/*******************************************************************************
* Copyright (c) 1998, 2008 Oracle. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.internal.queries;
import java.util.*;
import org.eclipse.persistence.internal.helper.*;
import org.eclipse.persistence.exceptions.*;
import org.eclipse.persistence.mappings.converters.*;
import org.eclipse.persistence.internal.sessions.AbstractRecord;
import org.eclipse.persistence.internal.sessions.UnitOfWorkImpl;
import org.eclipse.persistence.internal.sessions.AbstractSession;
/**
* <p><b>Purpose</b>: A MapContainerPolicy is ContainerPolicy whose container class
* implements the Map interface.
* <p>
* <p><b>Responsibilities</b>:
* Provide the functionality to operate on an instance of a Map.
*
* @see ContainerPolicy
* @see CollectionContainerPolicy
*/
public class DirectMapContainerPolicy extends InterfaceContainerPolicy {
protected DatabaseField keyField;
protected DatabaseField valueField;
protected Converter keyConverter;
protected Converter valueConverter;
/**
* INTERNAL:
* Construct a new policy.
*/
public DirectMapContainerPolicy() {
super();
}
/**
* INTERNAL:
* Construct a new policy for the specified class.
*/
public DirectMapContainerPolicy(Class containerClass) {
super(containerClass);
}
/**
* INTERNAL:
* Add key, value pair into container which implements the Map interface.
*/
public boolean addInto(Object key, Object value, Object container, AbstractSession session) {
try {
((Map)container).put(key, value);
} catch (ClassCastException ex1) {
throw QueryException.cannotAddElement(key, container, ex1);
}
return true;
}
/**
* INTERNAL:
* Add element into container which implements the Map interface. Not used since key is not obtained from the object
*/
public boolean addInto(Object element, Object container, AbstractSession session) {
throw ValidationException.operationNotSupported("addInto(Object element, Object container, Session session)");
}
/**
* INTERNAL:
* Return a container populated with the contents of the specified Vector.
*/
public Object buildContainerFromVector(Vector vector, AbstractSession session) {
Map container = (Map)containerInstance(vector.size());
AbstractRecord row;
for (Enumeration e = vector.elements(); e.hasMoreElements();) {
row = (AbstractRecord)e.nextElement();
Object key = row.get(keyField);
Object value = row.get(valueField);
if (getKeyConverter() != null) {
key = getKeyConverter().convertDataValueToObjectValue(key, session);
}
if (getValueConverter() != null) {
value = getValueConverter().convertDataValueToObjectValue(value, session);
}
if (key != null) {
container.put(key, value);
}
}
return container;
}
/**
* INTERNAL:
* Remove all the elements from container.
*/
public void clear(Object container) {
try {
((Map)container).clear();
} catch (UnsupportedOperationException ex) {
throw QueryException.methodNotValid(container, "clear()");
}
}
/**
* INTERNAL:
* Return true if keys are the same. False otherwise
*/
public boolean compareContainers(Object firstObjectMap, Object secondObjectMap) {
if (sizeFor(firstObjectMap) != sizeFor(secondObjectMap)) {
return false;
}
for (Object firstIterator = iteratorFor(firstObjectMap); hasNext(firstIterator);) {
Object key = next(firstIterator);
if (!((Map)firstObjectMap).get(key).equals(((Map)secondObjectMap).get(key))) {
return false;
}
}
return true;
}
/**
* INTERNAL:
* Return true if keys are the same in the source as the backup.
* Always true if read-only.
*/
public boolean compareKeys(Object sourceValue, AbstractSession session) {
if (((UnitOfWorkImpl)session).isClassReadOnly(sourceValue.getClass())) {
return true;
}
Object backUpVersion = ((UnitOfWorkImpl)session).getBackupClone(sourceValue, getElementDescriptor());
return (keyFrom(backUpVersion, session).equals(keyFrom(sourceValue, session)));
}
/**
* INTERNAL:
* Return the true if element exists in container.
* @return boolean true if container 'contains' element
*/
protected boolean contains(Object element, Object container) {
return ((Map)container).containsValue(element);
}
public Class getInterfaceType() {
return ClassConstants.Map_Class;
}
public boolean isDirectMapPolicy() {
return true;
}
/**
* INTERNAL:
* Return an Iterator for the given container.
*/
public Object iteratorFor(Object container) {
if (((Map)container).keySet() == null) {
return null;
}
return ((Map)container).keySet().iterator();
}
/**
* INTERNAL:
* Return an Iterator for the given container.
*/
public Object iteratorForValue(Object container) {
if (((Map)container).values() == null) {
return null;
}
return ((Map)container).values().iterator();
}
/**
* INTERNAL:
* Remove element from container which implements the Map interface.
*/
public boolean removeFrom(Object key, Object element, Object container, AbstractSession session) {
try {
Object returnValue = null;
if (key != null) {
returnValue = ((Map)container).remove(key);
} else {
returnValue = ((Map)container).remove(keyFrom(element, session));
}
if (returnValue == null) {
return false;
} else {
return true;
}
} catch (UnsupportedOperationException ex) {
throw QueryException.methodNotValid(container, "remove(Object element)");
}
}
/**
* INTERNAL:
* Remove element from container which implements the Map interface.
*/
public boolean removeFromWithIdentity(Object element, Object container, AbstractSession session) {
boolean found = false;
Vector knownKeys = new Vector(1);
try {
Iterator iterator = ((Map)container).keySet().iterator();
while (iterator.hasNext()) {
Object key = iterator.next();
if (((Map)container).get(key) == element) {
knownKeys.addElement(key);
found = true;
}
}
if (found) {
for (int index = 0; index < knownKeys.size(); ++index) {
((Map)container).remove(knownKeys.elementAt(index));
}
}
return found;
} catch (UnsupportedOperationException ex) {
throw QueryException.methodNotValid(container, "remove(Object element)");
}
}
public void setKeyField(DatabaseField field) {
keyField = field;
}
public void setValueField(DatabaseField field) {
valueField = field;
}
/**
* INTERNAL:
* Return the size of container.
*/
public int sizeFor(Object container) {
return ((Map)container).size();
}
/**
* INTERNAL:
* If the key has changed, remove the element and add it back into the target.
*/
public void validateElementAndRehashIfRequired(Object sourceValue, Object targetMap, AbstractSession session, Object targetVersionOfSource) {
if (session.isUnitOfWork()) {
//this must be a unit of work at this point
Object backupValue = ((UnitOfWorkImpl)session).getBackupClone(sourceValue, getElementDescriptor());
if (!keyFrom(backupValue, session).equals(keyFrom(sourceValue, session))) {
//the key has been changed. Remove the old value and put back the new one
removeFrom(backupValue, targetMap, session);
addInto(targetVersionOfSource, targetMap, session);
}
}
}
/**
* INTERNAL:
* Validate the container type.
*/
public boolean isValidContainer(Object container) {
// PERF: Use instanceof which is inlined, not isAssignable which is very inefficent.
return container instanceof Map;
}
/**
* INTERNAL:
* Return an value of the key from container
*/
public Object valueFromKey(Object key, Object container) {
return ((Map)container).get(key);
}
public Converter getKeyConverter() {
return keyConverter;
}
public void setKeyConverter(Converter keyConverter) {
this.keyConverter = keyConverter;
}
public void setValueConverter(Converter valueConverter) {
this.valueConverter = valueConverter;
}
public Converter getValueConverter() {
return valueConverter;
}
}