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org.apache.cayenne.ejbql.parser.Compiler Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* 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.ejbql.parser;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.cayenne.ejbql.EJBQLBaseVisitor;
import org.apache.cayenne.ejbql.EJBQLCompiledExpression;
import org.apache.cayenne.ejbql.EJBQLException;
import org.apache.cayenne.ejbql.EJBQLExpression;
import org.apache.cayenne.ejbql.EJBQLExpressionVisitor;
import org.apache.cayenne.map.DbAttribute;
import org.apache.cayenne.map.DbJoin;
import org.apache.cayenne.map.DbRelationship;
import org.apache.cayenne.map.Entity;
import org.apache.cayenne.map.EntityResolver;
import org.apache.cayenne.map.EntityResult;
import org.apache.cayenne.map.ObjAttribute;
import org.apache.cayenne.map.ObjRelationship;
import org.apache.cayenne.map.SQLResult;
import org.apache.cayenne.query.PrefetchTreeNode;
import org.apache.cayenne.reflect.ArcProperty;
import org.apache.cayenne.reflect.AttributeProperty;
import org.apache.cayenne.reflect.ClassDescriptor;
import org.apache.cayenne.reflect.Property;
import org.apache.cayenne.reflect.PropertyVisitor;
import org.apache.cayenne.reflect.ToManyProperty;
import org.apache.cayenne.reflect.ToOneProperty;
/**
* Produces an {@link EJBQLCompiledExpression} out of an EJBQL expression tree.
*
* @since 3.0
*/
class Compiler {
// a flag indicating whether column expressions should be treated as result columns or
// not.
private boolean appendingResultColumns;
private String rootId;
private EntityResolver resolver;
private Map descriptorsById;
private Map incomingById;
private Collection paths;
private EJBQLExpressionVisitor fromItemVisitor;
private EJBQLExpressionVisitor joinVisitor;
private EJBQLExpressionVisitor pathVisitor;
private EJBQLExpressionVisitor rootDescriptorVisitor;
private List resultComponents;
private PrefetchTreeNode prefetchTree = null;
Compiler(EntityResolver resolver) {
this.resolver = resolver;
this.descriptorsById = new HashMap();
this.incomingById = new HashMap();
this.rootDescriptorVisitor = new SelectExpressionVisitor();
this.fromItemVisitor = new FromItemVisitor();
this.joinVisitor = new JoinVisitor();
this.pathVisitor = new PathVisitor();
}
CompiledExpression compile(String source, EJBQLExpression parsed) {
parsed.visit(new CompilationVisitor());
Map pathsInSelect = new HashMap();
for (int i = 0; i < parsed.getChildrenCount(); i++) {
if (parsed.getChild(i) instanceof EJBQLSelectClause) {
EJBQLExpression parsedTemp = parsed.getChild(i);
boolean stop = false;
while (parsedTemp.getChildrenCount() > 0 && !stop) {
EJBQLExpression newParsedTemp = null;
for (int j = 0; j < parsedTemp.getChildrenCount(); j++) {
if (parsedTemp.getChild(j) instanceof EJBQLSelectExpression) {
for (int k = 0; k < parsedTemp
.getChild(j)
.getChildrenCount(); k++) {
if (parsedTemp.getChild(j).getChild(k) instanceof EJBQLPath) {
pathsInSelect.put((EJBQLPath) parsedTemp
.getChild(j)
.getChild(k), j);
}
}
}
else {
if (parsedTemp.getChild(j).getChildrenCount() == 0) {
stop = true;
}
else {
newParsedTemp = parsedTemp.getChild(j);
}
}
}
if (!stop && newParsedTemp != null) {
parsedTemp = newParsedTemp;
}
else {
stop = true;
}
}
}
}
// postprocess paths, now that all id vars are resolved
if (paths != null) {
for (EJBQLPath path : paths) {
String id = normalizeIdPath(path.getId());
ClassDescriptor descriptor = descriptorsById.get(id);
if (descriptor == null) {
throw new EJBQLException("Unmapped id variable: " + id);
}
StringBuilder buffer = new StringBuilder(id);
ObjRelationship incoming = null;
String pathRelationshipString = "";
for (int i = 1; i < path.getChildrenCount(); i++) {
String pathChunk = path.getChild(i).getText();
buffer.append('.').append(pathChunk);
Property property = descriptor.getProperty(pathChunk);
if (property instanceof ArcProperty) {
incoming = ((ArcProperty) property).getRelationship();
descriptor = ((ArcProperty) property).getTargetDescriptor();
pathRelationshipString = buffer.substring(0, buffer.length());
descriptorsById.put(pathRelationshipString, descriptor);
incomingById.put(pathRelationshipString, incoming);
}
}
if (pathsInSelect.size() > 0
&& incoming != null
&& pathRelationshipString.length() > 0
&& pathRelationshipString.equals(buffer.toString())) {
EJBQLIdentifier ident = new EJBQLIdentifier(0);
ident.text = pathRelationshipString;
Integer integer = pathsInSelect.get(path);
if (integer != null) {
resultComponents.remove(integer.intValue());
resultComponents.add(integer, ident);
rootId = pathRelationshipString;
}
}
}
}
CompiledExpression compiled = new CompiledExpression();
compiled.setExpression(parsed);
compiled.setSource(source);
compiled.setRootId(rootId);
compiled.setDescriptorsById(descriptorsById);
compiled.setIncomingById(incomingById);
compiled.setPrefetchTree(prefetchTree);
if (resultComponents != null) {
SQLResult mapping = new SQLResult();
for (int i = 0; i < resultComponents.size(); i++) {
Object nextMapping = resultComponents.get(i);
if (nextMapping instanceof String) {
mapping.addColumnResult((String) nextMapping);
}
else if (nextMapping instanceof EJBQLExpression) {
EntityResult compileEntityResult = compileEntityResult(
(EJBQLExpression) nextMapping,
i);
if (prefetchTree != null) {
for (PrefetchTreeNode prefetch : prefetchTree.getChildren()) {
if (((EJBQLExpression) nextMapping).getText().equals(
prefetch.getEjbqlPathEntityId())) {
EJBQLIdentifier ident = new EJBQLIdentifier(0);
ident.text = prefetch.getEjbqlPathEntityId()
+ "."
+ prefetch.getPath();
compileEntityResult = compileEntityResultWithPrefetch(
compileEntityResult,
ident);
}
}
}
mapping.addEntityResult(compileEntityResult);
}
}
compiled.setResult(mapping);
}
return compiled;
}
private EntityResult compileEntityResultWithPrefetch(
EntityResult compiledResult,
EJBQLExpression prefetchExpression) {
final EntityResult result = compiledResult;
String id = prefetchExpression.getText().toLowerCase();
ClassDescriptor descriptor = descriptorsById.get(id);
if (descriptor == null) {
descriptor = descriptorsById.get(prefetchExpression.getText());
}
final String prefix = prefetchExpression.getText().substring(
prefetchExpression.getText().indexOf(".") + 1);
final Set visited = new HashSet();
PropertyVisitor visitor = new PropertyVisitor() {
public boolean visitAttribute(AttributeProperty property) {
ObjAttribute oa = property.getAttribute();
if (visited.add(oa.getDbAttributePath())) {
result.addObjectField(oa.getEntity().getName(), "fetch."
+ prefix
+ "."
+ oa.getName(), prefix + "." + oa.getDbAttributeName());
}
return true;
}
public boolean visitToMany(ToManyProperty property) {
return true;
}
public boolean visitToOne(ToOneProperty property) {
ObjRelationship rel = property.getRelationship();
DbRelationship dbRel = rel.getDbRelationships().get(0);
for (DbJoin join : dbRel.getJoins()) {
DbAttribute src = join.getSource();
if (src.isForeignKey() && visited.add(src.getName())) {
result.addDbField("fetch." + prefix + "." + src.getName(), prefix
+ "."
+ src.getName());
}
}
return true;
}
};
descriptor.visitAllProperties(visitor);
// append id columns ... (some may have been appended already via relationships)
for (String pkName : descriptor.getEntity().getPrimaryKeyNames()) {
if (visited.add(pkName)) {
result
.addDbField("fetch." + prefix + "." + pkName, prefix
+ "."
+ pkName);
}
}
// append inheritance discriminator columns...
for (ObjAttribute column : descriptor.getDiscriminatorColumns()) {
if (visited.add(column.getName())) {
result.addDbField(
"fetch." + prefix + "." + column.getDbAttributePath(),
prefix + "." + column.getDbAttributePath());
}
}
return result;
}
private EntityResult compileEntityResult(EJBQLExpression expression, int position) {
String id = expression.getText().toLowerCase();
ClassDescriptor descriptor = descriptorsById.get(id);
if (descriptor == null) {
descriptor = descriptorsById.get(expression.getText());
}
if(descriptor == null) {
throw new EJBQLException("the entity variable '" + id +"' does not refer to any entity in the FROM clause");
}
final EntityResult entityResult = new EntityResult(descriptor.getObjectClass());
final String prefix = "ec" + position + "_";
final int[] index = {
0
};
final Set visited = new HashSet();
PropertyVisitor visitor = new PropertyVisitor() {
public boolean visitAttribute(AttributeProperty property) {
ObjAttribute oa = property.getAttribute();
if (visited.add(oa.getDbAttributePath())) {
entityResult.addObjectField(
oa.getEntity().getName(),
oa.getName(),
prefix + index[0]++);
}
return true;
}
public boolean visitToMany(ToManyProperty property) {
return true;
}
public boolean visitToOne(ToOneProperty property) {
ObjRelationship rel = property.getRelationship();
DbRelationship dbRel = rel.getDbRelationships().get(0);
for (DbJoin join : dbRel.getJoins()) {
DbAttribute src = join.getSource();
if (src.isForeignKey() && visited.add(src.getName())) {
entityResult.addDbField(src.getName(), prefix + index[0]++);
}
}
return true;
}
};
descriptor.visitAllProperties(visitor);
// append id columns ... (some may have been appended already via relationships)
for (String pkName : descriptor.getEntity().getPrimaryKeyNames()) {
if (visited.add(pkName)) {
entityResult.addDbField(pkName, prefix + index[0]++);
}
}
// append inheritance discriminator columns...
for (ObjAttribute column : descriptor.getDiscriminatorColumns()) {
if (visited.add(column.getName())) {
entityResult.addDbField(column.getDbAttributePath(), prefix + index[0]++);
}
}
return entityResult;
}
private void addPath(EJBQLPath path) {
if (paths == null) {
paths = new ArrayList();
}
paths.add(path);
}
static String normalizeIdPath(String idPath) {
// per JPA spec, 4.4.2, "Identification variables are case insensitive."
int pathSeparator = idPath.indexOf('.');
return pathSeparator < 0 ? idPath.toLowerCase() : idPath.substring(
0,
pathSeparator).toLowerCase()
+ idPath.substring(pathSeparator);
}
class CompilationVisitor extends EJBQLBaseVisitor {
@Override
public boolean visitSelect(EJBQLExpression expression) {
appendingResultColumns = true;
return true;
}
@Override
public boolean visitFrom(EJBQLExpression expression, int finishedChildIndex) {
appendingResultColumns = false;
return true;
}
@Override
public boolean visitSelectExpression(EJBQLExpression expression) {
expression.visit(rootDescriptorVisitor);
return false;
}
@Override
public boolean visitFromItem(EJBQLFromItem expression, int finishedChildIndex) {
expression.visit(fromItemVisitor);
return false;
}
@Override
public boolean visitInnerFetchJoin(EJBQLJoin join) {
prepareFetchJoin(join);
join.visit(joinVisitor);
return false;
}
@Override
public boolean visitInnerJoin(EJBQLJoin join) {
join.visit(joinVisitor);
return false;
}
@Override
public boolean visitOuterFetchJoin(EJBQLJoin join) {
prepareFetchJoin(join);
join.visit(joinVisitor);
return false;
}
@Override
public boolean visitOuterJoin(EJBQLJoin join) {
join.visit(joinVisitor);
return false;
}
@Override
public boolean visitWhere(EJBQLExpression expression) {
expression.visit(pathVisitor);
// continue with children as there may be subselects with their own id
// variable declarations
return true;
}
@Override
public boolean visitOrderBy(EJBQLExpression expression) {
expression.visit(pathVisitor);
return false;
}
@Override
public boolean visitSubselect(EJBQLExpression expression) {
return super.visitSubselect(expression);
}
private void prepareFetchJoin(EJBQLJoin join) {
if (prefetchTree == null) {
prefetchTree = new PrefetchTreeNode();
}
EJBQLPath fetchJoin = (EJBQLPath) join.getChild(0);
addPath(fetchJoin);
PrefetchTreeNode node = prefetchTree.addPath(fetchJoin.getRelativePath());
node.setSemantics(PrefetchTreeNode.JOINT_PREFETCH_SEMANTICS);
node.setPhantom(false);
node.setEjbqlPathEntityId(fetchJoin.getChild(0).getText());
}
}
class FromItemVisitor extends EJBQLBaseVisitor {
private String entityName;
@Override
public boolean visitFromItem(EJBQLFromItem expression, int finishedChildIndex) {
if (finishedChildIndex + 1 == expression.getChildrenCount()) {
// resolve class descriptor
ClassDescriptor descriptor = resolver.getClassDescriptor(entityName);
if (descriptor == null) {
throw new EJBQLException("Unmapped abstract schema name: "
+ entityName);
}
// per JPA spec, 4.4.2, "Identification variables are case insensitive."
String id = normalizeIdPath(expression.getId());
ClassDescriptor old = descriptorsById.put(id, descriptor);
if (old != null && old != descriptor) {
throw new EJBQLException(
"Duplicate identification variable definition: "
+ id
+ ", it is already used for "
+ old.getEntity().getName());
}
// if root wasn't detected in the Select Clause, use the first id var as
// root
if (Compiler.this.rootId == null) {
Compiler.this.rootId = id;
}
this.entityName = null;
}
return true;
}
@Override
public boolean visitIdentificationVariable(EJBQLExpression expression) {
entityName = expression.getText();
return true;
}
}
class JoinVisitor extends EJBQLBaseVisitor {
private String id;
private ObjRelationship incoming;
private ClassDescriptor descriptor;
@Override
public boolean visitPath(EJBQLExpression expression, int finishedChildIndex) {
if (finishedChildIndex + 1 < expression.getChildrenCount()) {
this.id = normalizeIdPath(((EJBQLPath) expression).getId());
this.descriptor = descriptorsById.get(id);
if (descriptor == null) {
throw new EJBQLException("Unmapped id variable: " + id);
}
}
return true;
}
@Override
public boolean visitIdentificationVariable(EJBQLExpression expression) {
Property property = descriptor.getProperty(expression.getText());
if (property instanceof ArcProperty) {
incoming = ((ArcProperty) property).getRelationship();
descriptor = ((ArcProperty) property).getTargetDescriptor();
}
else {
throw new EJBQLException("Incorrect relationship path: "
+ expression.getText());
}
return true;
}
@Override
public boolean visitIdentifier(EJBQLExpression expression) {
if (incoming != null) {
String aliasId = expression.getText().toLowerCase();
// map id variable to class descriptor
ClassDescriptor old = descriptorsById.put(aliasId, descriptor);
if (old != null && old != descriptor) {
throw new EJBQLException(
"Duplicate identification variable definition: "
+ aliasId
+ ", it is already used for "
+ old.getEntity().getName());
}
incomingById.put(aliasId, incoming);
id = null;
descriptor = null;
incoming = null;
}
return true;
}
}
class PathVisitor extends EJBQLBaseVisitor {
@Override
public boolean visitPath(EJBQLExpression expression, int finishedChildIndex) {
addPath((EJBQLPath) expression);
return false;
}
}
class SelectExpressionVisitor extends EJBQLBaseVisitor {
@Override
public boolean visitIdentifier(EJBQLExpression expression) {
if (appendingResultColumns) {
rootId = normalizeIdPath(expression.getText());
addEntityResult(expression);
}
return false;
}
@Override
public boolean visitAggregate(EJBQLExpression expression) {
addResultSetColumn();
expression.getChild(0).getChild(0).visit(pathVisitor);
return false;
}
@Override
public boolean visitPath(EJBQLExpression expression, int finishedChildIndex) {
addPath((EJBQLPath) expression);
addResultSetColumn();
return false;
}
private void addEntityResult(EJBQLExpression expression) {
if (appendingResultColumns) {
if (resultComponents == null) {
resultComponents = new ArrayList();
}
// defer EntityResult creation until we resolve all ids...
resultComponents.add(expression);
}
}
private void addResultSetColumn() {
if (appendingResultColumns) {
if (resultComponents == null) {
resultComponents = new ArrayList();
}
String column = "sc" + resultComponents.size();
resultComponents.add(column);
}
}
}
}
