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* 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
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package org.apache.cayenne.access;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import org.apache.cayenne.ObjectId;
import org.apache.cayenne.access.DataDomainSyncBucket.PropagatedValueFactory;
import org.apache.cayenne.graph.GraphChangeHandler;
import org.apache.cayenne.graph.GraphDiff;
import org.apache.cayenne.map.Attribute;
import org.apache.cayenne.map.DbEntity;
import org.apache.cayenne.map.DbJoin;
import org.apache.cayenne.map.DbRelationship;
import org.apache.cayenne.map.ObjAttribute;
import org.apache.cayenne.map.ObjEntity;
import org.apache.cayenne.map.ObjRelationship;
/**
* Processes object diffs, generating DB diffs. Can be used for both UPDATE and INSERT.
*
* @since 1.2
* @author Andrus Adamchik
*/
class DataDomainDBDiffBuilder implements GraphChangeHandler {
private ObjEntity objEntity;
private DbEntity dbEntity;
// diff snapshot expressed in terms of object properties.
private Map currentPropertyDiff;
private Map currentArcDiff;
private Object currentId;
/**
* Resets the builder to process a new combination of objEntity/dbEntity.
*/
void reset(ObjEntity objEntity, DbEntity dbEntity) {
this.objEntity = objEntity;
this.dbEntity = dbEntity;
}
/**
* Resets the builder to process a new object for the previously set combination of
* objEntity/dbEntity.
*/
private void reset() {
currentPropertyDiff = null;
currentArcDiff = null;
currentId = null;
}
/**
* Processes GraphDiffs of a single object, converting them to DB diff.
*/
Map buildDBDiff(GraphDiff singleObjectDiff) {
reset();
singleObjectDiff.apply(this);
if (currentPropertyDiff == null && currentArcDiff == null && currentId == null) {
return null;
}
Map dbDiff = new HashMap();
appendSimpleProperties(dbDiff);
appendForeignKeys(dbDiff);
appendPrimaryKeys(dbDiff);
return dbDiff.isEmpty() ? null : dbDiff;
}
private void appendSimpleProperties(Map dbDiff) {
// populate changed columns
if (currentPropertyDiff != null) {
Iterator it = currentPropertyDiff.entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
ObjAttribute attribute = (ObjAttribute) objEntity.getAttribute(entry
.getKey()
.toString());
// this takes care of the flattened attributes, as 'getDbAttributeName'
// returns the last path component...
Attribute dbAttribute = dbEntity.getAttribute(attribute
.getDbAttributeName());
dbDiff.put(dbAttribute.getName(), entry.getValue());
}
}
}
private void appendForeignKeys(Map dbDiff) {
// populate changed FKs
if (currentArcDiff != null) {
Iterator it = currentArcDiff.entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
ObjRelationship relation = (ObjRelationship) objEntity
.getRelationship(entry.getKey().toString());
DbRelationship dbRelation = (DbRelationship) relation
.getDbRelationships()
.get(0);
ObjectId targetId = (ObjectId) entry.getValue();
Iterator joins = dbRelation.getJoins().iterator();
while (joins.hasNext()) {
DbJoin join = (DbJoin) joins.next();
Object value = (targetId != null) ? new PropagatedValueFactory(
targetId,
join.getTargetName()) : null;
dbDiff.put(join.getSourceName(), value);
}
}
}
}
private void appendPrimaryKeys(Map dbDiff) {
// populate changed PKs; note that we might end up overriding some values taken
// from the object (e.g. zero PK's).
if (currentId != null) {
dbDiff.putAll(((ObjectId) currentId).getIdSnapshot());
}
}
// ==================================================
// GraphChangeHandler methods.
// ==================================================
public void nodePropertyChanged(
Object nodeId,
String property,
Object oldValue,
Object newValue) {
// note - no checking for phantom mod... assuming there is no phantom diffs
if (currentPropertyDiff == null) {
currentPropertyDiff = new HashMap();
}
currentPropertyDiff.put(property, newValue);
}
public void arcCreated(Object nodeId, Object targetNodeId, Object arcId) {
ObjRelationship relationship = (ObjRelationship) objEntity.getRelationship(arcId
.toString());
if (!relationship.isSourceIndependentFromTargetChange()) {
if (currentArcDiff == null) {
currentArcDiff = new HashMap();
}
currentArcDiff.put(arcId, targetNodeId);
}
}
public void arcDeleted(Object nodeId, Object targetNodeId, Object arcId) {
ObjRelationship relationship = (ObjRelationship) objEntity.getRelationship(arcId
.toString());
if (!relationship.isSourceIndependentFromTargetChange()) {
if (currentArcDiff == null) {
currentArcDiff = new HashMap();
currentArcDiff.put(arcId, null);
}
// check for situation when a substitute arc was created prior to deleting the
// old arc...
else if (targetNodeId.equals(currentArcDiff.get(arcId))) {
currentArcDiff.put(arcId, null);
}
}
}
public void nodeCreated(Object nodeId) {
// need to append PK columns
this.currentId = nodeId;
}
public void nodeRemoved(Object nodeId) {
// noop
}
public void nodeIdChanged(Object nodeId, Object newId) {
// noop
}
}