util.Arrays;
 
 import junit.framework.TestCase;
 
 import org.alfresco.service.cmr.transfer.TransferException;
+import org.alfresco.service.cmr.transfer.TransferProgress;
+import org.alfresco.service.cmr.transfer.TransferProgress.Status;
+import org.alfresco.util.json.ExceptionJsonSerializer;
 import org.apache.commons.httpclient.ConnectTimeoutException;
 import org.apache.commons.httpclient.HostConfiguration;
 import org.apache.commons.httpclient.HttpClient;
@@ -36,7 +41,10 @@ import org.apache.commons.httpclient.HttpState;
 import org.apache.commons.httpclient.methods.PostMethod;
 import org.apache.commons.httpclient.params.HttpConnectionParams;
 import org.apache.commons.httpclient.protocol.SecureProtocolSocketFactory;
+import org.json.JSONObject;
 import org.mockito.ArgumentCaptor;
+import org.mockito.invocation.InvocationOnMock;
+import org.mockito.stubbing.Answer;
 
 /**
  * Unit test for HttpClientTransmitterImpl
@@ -59,6 +67,7 @@ public class HttpClientTransmitterImplTest extends TestCase
     private HttpClientTransmitterImpl transmitter;
     private HttpClient mockedHttpClient;
     private TransferTargetImpl target;
+    private MockableHttpMethodFactory mockedHttpMethodFactory;
 
     /* (non-Javadoc)
      * @see junit.framework.TestCase#setUp()
@@ -70,7 +79,9 @@ public class HttpClientTransmitterImplTest extends TestCase
         
         this.transmitter = new HttpClientTransmitterImpl();
         this.mockedHttpClient = mock(HttpClient.class);
+        this.mockedHttpMethodFactory = new MockableHttpMethodFactory();
         transmitter.setHttpClient(mockedHttpClient);
+        transmitter.setHttpMethodFactory(mockedHttpMethodFactory);
 
         this.target = new TransferTargetImpl();
         target.setEndpointHost(TARGET_HOST);
@@ -195,6 +206,38 @@ public class HttpClientTransmitterImplTest extends TestCase
         }
     }
     
+    public void testGetStatusErrorRehydration() throws Exception
+    {
+        final ExceptionJsonSerializer errorSerializer = new ExceptionJsonSerializer();
+        final TransferException expectedException = new TransferException("my message id", new Object[] {"param1", "param2"}); 
+        when(mockedHttpClient.executeMethod(any(HostConfiguration.class), any(HttpMethod.class), 
+                any(HttpState.class))).thenReturn(200);
+        doAnswer(new Answer<String>() {
+            @Override
+            public String answer(InvocationOnMock invocation) throws Throwable
+            {
+                JSONObject progressObject = new JSONObject();
+                progressObject.put("transferId", "mytransferid");
+                progressObject.put("status", Status.ERROR);
+                progressObject.put("currentPosition", 1);
+                progressObject.put("endPosition", 10);
+                JSONObject errorObject = errorSerializer.serialize(expectedException);
+                progressObject.put("error", errorObject);
+                return progressObject.toString();
+            }
+        }).when(mockedHttpMethodFactory.latestPostMethod).getResponseBodyAsString();
+        
+        Transfer transfer = new Transfer();
+        transfer.setTransferId("mytransferid");
+        transfer.setTransferTarget(target);
+        TransferProgress progress = transmitter.getStatus(transfer);
+        assertTrue(progress.getError() != null);
+        assertEquals(expectedException.getClass(), progress.getError().getClass());
+        TransferException receivedException = (TransferException)progress.getError();
+        assertEquals(expectedException.getMsgId(), receivedException.getMsgId());
+        assertTrue(Arrays.deepEquals(expectedException.getMsgParams(), receivedException.getMsgParams()));
+    }
+    
     private static class CustomSocketFactory implements SecureProtocolSocketFactory 
     {
 
@@ -236,6 +279,26 @@ public class HttpClientTransmitterImplTest extends TestCase
             // TODO Auto-generated method stub
             return null;
         }
+    }
     
+    private static class MockableHttpMethodFactory implements HttpMethodFactory
+    {
+        private PostMethod latestPostMethod;
+        
+        public MockableHttpMethodFactory()
+        {
+            reset();
+        }
+        
+        @Override
+        public PostMethod createPostMethod()
+        {
+            return latestPostMethod;
+        }
+        
+        public void reset()
+        {
+            latestPostMethod = spy(new PostMethod());; 
+        }
     }
 }

source/java/org/alfresco/repo/transfer/HttpMethodFactory.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2009-2010 Alfresco Software Limited.
+ *
+ * This file is part of Alfresco
+ *
+ * Alfresco is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Alfresco is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.alfresco.repo.transfer;
+
+import org.apache.commons.httpclient.methods.PostMethod;
+
+public interface HttpMethodFactory
+{
+    PostMethod createPostMethod();
+}

source/java/org/alfresco/repo/transfer/StandardHttpMethodFactoryImpl.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2009-2010 Alfresco Software Limited.
+ *
+ * This file is part of Alfresco
+ *
+ * Alfresco is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Alfresco is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.alfresco.repo.transfer;
+
+import org.apache.commons.httpclient.methods.PostMethod;
+
+public class StandardHttpMethodFactoryImpl implements HttpMethodFactory
+{
+
+    @Override
+    public PostMethod createPostMethod()
+    {
+        return new PostMethod();
+    }
+
+}

source/java/org/alfresco/repo/transfer/TransferServiceCallbackTest.java

@@ -58,6 +58,7 @@ import org.alfresco.service.cmr.transfer.TransferEventSendingContent;
 import org.alfresco.service.cmr.transfer.TransferEventSendingSnapshot;
 import org.alfresco.service.cmr.transfer.TransferEventSuccess;
 import org.alfresco.service.cmr.transfer.TransferException;
+import org.alfresco.service.cmr.transfer.TransferFailureException;
 import org.alfresco.service.cmr.transfer.TransferProgress;
 import org.alfresco.service.cmr.transfer.TransferService2;
 import org.alfresco.service.cmr.transfer.TransferTarget;
@@ -293,7 +294,7 @@ public class TransferServiceCallbackTest extends TestCase
         verifyCallback(expectedEvents);
     }
     
-    public void xtestErrorDuringCommit()
+    public void testErrorDuringCommit()
     {
         Exception error = new TransferException("Commit failed");
         
@@ -329,8 +330,13 @@ public class TransferServiceCallbackTest extends TestCase
 
         TransferDefinition transferDef = new TransferDefinition();
         transferDef.setNodes(folder1, file1, file2, file3);
+        try
+        {
             transferService.transfer(TRANSFER_TARGET_NAME, transferDef, mockedCallback);
-
+            fail();
+        }
+        catch (TransferFailureException ex)
+        {
             List<TransferEvent> expectedEvents = new ArrayList<TransferEvent>();
             TransferEventImpl event;
     
@@ -406,6 +412,14 @@ public class TransferServiceCallbackTest extends TestCase
             event.setTransferState(TransferState.COMMITTING);
             expectedEvents.add(event);
             
+            event = new TransferEventReport();
+            event.setTransferState(TransferState.COMMITTING);
+            expectedEvents.add(event);
+            
+            event = new TransferEventReport();
+            event.setTransferState(TransferState.COMMITTING);
+            expectedEvents.add(event);
+    
             event = new TransferEventEndState();
             event.setTransferState(TransferState.COMMITTING);
             expectedEvents.add(event);
@@ -419,14 +433,9 @@ public class TransferServiceCallbackTest extends TestCase
             ((TransferEventError)event).setException(error);
             expectedEvents.add(event);
     
-        event = new TransferEventReport();
-        expectedEvents.add(event);
-        
-        event = new TransferEventReport();
-        expectedEvents.add(event);
-
             verifyCallback(expectedEvents);
         }
+    }
     
     public void testTargetAlreadyLocked()
     {
@@ -440,7 +449,7 @@ public class TransferServiceCallbackTest extends TestCase
             transferService.transfer(TRANSFER_TARGET_NAME, transferDef, mockedCallback);
             fail("Transfer expected to throw an exception, but it didn't.");
         }
-        catch(TransferException ex)
+        catch(TransferFailureException ex)
         {
             List<TransferEvent> expectedEvents = new ArrayList<TransferEvent>();
             TransferEventImpl event;
@@ -467,7 +476,7 @@ public class TransferServiceCallbackTest extends TestCase
 
             event = new TransferEventError();
             event.setTransferState(TransferState.ERROR);
-            ((TransferEventError)event).setException(ex);
+            ((TransferEventError)event).setException((Exception)ex.getCause());
             expectedEvents.add(event);
             
             verifyCallback(expectedEvents);

source/java/org/alfresco/repo/transfer/TransferServiceImpl2.java

@@ -674,7 +674,14 @@ public class TransferServiceImpl2 implements TransferService2
                             {
                                 targetError = new TransferException(MSG_UNKNOWN_TARGET_ERROR);
                             }
+                            if (Exception.class.isAssignableFrom(targetError.getClass()))
+                            {
+                                failureException = (Exception)targetError;
+                            }
+                            else
+                            {
                                 failureException = new TransferException(MSG_TARGET_ERROR, new Object[] {targetError.getMessage()}, targetError);
+                            }
                             clientState = ClientTransferState.Finished;
                             break;
                         }

source/java/org/alfresco/util/json/ExceptionJsonSerializer.java

@@ -0,0 +1,170 @@
+/*
+ * Copyright (C) 2005-2010 Alfresco Software Limited.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+ * As a special exception to the terms and conditions of version 2.0 of 
+ * the GPL, you may redistribute this Program in connection with Free/Libre 
+ * and Open Source Software ("FLOSS") applications as described in Alfresco's 
+ * FLOSS exception.  You should have recieved a copy of the text describing 
+ * the FLOSS exception, and it is also available here: 
+ * http://www.alfresco.com/legal/licensing"
+ */
+package org.alfresco.util.json;
+
+import java.lang.reflect.Constructor;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import org.alfresco.error.AlfrescoRuntimeException;
+import org.alfresco.service.cmr.transfer.TransferException;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+public class ExceptionJsonSerializer implements JsonSerializer<Throwable, JSONObject>
+{
+    private final static Log log = LogFactory.getLog(ExceptionJsonSerializer.class);
+    
+    @Override
+    public Throwable deserialize(JSONObject errorJSON)
+    {
+        if (errorJSON == null)
+        {
+            return null;
+        }
+        
+        Throwable result = null;
+        Object createdObject = null;
+        
+        try
+        {
+            //errorType and errorMessage should always be reported
+            String errorType = errorJSON.getString("errorType");
+            String errorMessage = errorJSON.getString("errorMessage");
+            
+            if (errorType == null)
+            {
+                errorType = Exception.class.getName();
+            }
+            if (errorMessage == null)
+            {
+                errorMessage = "";
+            }
+            //alfrescoErrorId and alfrescoErrorParams will only appear if the
+            //throwable object was of a subclass of AlfrescoRuntimeException
+            String errorId = errorJSON.optString("alfrescoMessageId", null);
+            Object[] errorParams = new Object[0];
+            JSONArray errorParamArray = errorJSON.optJSONArray("alfrescoMessageParams");
+            if (errorParamArray != null)
+            {
+                int length = errorParamArray.length();
+                errorParams = new Object[length];
+                for (int i = 0; i < length; ++i) 
+                {
+                    errorParams[i] = errorParamArray.getString(i);
+                }
+            }
+            Class<?> errorClass;
+            try
+            {
+                errorClass = Class.forName(errorType);
+            }
+            catch (ClassNotFoundException e)
+            {
+                errorClass = Exception.class;
+            }
+            Constructor<?> constructor = null;
+            try
+            {
+                try
+                {
+                    constructor = errorClass.getConstructor(String.class, Object[].class);
+                    createdObject = constructor.newInstance(errorId, errorParams);
+                }
+                catch (NoSuchMethodException e)
+                {
+                    try
+                    {
+                        constructor = errorClass.getConstructor(String.class);
+                        createdObject = constructor.newInstance(errorId == null ? errorMessage : errorId);
+                    }
+                    catch (NoSuchMethodException e1)
+                    {
+                        try
+                        {
+                            constructor = errorClass.getConstructor();
+                            createdObject = constructor.newInstance();
+                        }
+                        catch (NoSuchMethodException e2)
+                        {
+                        }
+                    }
+                }
+            }
+            catch(Exception ex)
+            {
+                //We don't need to do anything here. Code below will fix things up
+            }
+            if (createdObject == null || !Throwable.class.isAssignableFrom(createdObject.getClass()))
+            {
+                result = new TransferException(errorId == null ? errorMessage : errorId, errorParams);
+            }
+            else
+            {
+                result = (Throwable)createdObject;
+            }
+        }
+        catch(JSONException ex)
+        {
+            if (log.isDebugEnabled())
+            {
+                log.debug("Failed to deserialize Throwable object from JSON object", ex);
+            }
+        }
+        return result;
+    }
+
+    @Override
+    public JSONObject serialize(Throwable object)
+    {
+        JSONObject errorObject = new JSONObject();
+        
+        try
+        {
+            errorObject.put("errorType", object.getClass().getName());
+            errorObject.put("errorMessage", object.getMessage());
+            if (AlfrescoRuntimeException.class.isAssignableFrom(object.getClass()))
+            {
+                AlfrescoRuntimeException alfEx = (AlfrescoRuntimeException)object;
+                errorObject.put("alfrescoMessageId", alfEx.getMsgId());
+                Object[] msgParams = alfEx.getMsgParams();
+                List<Object> params = msgParams == null ? Collections.emptyList() : Arrays.asList(msgParams);
+                errorObject.put("alfrescoMessageParams", params);
+            }
+        }
+        catch (JSONException e)
+        {
+            if (log.isDebugEnabled())
+            {
+                log.debug("Failed to serialize Throwable object into JSON object", e);
+            }
+        }
+        return errorObject;
+    }
+}

source/java/org/alfresco/util/json/ExceptionJsonSerializerTest.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2005-2010 Alfresco Software Limited.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+ * As a special exception to the terms and conditions of version 2.0 of 
+ * the GPL, you may redistribute this Program in connection with Free/Libre 
+ * and Open Source Software ("FLOSS") applications as described in Alfresco's 
+ * FLOSS exception.  You should have recieved a copy of the text describing 
+ * the FLOSS exception, and it is also available here: 
+ * http://www.alfresco.com/legal/licensing"
+ */
+package org.alfresco.util.json;
+
+import java.util.Arrays;
+
+import junit.framework.TestCase;
+
+import org.alfresco.error.AlfrescoRuntimeException;
+import org.alfresco.repo.security.permissions.AccessDeniedException;
+import org.json.JSONObject;
+
+
+public class ExceptionJsonSerializerTest extends TestCase
+{
+    
+    private ExceptionJsonSerializer serializer;
+
+    @Override
+    protected void setUp() throws Exception
+    {
+        super.setUp();
+        serializer = new ExceptionJsonSerializer();
+    }
+
+    public void testIllegalArgumentException()
+    {
+        Exception expectedException = new IllegalArgumentException("This is the message");
+        JSONObject obj = serializer.serialize(expectedException);
+        Throwable actualException = serializer.deserialize(obj);
+        assertEquals(expectedException.getClass(), actualException.getClass());
+        assertEquals(expectedException.getMessage(), actualException.getMessage());
+    }
+
+    public void testAlfrescoRuntimeExceptionWithNoParams()
+    {
+        AlfrescoRuntimeException expectedException = new AlfrescoRuntimeException("message id");
+        JSONObject obj = serializer.serialize(expectedException);
+        Throwable actualException = serializer.deserialize(obj);
+        assertEquals(expectedException.getClass(), actualException.getClass());
+        assertEquals(expectedException.getMsgId(), ((AlfrescoRuntimeException)actualException).getMsgId());
+        assertTrue(((AlfrescoRuntimeException)actualException).getMsgParams().length == 0);
+    }
+
+    public void testAlfrescoRuntimeExceptionWithParams()
+    {
+        AlfrescoRuntimeException expectedException = new AlfrescoRuntimeException("message id", 
+                new Object[]{"one","two","three"});
+        JSONObject obj = serializer.serialize(expectedException);
+        Throwable actualException = serializer.deserialize(obj);
+        assertEquals(expectedException.getClass(), actualException.getClass());
+        assertEquals(expectedException.getMsgId(), ((AlfrescoRuntimeException)actualException).getMsgId());
+        assertTrue(Arrays.deepEquals(expectedException.getMsgParams(), 
+                ((AlfrescoRuntimeException)actualException).getMsgParams()));
+    }
+
+    public void testAccessDeniedException()
+    {
+        AccessDeniedException expectedException = new AccessDeniedException("message id");
+        JSONObject obj = serializer.serialize(expectedException);
+        Throwable actualException = serializer.deserialize(obj);
+        assertEquals(expectedException.getClass(), actualException.getClass());
+        assertEquals(expectedException.getMsgId(), ((AlfrescoRuntimeException)actualException).getMsgId());
+        assertTrue(expectedException.getMsgParams() == null);
+    }
+}