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Cayenne Object Persistence Framework
/*****************************************************************
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.cayenne;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;
import org.apache.cayenne.access.DataContext;
import org.apache.cayenne.access.DataNode;
import org.apache.cayenne.access.types.ExtendedTypeMap;
import org.apache.cayenne.conf.Configuration;
import org.apache.cayenne.map.DbAttribute;
import org.apache.cayenne.map.DbJoin;
import org.apache.cayenne.map.DbRelationship;
import org.apache.cayenne.map.EntityResolver;
import org.apache.cayenne.map.ObjAttribute;
import org.apache.cayenne.map.ObjEntity;
import org.apache.cayenne.map.ObjRelationship;
import org.apache.cayenne.property.PropertyUtils;
import org.apache.cayenne.validation.BeanValidationFailure;
import org.apache.cayenne.validation.ValidationFailure;
import org.apache.cayenne.validation.ValidationResult;
import org.apache.cayenne.xml.XMLDecoder;
import org.apache.cayenne.xml.XMLEncoder;
import org.apache.cayenne.xml.XMLSerializable;
/**
* A default implementation of DataObject interface. It is normally used as a superclass
* of Cayenne persistent objects.
*
* @author Andrei Adamchik
*/
public class CayenneDataObject implements DataObject, XMLSerializable {
protected long snapshotVersion = DEFAULT_VERSION;
protected ObjectId objectId;
protected transient int persistenceState = PersistenceState.TRANSIENT;
protected transient ObjectContext objectContext;
protected Map values = new HashMap();
/**
* Returns a DataContext that holds this object. Object becomes assocaiated with a
* DataContext either when the object is fetched using a query, or when a new object
* is registered explicitly with a DataContext.
*/
public DataContext getDataContext() {
if (objectContext == null || objectContext instanceof DataContext) {
return (DataContext) objectContext;
}
throw new CayenneRuntimeException("ObjectContext is not a DataContext: "
+ objectContext);
}
/**
* Initializes DataObject's persistence context.
*/
public void setDataContext(DataContext dataContext) {
this.objectContext = dataContext;
if (dataContext == null) {
this.persistenceState = PersistenceState.TRANSIENT;
}
}
/**
* Returns mapped ObjEntity for this object. If an object is transient or is not
* mapped returns null.
*
* @since 1.2
*/
public ObjEntity getObjEntity() {
return (getObjectContext() != null) ? getObjectContext()
.getEntityResolver()
.lookupObjEntity(this) : null;
}
public ObjectId getObjectId() {
return objectId;
}
public void setObjectId(ObjectId objectId) {
this.objectId = objectId;
}
public int getPersistenceState() {
return persistenceState;
}
public void setPersistenceState(int persistenceState) {
this.persistenceState = persistenceState;
if (persistenceState == PersistenceState.HOLLOW) {
values.clear();
}
}
public Object readNestedProperty(String path) {
Object object = null;
CayenneDataObject dataObject = this;
String[] tokenized = tokenizePath(path);
int length = tokenized.length;
int pathIndex = 0;
for (int i = 0; i < length; i++) {
pathIndex += tokenized[i].length() + 1;
object = dataObject.readSimpleProperty(tokenized[i]);
if (object == null) {
return null;
}
else if (object instanceof CayenneDataObject) {
dataObject = (CayenneDataObject) object;
}
else if (i + 1 < length) {
// read the rest of the path via introspection
return PropertyUtils.getProperty(object, path.substring(pathIndex));
}
}
return object;
}
private static final String[] tokenizePath(String path) {
if (path == null) {
throw new NullPointerException("Null property path.");
}
if (path.length() == 0) {
throw new IllegalArgumentException("Empty property path.");
}
// take a shortcut for simple properties
if (path.indexOf(".") < 0) {
return new String[] {
path
};
}
StringTokenizer tokens = new StringTokenizer(path, ".");
int length = tokens.countTokens();
String[] tokenized = new String[length];
for (int i = 0; i < length; i++) {
tokenized[i] = tokens.nextToken();
}
return tokenized;
}
private final Object readSimpleProperty(String property) {
// side effect - resolves HOLLOW object
Object object = readProperty(property);
// if a null value is returned, there is still a chance to
// find a non-persistent property via reflection
if (object == null && !values.containsKey(property)) {
object = PropertyUtils.getProperty(this, property);
}
return object;
}
/**
* @since 1.1
* @deprecated since 1.2 use 'getObjectContext().prepareForAccess(object)'
*/
public void resolveFault() {
if (objectContext != null) {
objectContext.prepareForAccess(this, null);
}
}
public Object readProperty(String propName) {
if (objectContext != null) {
objectContext.prepareForAccess(this, propName);
}
Object object = readPropertyDirectly(propName);
// must resolve faults immediately
if (object instanceof Fault) {
object = ((Fault) object).resolveFault(this, propName);
writePropertyDirectly(propName, object);
}
return object;
}
public Object readPropertyDirectly(String propName) {
return values.get(propName);
}
public void writeProperty(String propName, Object val) {
if (objectContext != null) {
objectContext.prepareForAccess(this, propName);
// note how we notify DataContext of change BEFORE the object is actually
// changed... this is needed to take a valid current snapshot
Object oldValue = readPropertyDirectly(propName);
objectContext.propertyChanged(this, propName, oldValue, val);
}
writePropertyDirectly(propName, val);
}
public void writePropertyDirectly(String propName, Object val) {
values.put(propName, val);
}
public void removeToManyTarget(String relName, DataObject value, boolean setReverse) {
// Now do the rest of the normal handling (regardless of whether it was
// flattened or not)
List relList = (List) readProperty(relName);
// call 'recordArcDeleted' AFTER readProperty as readProperty ensures that this
// object fault is resolved
getDataContext().getObjectStore().recordArcDeleted(
this,
value != null ? value.getObjectId() : null,
relName);
relList.remove(value);
if (persistenceState == PersistenceState.COMMITTED) {
persistenceState = PersistenceState.MODIFIED;
}
if (value != null && setReverse) {
unsetReverseRelationship(relName, value);
}
}
public void addToManyTarget(String relName, DataObject value, boolean setReverse) {
if (value == null) {
throw new NullPointerException("Attempt to add null target DataObject.");
}
willConnect(relName, value);
// Now do the rest of the normal handling (regardless of whether it was
// flattened or not)
List list = (List) readProperty(relName);
// call 'recordArcCreated' AFTER readProperty as readProperty ensures that this
// object fault is resolved
getDataContext().getObjectStore().recordArcCreated(
this,
value.getObjectId(),
relName);
list.add(value);
if (value != null && setReverse) {
setReverseRelationship(relName, value);
}
}
public void setToOneTarget(
String relationshipName,
DataObject value,
boolean setReverse) {
willConnect(relationshipName, value);
Object oldTarget = readProperty(relationshipName);
if (oldTarget == value) {
return;
}
getDataContext().getObjectStore().recordArcCreated(
this,
value != null ? value.getObjectId() : null,
relationshipName);
if (setReverse) {
// unset old reverse relationship
if (oldTarget instanceof DataObject) {
unsetReverseRelationship(relationshipName, (DataObject) oldTarget);
}
// set new reverse relationship
if (value != null) {
setReverseRelationship(relationshipName, value);
}
}
objectContext.prepareForAccess(this, relationshipName);
writePropertyDirectly(relationshipName, value);
}
/**
* Called before establishing a relationship with another object. Applies "persistence
* by reachability" logic, pulling one of the two objects to a DataConext of another
* object in case one of the objects is transient. If both objects are persistent, and
* they don't have the same DataContext, CayenneRuntimeException is thrown.
*
* @since 1.2
*/
protected void willConnect(String relationshipName, DataObject dataObject) {
// first handle most common case - both objects are in the same
// DataContext or target is null
if (dataObject == null
|| this.getObjectContext() == dataObject.getObjectContext()) {
return;
}
else if (this.getObjectContext() == null && dataObject.getObjectContext() != null) {
dataObject.getDataContext().registerNewObject(this);
}
else if (this.getObjectContext() != null && dataObject.getObjectContext() == null) {
this.getDataContext().registerNewObject(dataObject);
}
else {
throw new CayenneRuntimeException(
"Cannot set object as destination of relationship "
+ relationshipName
+ " because it is in a different DataContext");
}
}
/**
* Initializes reverse relationship from object val to this object.
*
* @param relName name of relationship from this object to val.
*/
protected void setReverseRelationship(String relName, DataObject val) {
ObjRelationship rel = (ObjRelationship) objectContext
.getEntityResolver()
.lookupObjEntity(objectId.getEntityName())
.getRelationship(relName);
ObjRelationship revRel = rel.getReverseRelationship();
if (revRel != null) {
if (revRel.isToMany())
val.addToManyTarget(revRel.getName(), this, false);
else
val.setToOneTarget(revRel.getName(), this, false);
}
}
/**
* Removes current object from reverse relationship of object val to
* this object.
*/
protected void unsetReverseRelationship(String relName, DataObject val) {
EntityResolver resolver = objectContext.getEntityResolver();
ObjEntity entity = resolver.lookupObjEntity(objectId.getEntityName());
if (entity == null) {
throw new IllegalStateException("DataObject's entity is unmapped, objectId: "
+ objectId);
}
ObjRelationship rel = (ObjRelationship) entity.getRelationship(relName);
ObjRelationship revRel = rel.getReverseRelationship();
if (revRel != null) {
if (revRel.isToMany())
val.removeToManyTarget(revRel.getName(), this, false);
else
val.setToOneTarget(revRel.getName(), null, false);
}
}
/**
* A variation of "toString" method, that may be more efficient in some cases. For
* example when printing a list of objects into the same String.
*/
public StringBuffer toStringBuffer(StringBuffer buffer, boolean fullDesc) {
String id = (objectId != null) ? objectId.toString() : "";
String state = PersistenceState.persistenceStateName(persistenceState);
buffer.append('{').append(id).append("; ").append(state).append("; ");
if (fullDesc) {
appendProperties(buffer);
}
buffer.append("}");
return buffer;
}
protected void appendProperties(StringBuffer buffer) {
buffer.append("[");
Iterator it = values.entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
buffer.append(entry.getKey()).append("=>");
Object value = entry.getValue();
if (value instanceof Persistent) {
buffer.append('{').append(((Persistent) value).getObjectId()).append('}');
}
else if (value instanceof Collection) {
buffer.append("(..)");
}
else if (value instanceof Fault) {
buffer.append('?');
}
else {
buffer.append(value);
}
if (it.hasNext()) {
buffer.append("; ");
}
}
buffer.append("]");
}
public String toString() {
return toStringBuffer(new StringBuffer(), true).toString();
}
/**
* Default implementation does nothing.
*
* @see org.apache.cayenne.DataObject#fetchFinished()
*/
public void fetchFinished() {
}
private void writeObject(ObjectOutputStream out) throws IOException {
out.writeInt(persistenceState);
switch (persistenceState) {
// New, modified or transient or deleted - write the whole shebang
// The other states (committed, hollow) all need just ObjectId
case PersistenceState.TRANSIENT:
case PersistenceState.NEW:
case PersistenceState.MODIFIED:
case PersistenceState.DELETED:
out.writeObject(values);
break;
}
out.writeObject(objectId);
}
private void readObject(ObjectInputStream in) throws IOException,
ClassNotFoundException {
this.persistenceState = in.readInt();
switch (persistenceState) {
case PersistenceState.TRANSIENT:
case PersistenceState.NEW:
case PersistenceState.MODIFIED:
case PersistenceState.DELETED:
values = (Map) in.readObject();
break;
case PersistenceState.COMMITTED:
case PersistenceState.HOLLOW:
this.persistenceState = PersistenceState.HOLLOW;
// props will be populated when required (readProperty called)
values = new HashMap();
break;
}
this.objectId = (ObjectId) in.readObject();
// DataContext will be set *IF* the DataContext it came from is also
// deserialized. Setting of DataContext is handled by the DataContext
// itself
}
/**
* Returns a version of a DataRow snapshot that was used to create this object.
*
* @since 1.1
*/
public long getSnapshotVersion() {
return snapshotVersion;
}
/**
* @since 1.1
*/
public void setSnapshotVersion(long snapshotVersion) {
this.snapshotVersion = snapshotVersion;
}
/**
* Performs property validation of the object, appending any validation failures to
* the provided validationResult object. This method is invoked from "validateFor.."
* before committing a NEW or MODIFIED object to the database. Validation includes
* checking for null values and value sizes. CayenneDataObject subclasses may override
* this method, calling super.
*
* @since 1.1
*/
protected void validateForSave(ValidationResult validationResult) {
ObjEntity objEntity = getDataContext().getEntityResolver().lookupObjEntity(this);
if (objEntity == null) {
throw new CayenneRuntimeException(
"No ObjEntity mapping found for DataObject " + getClass().getName());
}
DataNode node = getDataContext().getParentDataDomain().lookupDataNode(
objEntity.getDataMap());
if (node == null) {
throw new CayenneRuntimeException("No DataNode found for objEntity: "
+ objEntity.getName());
}
ExtendedTypeMap types = node.getAdapter().getExtendedTypes();
// validate mandatory attributes
// handling a special case - meaningful mandatory FK... defer failures until
// relationship validation is done... This is just a temporary solution, as
// handling meaningful keys within the object lifecycle requires something more,
// namely read/write methods for relationships and direct values should be
// synchronous with each other..
Map failedDbAttributes = null;
Iterator attributes = objEntity.getAttributes().iterator();
while (attributes.hasNext()) {
ObjAttribute objAttribute = (ObjAttribute) attributes.next();
DbAttribute dbAttribute = objAttribute.getDbAttribute();
Object value = this.readPropertyDirectly(objAttribute.getName());
if (dbAttribute.isMandatory()) {
ValidationFailure failure = BeanValidationFailure.validateNotNull(
this,
objAttribute.getName(),
value);
if (failure != null) {
if (failedDbAttributes == null) {
failedDbAttributes = new HashMap();
}
failedDbAttributes.put(dbAttribute.getName(), failure);
continue;
}
}
if (value != null) {
// TODO: should we pass null values for validation as well?
// if so, class can be obtained from ObjAttribute...
types.getRegisteredType(value.getClass()).validateProperty(
this,
objAttribute.getName(),
value,
dbAttribute,
validationResult);
}
}
// validate mandatory relationships
Iterator relationships = objEntity.getRelationships().iterator();
while (relationships.hasNext()) {
ObjRelationship relationship = (ObjRelationship) relationships.next();
if (relationship.isSourceIndependentFromTargetChange()) {
continue;
}
List dbRels = relationship.getDbRelationships();
if (dbRels.isEmpty()) {
// Wha?
continue;
}
// if db relationship is not based on a PK and is based on mandatory
// attributes, see if we have a target object set
boolean validate = true;
DbRelationship dbRelationship = (DbRelationship) dbRels.get(0);
Iterator joins = dbRelationship.getJoins().iterator();
while (joins.hasNext()) {
DbJoin join = (DbJoin) joins.next();
DbAttribute source = join.getSource();
if (source.isMandatory()) {
// clear attribute failures...
if (failedDbAttributes != null && !failedDbAttributes.isEmpty()) {
failedDbAttributes.remove(source.getName());
// loop through all joins if there were previous mandatory
// attribute failures....
if (!failedDbAttributes.isEmpty()) {
continue;
}
}
}
else {
// do not validate if the relation is based on
// multiple keys with some that can be nullable.
validate = false;
}
}
if (validate) {
Object value = this.readPropertyDirectly(relationship.getName());
ValidationFailure failure = BeanValidationFailure.validateNotNull(
this,
relationship.getName(),
value);
if (failure != null) {
validationResult.addFailure(failure);
continue;
}
}
}
// deal with previously found attribute failures...
if (failedDbAttributes != null && !failedDbAttributes.isEmpty()) {
Iterator failedAttributes = failedDbAttributes.values().iterator();
while (failedAttributes.hasNext()) {
validationResult.addFailure((ValidationFailure) failedAttributes.next());
}
}
}
/**
* Calls {@link #validateForSave(ValidationResult)}. CayenneDataObject subclasses may
* override it providing validation logic that should be executed for the newly
* created objects before saving them.
*
* @since 1.1
*/
public void validateForInsert(ValidationResult validationResult) {
validateForSave(validationResult);
}
/**
* Calls {@link #validateForSave(ValidationResult)}. CayenneDataObject subclasses may
* override it providing validation logic that should be executed for the modified
* objects before saving them.
*
* @since 1.1
*/
public void validateForUpdate(ValidationResult validationResult) {
validateForSave(validationResult);
}
/**
* This implementation does nothing. CayenneDataObject subclasses may override it
* providing validation logic that should be executed for the deleted objects before
* committing them.
*
* @since 1.1
*/
public void validateForDelete(ValidationResult validationResult) {
// does nothing
}
/**
* Encodes object to XML using provided encoder.
*
* @since 1.2
*/
public void encodeAsXML(XMLEncoder encoder) {
EntityResolver er = getDataContext().getEntityResolver();
ObjEntity object = er.lookupObjEntity(getClass());
String[] fields = this.getClass().getName().split("\\.");
encoder.setRoot(fields[fields.length - 1], this.getClass().getName());
for (Iterator it = object.getDeclaredAttributes().iterator(); it.hasNext();) {
ObjAttribute att = (ObjAttribute) it.next();
String name = att.getName();
encoder.encodeProperty(name, readNestedProperty(name));
}
}
public void decodeFromXML(XMLDecoder decoder) {
ObjEntity object = null;
// TODO: relying on singleton Configuration is a bad idea...
// Probably decoder itself can optionally store a DataContext or an EntityResolver
// to provide "context" appropriate for a given environment
for (Iterator it = Configuration
.getSharedConfiguration()
.getDomain()
.getDataNodes()
.iterator(); it.hasNext();) {
DataNode dn = (DataNode) it.next();
EntityResolver er = dn.getEntityResolver();
object = er.lookupObjEntity(getClass());
if (null != object) {
break;
}
}
for (Iterator it = object.getDeclaredAttributes().iterator(); it.hasNext();) {
ObjAttribute att = (ObjAttribute) it.next();
String name = att.getName();
writeProperty(name, decoder.decodeObject(name));
}
}
/**
* Returns this object's DataContext.
*
* @since 1.2
*/
public ObjectContext getObjectContext() {
return objectContext;
}
/**
* @since 1.2
*/
public void setObjectContext(ObjectContext objectContext) {
this.objectContext = objectContext;
if (objectContext == null) {
this.persistenceState = PersistenceState.TRANSIENT;
}
}
}
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