DATADOC-4 - Improved MongoTemplate exception handling

- moved exception translation from MongoDbUtils to MongoExceptionTranslator
- don't let MongoFactoryBean implement PersistenceExceptionTranslator
- heavily refactored MongoTemplate to let higher level methods use callbacks to centralize exception handling in the callback executing methods
- changed return type of MongoOperations.getCollectionNames to Set<String> as returning a List implies same order, that we can't guarantee actually
- polished JavaDoc of MongoOperations
- added assertions to methods
- changed methods taking a List<Object> to take a List<? extends Object> instead
- added abstract unit test for MongoOperations to define tests regarding expected exception behavior
- let MongoTemplateUnitTests extend MongoOperationsUnitTests

spring-data-mongodb/src/main/java/org/springframework/data/document/mongodb/MongoDbUtils.java

@@ -18,18 +18,11 @@ package org.springframework.data.document.mongodb;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.springframework.dao.DataAccessException;
-import org.springframework.dao.DataAccessResourceFailureException;
-import org.springframework.dao.DataIntegrityViolationException;
-import org.springframework.data.document.UncategorizedDocumentStoreException;
 import org.springframework.transaction.support.TransactionSynchronizationManager;
 import org.springframework.util.Assert;
 
 import com.mongodb.DB;
 import com.mongodb.Mongo;
-import com.mongodb.MongoException;
-import com.mongodb.MongoException.DuplicateKey;
-import com.mongodb.MongoException.Network;
 
 /**
  * Helper class featuring helper methods for internal MongoDb classes.
@@ -53,36 +46,6 @@ abstract class MongoDbUtils {
 		
 	}
 
-	/**
-	 * Convert the given runtime exception to an appropriate exception from the
-	 * <code>org.springframework.dao</code> hierarchy.
-	 * Return null if no translation is appropriate: any other exception may
-	 * have resulted from user code, and should not be translated.
-	 * @param ex runtime exception that occurred
-	 * @return the corresponding DataAccessException instance,
-	 * or <code>null</code> if the exception should not be translated
-	 */
-	public static DataAccessException translateMongoExceptionIfPossible(RuntimeException ex) {
-
-		// Check for well-known MongoException subclasses.
-		
-		// All other MongoExceptions
-		if(ex instanceof DuplicateKey) {
-			return new DataIntegrityViolationException(ex.getMessage(),ex);
-		}
-		if(ex instanceof Network) {
-			return new DataAccessResourceFailureException(ex.getMessage(), ex);
-		}
-		if (ex instanceof MongoException) {
-			return new UncategorizedDocumentStoreException(ex.getMessage(), ex);
-		}
-		
-		// If we get here, we have an exception that resulted from user code,
-		// rather than the persistence provider, so we return null to indicate
-		// that translation should not occur.
-		return null;				
-	}
-
 	/**
 	 * Obtains a {@link DB} connection for the given {@link Mongo} instance and database name
 	 * 

spring-data-mongodb/src/main/java/org/springframework/data/document/mongodb/MongoExceptionTranslator.java

@@ -16,11 +16,22 @@
 package org.springframework.data.document.mongodb;
 
 import org.springframework.dao.DataAccessException;
+import org.springframework.dao.DataAccessResourceFailureException;
+import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.dao.support.PersistenceExceptionTranslator;
+import org.springframework.data.document.UncategorizedDocumentStoreException;
 
+import com.mongodb.MongoException;
+import com.mongodb.MongoException.DuplicateKey;
+import com.mongodb.MongoException.Network;
 
 /**
- * Simple {@link PersistenceExceptionTranslator} for Mongo.
+ * Simple {@link PersistenceExceptionTranslator} for Mongo. Convert the given runtime exception to an appropriate
+ * exception from the {@code org.springframework.dao} hierarchy. Return {@literal null} if no translation is
+ * appropriate: any other exception may have resulted from user code, and should not be translated.
+ * @param ex runtime exception that occurred
+ * @return the corresponding DataAccessException instance, or {@literal null} if the exception should not be translated
+ * 
  * 
  * @author Oliver Gierke
  */
@@ -34,6 +45,22 @@ public class MongoExceptionTranslator implements PersistenceExceptionTranslator
 	 */
 	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
 
-        return MongoDbUtils.translateMongoExceptionIfPossible(ex);
+		// Check for well-known MongoException subclasses.
+
+		// All other MongoExceptions
+		if (ex instanceof DuplicateKey) {
+			return new DataIntegrityViolationException(ex.getMessage(), ex);
+		}
+		if (ex instanceof Network) {
+			return new DataAccessResourceFailureException(ex.getMessage(), ex);
+		}
+		if (ex instanceof MongoException) {
+			return new UncategorizedDocumentStoreException(ex.getMessage(), ex);
+		}
+
+		// If we get here, we have an exception that resulted from user code,
+		// rather than the persistence provider, so we return null to indicate
+		// that translation should not occur.
+		return null;
 	}
 }

spring-data-mongodb/src/main/java/org/springframework/data/document/mongodb/MongoFactoryBean.java

@@ -22,8 +22,6 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.InitializingBean;
-import org.springframework.dao.DataAccessException;
-import org.springframework.dao.support.PersistenceExceptionTranslator;
 import org.springframework.util.Assert;
 
 import com.mongodb.Mongo;
@@ -38,8 +36,7 @@ import com.mongodb.ServerAddress;
  * 
  * @since 1.0
  */
-public class MongoFactoryBean implements FactoryBean<Mongo>, InitializingBean, 
+public class MongoFactoryBean implements FactoryBean<Mongo>, InitializingBean {
-		PersistenceExceptionTranslator {
 
 	
 	/**
@@ -120,10 +117,4 @@ public class MongoFactoryBean implements FactoryBean<Mongo>, InitializingBean,
 			}
 		}
 	}
-
-	public DataAccessException translateExceptionIfPossible(RuntimeException ex) {
-		logger.debug("Translating " + ex);
-		return MongoDbUtils.translateMongoExceptionIfPossible(ex);
-	}
-
 }

spring-data-mongodb/src/main/java/org/springframework/data/document/mongodb/MongoOperations.java

@@ -16,6 +16,7 @@
 package org.springframework.data.document.mongodb;
 
 import java.util.List;
+import java.util.Set;
 
 import com.mongodb.DBCollection;
 import com.mongodb.DBObject;
@@ -27,7 +28,7 @@ import com.mongodb.DBObject;
  * 
  * @author Thomas Risberg
  * @author Mark Pollack
- *
+ * @author Oliver Gierke
  */
 public interface MongoOperations {
 
@@ -38,7 +39,7 @@ public interface MongoOperations {
 	String getDefaultCollectionName();
 
 	/**
-	 * The default collection used by this template
+	 * The default collection used by this template.
 	 * @return The default collection used by this template
 	 */
 	DBCollection getDefaultCollection();
@@ -117,17 +118,17 @@ public interface MongoOperations {
 	DBCollection createCollection(String collectionName);
 
 	/**
-	 * Create a collect with the provided name and options
+	 * Create a collect with the provided name and options.
 	 * @param collectionName name of the collection
 	 * @param collectionOptions options to use when creating the collection.
 	 */
 	void createCollection(String collectionName, CollectionOptions collectionOptions);
 
 	/**
-	 * A list of collection names
+	 * A set of collection names.
 	 * @return list of collection names
 	 */
-	List<String> getCollectionNames();
+	Set<String> getCollectionNames();
 	
 	/**
 	 * Get a collection by name, creating it if it doesn't exist.
@@ -216,14 +217,14 @@ public interface MongoOperations {
 	 * 
 	 * @param listToSave the list of objects to save.
 	 */
-	void insertList(List<Object> listToSave);
+	void insertList(List<? extends Object> listToSave);
 
 	/**
 	 * Insert a list of objects into the specified collection in a single batch write to the database.
 	 * @param collectionName name of the collection to store the object in 
 	 * @param listToSave the list of objects to save.
 	 */
-	void insertList(String collectionName, List<Object> listToSave);
+	void insertList(String collectionName, List<? extends Object> listToSave);
 
 	/**
 	 * Insert a list of objects into the specified collection using the provided MongoWriter instance
@@ -233,7 +234,7 @@ public interface MongoOperations {
 	 * @param listToSave the list of objects to save.
 	 * @param writer the writer to convert the object to save into a DBObject
 	 */
-	<T> void insertList(String collectionName, List<T> listToSave, MongoWriter<T> writer);
+	<T> void insertList(String collectionName, List<? extends T> listToSave, MongoWriter<T> writer);
 
 	/**
 	 * Save the object to the default collection.  This will perform an insert if the object is not already 

spring-data-mongodb/src/main/java/org/springframework/data/document/mongodb/MongoTemplate.java

@@ -16,19 +16,20 @@
 
 package org.springframework.data.document.mongodb;
 
-import static java.lang.String.*;
-
 import java.beans.PropertyDescriptor;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
+import java.util.Set;
 
 import org.bson.types.ObjectId;
 import org.springframework.beans.BeanUtils;
 import org.springframework.beans.BeanWrapper;
 import org.springframework.beans.PropertyAccessorFactory;
 import org.springframework.beans.factory.InitializingBean;
-import org.springframework.dao.DataRetrievalFailureException;
+import org.springframework.dao.DataAccessException;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
+import org.springframework.jca.cci.core.ConnectionCallback;
 import org.springframework.util.Assert;
 
 import com.mongodb.BasicDBObject;
@@ -39,7 +40,6 @@ import com.mongodb.DBCursor;
 import com.mongodb.DBObject;
 import com.mongodb.Mongo;
 import com.mongodb.MongoException;
-import com.mongodb.WriteResult;
 import com.mongodb.util.JSON;
 
 /**
@@ -53,10 +53,10 @@ import com.mongodb.util.JSON;
 public class MongoTemplate implements InitializingBean, MongoOperations {
 	
 	private static final String ID = "_id";
-	private static final String COLLECTION_ERROR_TEMPLATE = "Error creating collection %s: %s";
 
 	private final MongoConverter mongoConverter;
 	private final Mongo mongo;
+	private final MongoExceptionTranslator exceptionTranslator = new MongoExceptionTranslator();
 	
 	private String defaultCollectionName;
 	private String databaseName;
@@ -98,7 +98,7 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 	}
 
 	/**
-	 * Sets the password to use to authenticate with the Mongo database
+	 * Sets the password to use to authenticate with the Mongo database.
 	 * 
 	 * @param password The password to use
 	 */
@@ -107,10 +107,20 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 		this.password = password;
 	}
 
+	/**
+	 * Sets the name of the default collection to be used.
+	 * 
+	 * @param defaultCollectionName
+	 */
 	public void setDefaultCollectionName(String defaultCollectionName) {
 		this.defaultCollectionName = defaultCollectionName;
 	}
 
+	/**
+	 * Sets the database name to be used.
+	 * 
+	 * @param databaseName
+	 */
 	public void setDatabaseName(String databaseName) {
 		Assert.notNull(databaseName);
 		this.databaseName = databaseName;
@@ -127,7 +137,12 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 	 * @see org.springframework.data.document.mongodb.MongoOperations#getDefaultCollection()
 	 */
 	public DBCollection getDefaultCollection() {
-		return getDb().getCollection(getDefaultCollectionName());
+		
+		return execute(new DBCallback<DBCollection>() {
+			public DBCollection doInDB(DB db) throws MongoException, DataAccessException {
+				return db.getCollection(getDefaultCollectionName());
+			}
+		});
 	}
 
 	/* (non-Javadoc)
@@ -140,33 +155,41 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#executeCommand(com.mongodb.DBObject)
 	 */
-	public void executeCommand(DBObject command) {
+	public void executeCommand(final DBObject command) {
-		CommandResult cr = getDb().command(command);
+		
-		String err = cr.getErrorMessage();
+		CommandResult result = execute(new DBCallback<CommandResult>() {
-		if (err != null) {
+			public CommandResult doInDB(DB db) throws MongoException, DataAccessException {
+				return db.command(command);
+			}
+		});
+		
+		String error = result.getErrorMessage();
+		if (error != null) {
 			throw new InvalidDataAccessApiUsageException("Command execution of " +
-					command.toString() + " failed: " + err);
+					command.toString() + " failed: " + error);
 		}
 	}
 	
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#execute(org.springframework.data.document.mongodb.DBCallback)
 	 */
-	public <T> T execute(DBCallback<T> action) {
+	public <T> T execute(DbCallback<T> action) {
-		DB db = getDb();
+		
+		Assert.notNull(action);
 		
 		try {
+			DB db = getDb();
 			return action.doInDB(db);
 		} catch (MongoException e) {
-			throw MongoDbUtils.translateMongoExceptionIfPossible(e);
+			throw potentiallyConvertRuntimeException(e);
 		}
 	}
 
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#execute(org.springframework.data.document.mongodb.CollectionCallback)
 	 */
-	public <T> T execute(CollectionCallback<T> action) {
+	public <T> T execute(CollectionCallback<T> callback) {
-		return execute(action, defaultCollectionName);
+		return execute(callback, defaultCollectionName);
 	}
 
 	/* (non-Javadoc)
@@ -174,79 +197,126 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 	 */
 	public <T> T execute(CollectionCallback<T> callback, String collectionName) {
 
+		Assert.notNull(callback);
+		
 		try {
-			return callback.doInCollection(getCollection(collectionName));
+			DBCollection collection = getDb().getCollection(collectionName);
+			return callback.doInCollection(collection);
 		} catch (MongoException e) {
-			throw MongoDbUtils.translateMongoExceptionIfPossible(e);
+			throw potentiallyConvertRuntimeException(e);
+		}
+	}
+	
+	/**
+	 * Central callback executing method to do queries against the datastore that requires reading a collection of
+	 * objects. It will take the following steps <ol> <li>Execute the given {@link ConnectionCallback} for a
+	 * {@link DBCursor}.</li> <li>Prepare that {@link DBCursor} with the given {@link CursorPreparer} (will be skipped
+	 * if {@link CursorPreparer} is {@literal null}</li> <li>Iterate over the {@link DBCursor} and applies the given
+	 * {@link DbObjectCallback} to each of the {@link DBObject}s collecting the actual result {@link List}.</li> <ol>
+	 * 
+	 * @param <T>
+	 * @param collectionCallback the callback to retrieve the {@link DBCursor} with
+	 * @param preparer the {@link CursorPreparer} to potentially modify the {@link DBCursor} before ireating over it
+	 * @param objectCallback the {@link DbObjectCallback} to transform {@link DBObject}s into the actual domain type
+	 * @param collectionName the collection to be queried
+	 * @return
+	 */
+	private <T> List<T> executeEach(CollectionCallback<DBCursor> collectionCallback, CursorPreparer preparer,
+			DbObjectCallback<T> objectCallback, String collectionName) {
+		
+		try {
+			DBCursor cursor = collectionCallback.doInCollection(getCollection(collectionName));
+			
+			if (preparer != null) {
+				preparer.prepare(cursor);
+			}
+			
+			List<T> result = new ArrayList<T>();
+			
+			for (DBObject object : cursor) {
+				result.add(objectCallback.doWith(object));
+			}
+			
+			return result;
+		} catch (MongoException e) {
+			throw potentiallyConvertRuntimeException(e);
 		}
 	}
 
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#executeInSession(org.springframework.data.document.mongodb.DBCallback)
 	 */
-	public <T> T executeInSession(DBCallback<T> action) {
+	public <T> T executeInSession(final DBCallback<T> action) {
-		DB db = getDb();
+		
-		db.requestStart();
+		return execute(new DBCallback<T>() {
+			public T doInDB(DB db) throws MongoException, DataAccessException {
 				try {
+					db.requestStart();
 					return action.doInDB(db);
-		} catch (MongoException e) {
-			throw MongoDbUtils.translateMongoExceptionIfPossible(e);
 				} finally {
 					db.requestDone();
 				}
 			}
+		});
+	}
 	
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#createCollection(java.lang.String)
 	 */
-	public DBCollection createCollection(String collectionName) {
+	public DBCollection createCollection(final String collectionName) {
-		try {
+		return execute(new DBCallback<DBCollection>() {
-			return getDb().createCollection(collectionName, new BasicDBObject());
+			public DBCollection doInDB(DB db) throws MongoException, DataAccessException {
-		} catch (MongoException e) {
+				return db.createCollection(collectionName, new BasicDBObject());
-			throw new InvalidDataAccessApiUsageException(format(COLLECTION_ERROR_TEMPLATE, collectionName, e.getMessage()), e);
 			}
+		});
 	}
 		
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#createCollection(java.lang.String, org.springframework.data.document.mongodb.CollectionOptions)
 	 */
-	public void createCollection(String collectionName, CollectionOptions collectionOptions) {
+	public void createCollection(final String collectionName, final CollectionOptions collectionOptions) {
-		try {
+		execute(new DBCallback<Void>() {
-			getDb().createCollection(collectionName, convertToDbObject(collectionOptions));
+			public Void doInDB(DB db) throws MongoException, DataAccessException {
-		} catch (MongoException e) {
+				db.createCollection(collectionName, convertToDbObject(collectionOptions));
-			throw new InvalidDataAccessApiUsageException(format(COLLECTION_ERROR_TEMPLATE, collectionName, e.getMessage()), e);
+				return null;
 			}
+		});
 	}
 	
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#getCollection(java.lang.String)
 	 */
-	public DBCollection getCollection(String collectionName) {
+	public DBCollection getCollection(final String collectionName) {
-		try {
+		return execute(new DBCallback<DBCollection>() {
-			return getDb().getCollection(collectionName);
+			public DBCollection doInDB(DB db) throws MongoException, DataAccessException {
-		} catch (MongoException e) {
+				return db.getCollection(collectionName);
-			throw new InvalidDataAccessApiUsageException(format(COLLECTION_ERROR_TEMPLATE, collectionName, e.getMessage()), e);
 			}
+		});
 	}
 		
 
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#collectionExists(java.lang.String)
 	 */
-	public boolean collectionExists(String collectionName) {
+	public boolean collectionExists(final String collectionName) {
-		try {
+		return execute(new DBCallback<Boolean>() {
-			return getDb().collectionExists(collectionName);
+			public Boolean doInDB(DB db) throws MongoException, DataAccessException {
-		} catch (MongoException e) {
+				return db.collectionExists(collectionName);
-			throw new InvalidDataAccessApiUsageException("Error creating collection " + collectionName + ": " + e.getMessage(), e);
 			}
+		});
 	}
 
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#dropCollection(java.lang.String)
 	 */
 	public void dropCollection(String collectionName) {
-		getDb().getCollection(collectionName)
+		
-			.drop();
+		execute(new CollectionCallback<Void>() {
+			public Void doInCollection(DBCollection collection) throws MongoException, DataAccessException {
+				collection.drop();
+				return null;
+			}
+		}, collectionName);
 	}
 
 
@@ -287,21 +357,24 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#insertList(java.util.List)
 	 */
-	public void insertList(List<Object> listToSave) {
+	public void insertList(List<? extends Object> listToSave) {
 		insertList(getRequiredDefaultCollectionName(), listToSave);
 	}
 
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#insertList(java.lang.String, java.util.List)
 	 */
-	public void insertList(String collectionName, List<Object> listToSave) {
+	public void insertList(String collectionName, List<? extends Object> listToSave) {
 		insertList(collectionName, listToSave, this.mongoConverter);
 	}
 
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#insertList(java.lang.String, java.util.List, org.springframework.data.document.mongodb.MongoWriter)
 	 */
-	public <T> void insertList(String collectionName, List<T> listToSave, MongoWriter<T> writer) {
+	public <T> void insertList(String collectionName, List<? extends T> listToSave, MongoWriter<T> writer) {
+		
+		Assert.notNull(writer);
+		
 		List<DBObject> dbObjectList = new ArrayList<DBObject>();
 		for (T o : listToSave) {
 			BasicDBObject dbDoc = new BasicDBObject();
@@ -341,51 +414,56 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 	}
 
 
-	protected Object insertDBObject(String collectionName, DBObject dbDoc) {
+	protected Object insertDBObject(String collectionName, final DBObject dbDoc) {
-		if (dbDoc.keySet().size() > 0 ) {
+
-			WriteResult wr = null;
+		if (dbDoc.keySet().isEmpty()) {
-			try {
-				wr = getDb().getCollection(collectionName).insert(dbDoc);
-				return dbDoc.get(ID);
-			} catch (MongoException e) {
-				throw new DataRetrievalFailureException(wr.getLastError().getErrorMessage(), e);
-			}
-		}
-		else {
 			return null;
 		}
+		
+		return execute(new CollectionCallback<Object>() {
+			public Object doInCollection(DBCollection collection) throws MongoException, DataAccessException {
+				collection.insert(dbDoc);
+				return dbDoc.get(ID);
+			}
+		}, collectionName);
 	}
 	
-	protected List<Object> insertDBObjectList(String collectionName, List<DBObject> dbDocList) {
+	
-		if (!dbDocList.isEmpty()) {
+	
+
+	protected List<Object> insertDBObjectList(String collectionName, final List<DBObject> dbDocList) {
+		
+		if (dbDocList.isEmpty()) {
+			return Collections.emptyList();
+		}
+
+		execute(new CollectionCallback<Void>() {
+			public Void doInCollection(DBCollection collection) throws MongoException, DataAccessException {
+				collection.insert(dbDocList);
+				return null;
+			}
+		}, collectionName);
+
 		List<Object> ids = new ArrayList<Object>();
-			WriteResult wr = null;
-			try {
-				wr = getDb().getCollection(collectionName).insert(dbDocList);
 		for (DBObject dbo : dbDocList) {
 			ids.add(dbo.get(ID));
 		}
 		return ids;
-			} catch (MongoException e) {
-				throw new DataRetrievalFailureException(wr.getLastError().getErrorMessage(), e);
-			}
-		} else {
-			return null;
-		}
 	}
 
-	protected Object saveDBObject(String collectionName, DBObject dbDoc) {
+	protected Object saveDBObject(String collectionName, final DBObject dbDoc) {
-		if (dbDoc.keySet().size() > 0 ) {
+		
-			WriteResult wr = null;
+		if (dbDoc.keySet().isEmpty()) {
-			try {
-				wr = getDb().getCollection(collectionName).save(dbDoc);
-				return dbDoc.get(ID);
-			} catch (MongoException e) {
-				throw new DataRetrievalFailureException(wr.getLastError().getErrorMessage(), e);
-			}
-		} else {
 			return null;
 		}
+		
+		return execute(new CollectionCallback<Object>() {
+
+			public Object doInCollection(DBCollection collection) throws MongoException, DataAccessException {
+				collection.save(dbDoc);
+				return dbDoc.get(ID);
+			}
+		}, collectionName);
 	}
 
 	/* (non-Javadoc)
@@ -398,13 +476,13 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#updateFirst(java.lang.String, com.mongodb.DBObject, com.mongodb.DBObject)
 	 */
-	public void updateFirst(String collectionName, DBObject queryDoc, DBObject updateDoc) {
+	public void updateFirst(String collectionName, final DBObject queryDoc, final DBObject updateDoc) {
-
+		execute(new CollectionCallback<Void>() {
-		try {
+			public Void doInCollection(DBCollection collection) throws MongoException, DataAccessException {
-			getDb().getCollection(collectionName).update(queryDoc, updateDoc);
+				collection.update(queryDoc, updateDoc);
-		} catch (MongoException e) {
+				return null;
-			throw new DataRetrievalFailureException("Error during update using " + queryDoc + ", " + updateDoc + "!", e);
 			}
+		}, collectionName);
 	}
 	
 	/* (non-Javadoc)
@@ -417,12 +495,13 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#updateMulti(java.lang.String, com.mongodb.DBObject, com.mongodb.DBObject)
 	 */
-	public void updateMulti(String collectionName, DBObject queryDoc, DBObject updateDoc) {
+	public void updateMulti(String collectionName, final DBObject queryDoc, final DBObject updateDoc) {
-		try {
+		execute(new CollectionCallback<Void>() {
-			getDb().getCollection(collectionName).updateMulti(queryDoc, updateDoc);
+			public Void doInCollection(DBCollection collection) throws MongoException, DataAccessException {
-		} catch (MongoException e) {
+				collection.updateMulti(queryDoc, updateDoc);
-			throw new DataRetrievalFailureException("Error during updateMulti using " + queryDoc + ", " + updateDoc + "!", e);
+				return null;
 			}
+		}, collectionName);
 	}
 	
 	/* (non-Javadoc)
@@ -435,12 +514,13 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#remove(java.lang.String, com.mongodb.DBObject)
 	 */
-	public void remove(String collectionName, DBObject queryDoc) {
+	public void remove(String collectionName, final DBObject queryDoc) {
-		try {
+		execute(new CollectionCallback<Void>() {
-			getDb().getCollection(collectionName).remove(queryDoc);
+			public Void doInCollection(DBCollection collection) throws MongoException, DataAccessException {
-		} catch (MongoException e) {
+				collection.remove(queryDoc);
-			throw new DataRetrievalFailureException("Error during remove using "  + queryDoc + "!", e);
+				return null;
 			}
+		}, collectionName);
 	}
 	
 
@@ -448,53 +528,35 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 	 * @see org.springframework.data.document.mongodb.MongoOperations#getCollection(java.lang.Class)
 	 */
 	public <T> List<T> getCollection(Class<T> targetClass) {
-		
+		return executeEach(new FindCallback(null), null, new ReadDbObjectCallback<T>(mongoConverter, targetClass),
-		List<T> results = new ArrayList<T>();
+				getDefaultCollectionName());
-		DBCollection collection = getDb().getCollection(getDefaultCollectionName());
-		for (DBObject dbo : collection.find()) {
-			Object obj = mongoConverter.read(targetClass, dbo);
-			//effectively acts as a query on the collection restricting it to elements of a specific type
-			if (targetClass.isInstance(obj)) {
-				results.add(targetClass.cast(obj));
-			}
-		}
-		return results;
 	}
 	
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#getCollection(java.lang.String, java.lang.Class)
 	 */
 	public <T> List<T> getCollection(String collectionName, Class<T> targetClass) {
-		
+		return executeEach(new FindCallback(null), null, new ReadDbObjectCallback<T>(mongoConverter, targetClass),
-		List<T> results = new ArrayList<T>();
+				collectionName);
-		DBCollection collection = getDb().getCollection(collectionName);
-		for (DBObject dbo : collection.find()) {
-			Object obj = mongoConverter.read(targetClass, dbo);
-			//effectively acts as a query on the collection restricting it to elements of a specific type
-			if (targetClass.isInstance(obj)) {
-				results.add(targetClass.cast(obj));
-			}
-		}
-		return results;
 	}
 
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#getCollectionNames()
 	 */
-	public List<String> getCollectionNames() {
+	public Set<String> getCollectionNames() {
-		return new ArrayList<String>(getDb().getCollectionNames());
+		return execute(new DBCallback<Set<String>>() {
+			public Set<String> doInDB(DB db) throws MongoException, DataAccessException {
+				return db.getCollectionNames();
+			}
+		});
 	}
 
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#getCollection(java.lang.String, java.lang.Class, org.springframework.data.document.mongodb.MongoReader)
 	 */
 	public <T> List<T> getCollection(String collectionName, Class<T> targetClass, MongoReader<T> reader) {
-		List<T> results = new ArrayList<T>();
+		return executeEach(new FindCallback(null), null, new ReadDbObjectCallback<T>(reader, targetClass),
-		DBCollection collection = getDb().getCollection(collectionName);
+				collectionName);
-		for (DBObject dbo : collection.find()) {
-			results.add(reader.read(targetClass, dbo));
-		}
-		return results;
 	}
 	
 	// Queries that take JavaScript to express the query.
@@ -562,37 +624,18 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 	 * @see org.springframework.data.document.mongodb.MongoOperations#query(java.lang.String, com.mongodb.DBObject, java.lang.Class, org.springframework.data.document.mongodb.CursorPreparer)
 	 */
 	public <T> List<T> query(String collectionName, DBObject query, Class<T> targetClass, CursorPreparer preparer) {
-		DBCollection collection = getDb().getCollection(collectionName);
+		return executeEach(new FindCallback(query), preparer, new ReadDbObjectCallback<T>(mongoConverter, targetClass),
-		List<T> results = new ArrayList<T>();
+				collectionName);
-		DBCursor cursor = collection.find(query);
-		if (preparer != null) {
-			preparer.prepare(cursor);
-		}
-		for (DBObject dbo : cursor) {
-			Object obj = mongoConverter.read(targetClass,dbo);
-			//effectively acts as a query on the collection restricting it to elements of a specific type
-			if (targetClass.isInstance(obj)) {
-				results.add(targetClass.cast(obj));
-			}
-		}
-		return results;
 	}
 
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#query(java.lang.String, com.mongodb.DBObject, java.lang.Class, org.springframework.data.document.mongodb.MongoReader)
 	 */
 	public <T> List<T> query(String collectionName, DBObject query, Class<T> targetClass, MongoReader<T> reader) {
-		DBCollection collection = getDb().getCollection(collectionName);
+		return executeEach(new FindCallback(query), null, new ReadDbObjectCallback<T>(reader, targetClass),
-		List<T> results = new ArrayList<T>();
+				collectionName);
-		for (DBObject dbo : collection.find(query)) {
-			results.add(reader.read(targetClass, dbo));
-		}
-		return results;
 	}
 
-	public RuntimeException convertMongoAccessException(RuntimeException ex) {
-		return MongoDbUtils.translateMongoExceptionIfPossible(ex);
-	}
 
 	public DB getDb() {
 		return MongoDbUtils.getDB(mongo, databaseName, username, password == null ? null : password.toCharArray());
@@ -635,16 +678,81 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 		}
 	}
 	
+	/**
+	 * Tries to convert the given {@link RuntimeException} into a {@link DataAccessException} but returns the original
+	 * exception if the conversation failed. Thus allows safe rethrowing of the return value.
+	 * 
+	 * @param ex
+	 * @return
+	 */
+	private RuntimeException potentiallyConvertRuntimeException(RuntimeException ex) {
+
+		RuntimeException resolved = this.exceptionTranslator.translateExceptionIfPossible(ex);
+    	return resolved == null ? ex : resolved;
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
 	 */
 	public void afterPropertiesSet() {
 		if (this.getDefaultCollectionName() != null) {
-			DB db = getDb();
+			if (!collectionExists(getDefaultCollectionName())) {
-			if (! db.collectionExists(getDefaultCollectionName())) {
+				createCollection(getDefaultCollectionName(), null);
-				db.createCollection(getDefaultCollectionName(), null);
 			}
 		}
 	}
+	
+	
+	/**
+	 * Simple {@link CollectionCallback} that takes a query {@link DBObject} and executes that against the
+	 * {@link DBCollection}.
+	 * 
+	 * @author Oliver Gierke
+	 */
+	private static class FindCallback implements CollectionCallback<DBCursor> {
+		
+		private final DBObject query;
+		
+		public FindCallback(DBObject query) {
+			this.query = query;
+		}
+
+		public DBCursor doInCollection(DBCollection collection) throws MongoException, DataAccessException {
+			return collection.find(query);
+		}
+	}
+	
+	/**
+	 * Simple internal callback to allow operations on a {@link DBObject}.
+	 *
+	 * @author Oliver Gierke
+	 */
+	
+	private interface DbObjectCallback<T> {
+		
+		T doWith(DBObject object);
+	}
+	
+	/**
+	 * Simple {@link DbObjectCallback} that will transform {@link DBObject} into the given target type using the given
+	 * {@link MongoReader}.
+	 * 
+	 * @author Oliver Gierke
+	 */
+	private static class ReadDbObjectCallback<T> implements DbObjectCallback<T> {
+		
+		private final MongoReader<? super T> reader;
+		private final Class<T> type;
+		
+		public ReadDbObjectCallback(MongoReader<? super T> reader, Class<T> type) {
+			this.reader = reader;
+			this.type = type;
+		}
+		
+		@SuppressWarnings("unchecked")
+		public T doWith(DBObject object) {
+			return (T) reader.read(type, object);
+		}
+	}
 }

spring-data-mongodb/src/test/java/org/springframework/data/document/mongodb/MongoOperationsUnitTests.java

@@ -0,0 +1,344 @@
+/*
+ * Copyright 2011 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.springframework.data.document.mongodb;
+
+import static org.junit.Assert.*;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
+import org.springframework.dao.DataAccessException;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.DBObject;
+
+/**
+ * Abstract base class for unit tests to specify behaviour we expect from {@link MongoOperations}. Subclasses return
+ * instances of their implementation and thus can see if it correctly implements the {@link MongoOperations} interface.
+ * 
+ * @author Oliver Gierke
+ */
+@RunWith(MockitoJUnitRunner.class)
+public abstract class MongoOperationsUnitTests {
+	
+	@Mock
+	CollectionCallback<Object> collectionCallback;
+	@Mock
+	DbCallback<Object> dbCallback;
+	
+	MongoConverter converter;
+	Person person;
+	List<Person> persons;
+	
+	@Before
+	public final void operationsSetUp() {
+		
+		person = new Person("Oliver");
+		persons = Arrays.asList(person);
+		
+		converter = new MongoConverter() {
+			
+			public Object read(Class<? extends Object> clazz, DBObject dbo) {
+				return person;
+			}
+			
+			public void write(Object t, DBObject dbo) {
+				dbo.put("firstName", person.getFirstName());
+			}
+		};
+	}
+	
+	
+	@Test(expected = IllegalArgumentException.class)
+	@SuppressWarnings({"unchecked", "rawtypes"})
+	public void rejectsNullForCollectionCallback() {
+		
+		getOperations().execute((CollectionCallback) null);
+	}
+	
+	@Test(expected = IllegalArgumentException.class)
+	@SuppressWarnings({"unchecked", "rawtypes"})
+	public void rejectsNullForCollectionCallback2() {
+		getOperations().execute((CollectionCallback) null, "collection");
+	}
+	
+	@Test(expected = IllegalArgumentException.class)
+	@SuppressWarnings({"unchecked", "rawtypes"})
+	public void rejectsNullForDbCallback() {
+		getOperations().execute((DbCallback) null);
+	}
+
+	@Test
+	public void convertsExceptionForCollectionExists() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.collectionExists("foo");
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForCreateCollection() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.createCollection("foo");
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForCreateCollection2() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.createCollection("foo", new CollectionOptions(1, 1, true));
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForDropCollection() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.dropCollection("foo");
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForExecuteCollectionCallback() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.execute(collectionCallback);
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForExecuteDbCallback() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.execute(dbCallback);
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForExecuteCollectionCallbackAndCollection() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.execute(collectionCallback, "collection");
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForExecuteCommand() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.executeCommand(new BasicDBObject());
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForExecuteStringCommand() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.executeCommand("");
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForExecuteInSession() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.executeInSession(dbCallback);
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForGetCollection() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.getCollection(Object.class);
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForGetCollectionWithCollectionName() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.getCollection("collection");
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForGetCollectionWithCollectionNameAndType() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.getCollection("collection", Object.class);
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForGetCollectionWithCollectionNameTypeAndReader() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.getCollection("collection", Object.class, converter);
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForGetCollectionNames() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.getCollectionNames();
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForGetDefaultCollection() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.getDefaultCollection();
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForInsert() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.insert(person);
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForInsert2() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.insert("collection", person);
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForInsert3() {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.insert("collection", person, converter);
+			}
+		}.assertDataAccessException();
+	}
+	
+	
+	@Test
+	public void convertsExceptionForInsertList() throws Exception {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.insertList(persons);
+			}
+		}.assertDataAccessException();
+	}
+	
+	@Test
+	public void convertsExceptionForGetInsertList2() throws Exception {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.insertList("collection", persons);
+			}
+		}.assertDataAccessException();
+	}
+
+	@Test
+	public void convertsExceptionForGetInsertList3() throws Exception {
+		new Execution() {
+			@Override
+			public void doWith(MongoOperations operations) {
+				operations.insertList("collection", persons, converter);
+			}
+		}.assertDataAccessException();
+	}
+	
+	private abstract class Execution {
+
+		public void assertDataAccessException() {
+			assertException(DataAccessException.class);
+		}
+
+		public void assertException(Class<? extends Exception> exception) {
+
+			try {
+				doWith(getOperationsForExceptionHandling());
+				fail("Expected " + exception + " but completed without any!");
+			} catch (Exception e) {
+				assertTrue("Expected " + exception + " but got " + e, exception.isInstance(e));
+			}
+		}
+
+		public abstract void doWith(MongoOperations operations);
+	}
+
+	/**
+	 * Expects an {@link MongoOperations} instance that will be used to check that invoking methods on it will only
+	 * cause {@link DataAccessException}s.
+	 * 
+	 * @return
+	 */
+	protected abstract MongoOperations getOperationsForExceptionHandling();
+	
+	/**
+	 * Returns a plain {@link MongoOperations}.
+	 * 
+	 * @return
+	 */
+	protected abstract MongoOperations getOperations();
+}

spring-data-mongodb/src/test/java/org/springframework/data/document/mongodb/MongoTemplateUnitTests.java

@@ -23,7 +23,7 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.runners.MockitoJUnitRunner;
-import org.springframework.dao.DataRetrievalFailureException;
+import org.springframework.dao.DataAccessException;
 import org.springframework.test.util.ReflectionTestUtils;
 
 import com.mongodb.DB;
@@ -36,7 +36,7 @@ import com.mongodb.MongoException;
  * @author Oliver Gierke
  */
 @RunWith(MockitoJUnitRunner.class)
-public class MongoTemplateUnitTests {
+public class MongoTemplateUnitTests extends MongoOperationsUnitTests {
 
 	MongoTemplate template;
 
@@ -48,7 +48,7 @@ public class MongoTemplateUnitTests {
 
 	@Before
 	public void setUp() {
-		this.template = new MongoTemplate(mongo, "database");
+		this.template = new MongoTemplate(mongo, "database", "default");
 	}
 
 	@Test(expected = IllegalArgumentException.class)
@@ -61,7 +61,7 @@ public class MongoTemplateUnitTests {
 		new MongoTemplate(null, "database");
 	}
 
-	@Test(expected = DataRetrievalFailureException.class)
+	@Test(expected = DataAccessException.class)
 	public void removeHandlesMongoExceptionProperly() throws Exception {
 		MongoTemplate template = mockOutGetDb();
 		when(db.getCollection("collection")).thenThrow(new MongoException("Exception!"));
@@ -87,4 +87,22 @@ public class MongoTemplateUnitTests {
 		stub(template.getDb()).toReturn(db);
 		return template;
 	}
+
+	/* (non-Javadoc)
+	 * @see org.springframework.data.document.mongodb.MongoOperationsUnitTests#getOperations()
+	 */
+	@Override
+	protected MongoOperations getOperationsForExceptionHandling() {
+		MongoTemplate template = spy(this.template);
+		stub(template.getDb()).toThrow(new MongoException("Error!"));
+		return template;
+	}
+	
+	/* (non-Javadoc)
+	 * @see org.springframework.data.document.mongodb.MongoOperationsUnitTests#getOperations()
+	 */
+	@Override
+	protected MongoOperations getOperations() {
+		return this.template;
+	}
 }

spring-data-mongodb/src/test/java/org/springframework/data/document/mongodb/Person.java

@@ -21,6 +21,14 @@ public class Person {
 	
 	private Person friend;
 	
+	public Person() {
+		
+	}
+	
+	public Person(String firstname) {
+		this.firstName = firstname;
+	}
+
 	
 	public String getFirstName() {
 		return firstName;