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Cayenne Object Persistence Framework
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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
* under the License.
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package org.apache.cayenne.access.trans;
import java.util.Iterator;
import java.util.List;
import org.apache.commons.collections.IteratorUtils;
import org.apache.cayenne.DataObject;
import org.apache.cayenne.ObjectId;
import org.apache.cayenne.exp.Expression;
import org.apache.cayenne.exp.TraversalHandler;
import org.apache.cayenne.map.DbAttribute;
import org.apache.cayenne.map.DbRelationship;
import org.apache.cayenne.map.EntityInheritanceTree;
import org.apache.cayenne.map.ObjEntity;
import org.apache.cayenne.query.QualifiedQuery;
import org.apache.cayenne.query.Query;
import org.apache.cayenne.query.SelectQuery;
/**
* Translates query qualifier to SQL. Used as a helper class by query translators.
*
* @author Andrei Adamchik
*/
public class QualifierTranslator
extends QueryAssemblerHelper
implements TraversalHandler {
protected StringBuffer qualBuf = new StringBuffer();
protected boolean translateParentQual;
protected DataObjectMatchTranslator objectMatchTranslator;
protected boolean matchingObject;
public QualifierTranslator() {
this(null);
}
public QualifierTranslator(QueryAssembler queryAssembler) {
super(queryAssembler);
}
/** Translates query qualifier to SQL WHERE clause.
* Qualifier is obtained from queryAssembler object.
*/
public String doTranslation() {
qualBuf.setLength(0);
Expression rootNode = extractQualifier();
if (rootNode == null) {
return null;
}
// build SQL where clause string based on expression
// (using '?' for object values)
rootNode.traverse(this);
return qualBuf.length() > 0 ? qualBuf.toString() : null;
}
protected Expression extractQualifier() {
Query q = queryAssembler.getQuery();
Expression qualifier =
(isTranslateParentQual())
? ((SelectQuery) q).getParentQualifier()
: ((QualifiedQuery) q).getQualifier();
// append Entity qualifiers, taking inheritance into account
ObjEntity entity = getObjEntity();
if (entity != null) {
EntityInheritanceTree tree =
queryAssembler.getEntityResolver().lookupInheritanceTree(
entity);
Expression entityQualifier =
(tree != null)
? tree.qualifierForEntityAndSubclasses()
: entity.getDeclaredQualifier();
if (entityQualifier != null) {
qualifier =
(qualifier != null)
? qualifier.andExp(entityQualifier)
: entityQualifier;
}
}
return qualifier;
}
/**
* Called before processing an expression to initialize
* objectMatchTranslator if needed.
*/
protected void detectObjectMatch(Expression exp) {
// On demand initialization of
// objectMatchTranslator is not possible since there may be null
// object values that would not allow to detect the need for
// such translator in the right time (e.g.: null = dbpath)
matchingObject = false;
if (exp.getOperandCount() != 2) {
// only binary expressions are supported
return;
}
// check if there are DataObjects among direct children of the Expression
for (int i = 0; i < 2; i++) {
Object op = exp.getOperand(i);
if (op instanceof DataObject || op instanceof ObjectId) {
matchingObject = true;
if (objectMatchTranslator == null) {
objectMatchTranslator = new DataObjectMatchTranslator();
}
else {
objectMatchTranslator.reset();
}
break;
}
}
}
protected void appendObjectMatch() {
if (!matchingObject || objectMatchTranslator == null) {
throw new IllegalStateException("An invalid attempt to append object match.");
}
// turn off special handling, so that all the methods behave as a superclass's impl.
matchingObject = false;
boolean first = true;
DbRelationship relationship = objectMatchTranslator.getRelationship();
if(!relationship.isToMany() && !relationship.isToPK()) {
queryAssembler.dbRelationshipAdded(relationship);
}
Iterator it = objectMatchTranslator.keys();
while (it.hasNext()) {
if (first) {
first = false;
}
else {
qualBuf.append(" AND ");
}
String key = (String) it.next();
DbAttribute attr = objectMatchTranslator.getAttribute(key);
Object val = objectMatchTranslator.getValue(key);
processColumn(qualBuf, attr, relationship);
qualBuf.append(objectMatchTranslator.getOperation());
appendLiteral(qualBuf, val, attr, objectMatchTranslator.getExpression());
}
objectMatchTranslator.reset();
}
/** Opportunity to insert an operation */
public void finishedChild(Expression node, int childIndex, boolean hasMoreChildren) {
if (!hasMoreChildren) {
return;
}
StringBuffer buf = (matchingObject) ? new StringBuffer() : qualBuf;
switch (node.getType()) {
case Expression.AND :
buf.append(" AND ");
break;
case Expression.OR :
buf.append(" OR ");
break;
case Expression.EQUAL_TO :
// translate NULL as IS NULL
if (childIndex == 0
&& node.getOperandCount() == 2
&& node.getOperand(1) == null) {
buf.append(" IS ");
}
else {
buf.append(" = ");
}
break;
case Expression.NOT_EQUAL_TO :
// translate NULL as IS NOT NULL
if (childIndex == 0
&& node.getOperandCount() == 2
&& node.getOperand(1) == null) {
buf.append(" IS NOT ");
}
else {
buf.append(" <> ");
}
break;
case Expression.LESS_THAN :
buf.append(" < ");
break;
case Expression.GREATER_THAN :
buf.append(" > ");
break;
case Expression.LESS_THAN_EQUAL_TO :
buf.append(" <= ");
break;
case Expression.GREATER_THAN_EQUAL_TO :
buf.append(" >= ");
break;
case Expression.IN :
buf.append(" IN ");
break;
case Expression.NOT_IN :
buf.append(" NOT IN ");
break;
case Expression.LIKE :
buf.append(" LIKE ");
break;
case Expression.NOT_LIKE :
buf.append(" NOT LIKE ");
break;
case Expression.LIKE_IGNORE_CASE :
buf.append(") LIKE UPPER(");
break;
case Expression.NOT_LIKE_IGNORE_CASE :
buf.append(") NOT LIKE UPPER(");
break;
case Expression.ADD :
buf.append(" + ");
break;
case Expression.SUBTRACT :
buf.append(" - ");
break;
case Expression.MULTIPLY :
buf.append(" * ");
break;
case Expression.DIVIDE :
buf.append(" / ");
break;
case Expression.BETWEEN :
if (childIndex == 0)
buf.append(" BETWEEN ");
else if (childIndex == 1)
buf.append(" AND ");
break;
case Expression.NOT_BETWEEN :
if (childIndex == 0)
buf.append(" NOT BETWEEN ");
else if (childIndex == 1)
buf.append(" AND ");
break;
}
if (matchingObject) {
objectMatchTranslator.setOperation(buf.toString());
objectMatchTranslator.setExpression(node);
}
}
public void startNode(Expression node, Expression parentNode) {
int count = node.getOperandCount();
if (count == 2) {
// binary nodes are the only ones that currently require this
detectObjectMatch(node);
}
if (parenthesisNeeded(node, parentNode)) {
qualBuf.append('(');
}
if (count == 1) {
if (node.getType() == Expression.NEGATIVE)
qualBuf.append('-');
// ignore POSITIVE - it is a NOOP
// else if(node.getType() == Expression.POSITIVE)
// qualBuf.append('+');
else if (node.getType() == Expression.NOT)
qualBuf.append("NOT ");
else if (node.getType() == Expression.EXISTS)
qualBuf.append("EXISTS ");
else if (node.getType() == Expression.ALL)
qualBuf.append("ALL ");
else if (node.getType() == Expression.SOME)
qualBuf.append("SOME ");
else if (node.getType() == Expression.ANY)
qualBuf.append("ANY ");
}
else if (
node.getType() == Expression.LIKE_IGNORE_CASE
|| node.getType() == Expression.NOT_LIKE_IGNORE_CASE) {
qualBuf.append("UPPER(");
}
}
/**
* @since 1.1
*/
public void endNode(Expression node, Expression parentNode) {
// check if we need to use objectMatchTranslator to finish building the expression
if (node.getOperandCount() == 2 && matchingObject) {
appendObjectMatch();
}
if (parenthesisNeeded(node, parentNode)) {
qualBuf.append(')');
}
if (node.getType() == Expression.LIKE_IGNORE_CASE
|| node.getType() == Expression.NOT_LIKE_IGNORE_CASE) {
qualBuf.append(')');
}
}
public void objectNode(Object leaf, Expression parentNode) {
if (parentNode.getType() == Expression.RAW_SQL) {
appendRawSql(leaf);
}
else if (parentNode.getType() == Expression.OBJ_PATH) {
appendObjPath(qualBuf, parentNode);
}
else if (parentNode.getType() == Expression.DB_PATH) {
appendDbPath(qualBuf, parentNode);
}
else if (parentNode.getType() == Expression.LIST) {
appendList(parentNode, paramsDbType(parentNode));
}
else {
appendLiteral(qualBuf, leaf, paramsDbType(parentNode), parentNode);
}
}
protected boolean parenthesisNeeded(Expression node, Expression parentNode) {
if (parentNode == null)
return false;
// only unary expressions can go w/o parenthesis
if (node.getOperandCount() > 1)
return true;
if (node.getType() == Expression.OBJ_PATH)
return false;
if (node.getType() == Expression.DB_PATH)
return false;
return true;
}
private void appendRawSql(Object sql) {
if (sql != null) {
qualBuf.append(sql);
}
}
private final void appendList(Expression listExpr, DbAttribute paramDesc) {
Iterator it = null;
Object list = listExpr.getOperand(0);
if (list instanceof List) {
it = ((List) list).iterator();
}
else if (list instanceof Object[]) {
it = IteratorUtils.arrayIterator((Object[]) list);
}
else {
String className = (list != null) ? list.getClass().getName() : "";
throw new IllegalArgumentException(
"Unsupported type for the list expressions: " + className);
}
// process first element outside the loop
// (unroll loop to avoid condition checking
if (it.hasNext())
appendLiteral(qualBuf, it.next(), paramDesc, listExpr);
else
return;
while (it.hasNext()) {
qualBuf.append(", ");
appendLiteral(qualBuf, it.next(), paramDesc, listExpr);
}
}
/**
* Returns true if this translator will translate
* parent qualifier on call to doTranslation.
*
* @return boolean
*/
public boolean isTranslateParentQual() {
return translateParentQual;
}
/**
* Configures translator to translate
* parent or main qualifier on call to doTranslation.
*
* @param translateParentQual The translateParentQual to set
*/
public void setTranslateParentQual(boolean translateParentQual) {
this.translateParentQual = translateParentQual;
}
public ObjEntity getObjEntity() {
if (isTranslateParentQual()) {
SelectQuery query = (SelectQuery) queryAssembler.getQuery();
return queryAssembler.getEntityResolver().getObjEntity(
query.getParentObjEntityName());
}
else {
return super.getObjEntity();
}
}
protected void appendLiteral(
StringBuffer buf,
Object val,
DbAttribute attr,
Expression parentExpression) {
if (!matchingObject) {
super.appendLiteral(buf, val, attr, parentExpression);
}
else if (val == null || (val instanceof DataObject)) {
objectMatchTranslator.setDataObject((DataObject) val);
}
else if(val instanceof ObjectId) {
objectMatchTranslator.setObjectId((ObjectId) val);
}
else {
throw new IllegalArgumentException("Attempt to use literal other than DataObject during object match.");
}
}
protected void processRelTermination(StringBuffer buf, DbRelationship rel) {
if (!matchingObject) {
super.processRelTermination(buf, rel);
}
else {
if (rel.isToMany()) {
// append joins
queryAssembler.dbRelationshipAdded(rel);
}
objectMatchTranslator.setRelationship(rel);
}
}
}
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