oracle.toplink.essentials.internal.expressions.ManualQueryKeyExpression Maven / Gradle / Ivy
/*
* The contents of this file are subject to the terms
* of the Common Development and Distribution License
* (the "License"). You may not use this file except
* in compliance with the License.
*
* You can obtain a copy of the license at
* glassfish/bootstrap/legal/CDDLv1.0.txt or
* https://glassfish.dev.java.net/public/CDDLv1.0.html.
* See the License for the specific language governing
* permissions and limitations under the License.
*
* When distributing Covered Code, include this CDDL
* HEADER in each file and include the License file at
* glassfish/bootstrap/legal/CDDLv1.0.txt. If applicable,
* add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your
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// Copyright (c) 1998, 2007, Oracle. All rights reserved.
package oracle.toplink.essentials.internal.expressions;
import java.util.*;
import oracle.toplink.essentials.querykeys.*;
import oracle.toplink.essentials.expressions.*;
import oracle.toplink.essentials.descriptors.ClassDescriptor;
/**
* This class represents a "query key" that isn't really there
* in the descriptors. For example, I could use this to create
* an 'employee' query key from an 'address' node even if addresses
* don't know their employee. It's called manual, because I will
* have to provide the relevant join criteria myself (normally based
* on a reverse relationship. Motivated by batch reading.
*/
public class ManualQueryKeyExpression extends QueryKeyExpression {
public ManualQueryKeyExpression() {
super();
}
public ManualQueryKeyExpression(String impliedRelationshipName, Expression base) {
super(impliedRelationshipName, base);
}
public ManualQueryKeyExpression(String impliedRelationshipName, Expression base, ClassDescriptor descriptor) {
super(impliedRelationshipName, base);
this.descriptor = descriptor;
}
/**
* INTERNAL:
* Used for debug printing.
*/
public String descriptionOfNodeType() {
return "Manual Query Key";
}
/**
* INTERNAL:
* If we ever get in the circumstance of a manual query key
* to an aggregate, then we can assume that the owner of that
* aggregate isn't participating (and even if it is, we can't
* know which node it is, so *DO* use the aggregate's parents tables
*/
public Vector getOwnedTables() {
if (getDescriptor() == null) {
return null;
} else {
return getDescriptor().getTables();
}
}
public QueryKey getQueryKeyOrNull() {
return null;
}
/**
* INTERNAL:
* We can never be an attribute, we're always a join
*/
public boolean isAttribute() {
return false;
}
public Expression mappingCriteria() {
return null;
}
/**
* INTERNAL:
* This expression is built on a different base than the one we want. Rebuild it and
* return the root of the new tree
*/
public Expression rebuildOn(Expression newBase) {
ObjectExpression newLocalBase = (ObjectExpression)getBaseExpression().rebuildOn(newBase);
return newLocalBase.getManualQueryKey(getName(), getDescriptor());
}
/**
* INTERNAL:
* Rebuild myself against the base, with the values of parameters supplied by the context
* expression. This is used for transforming a standalone expression (e.g. the join criteria of a mapping)
* into part of some larger expression. You normally would not call this directly, instead calling twist
* See the comment there for more details"
*/
public Expression twistedForBaseAndContext(Expression newBase, Expression context) {
ObjectExpression twistedBase = (ObjectExpression)getBaseExpression().twistedForBaseAndContext(newBase, context);
return twistedBase.getManualQueryKey(getName(), getDescriptor());
}
/**
* Do any required validation for this node. Throw an exception if it's incorrect.
*/
public void validateNode() {
// Override super.validateNode() because those criteria don't apply to us
}
}