/*
* Copyright 2011, Mysema Ltd
*
* Licensed 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 com.mysema.query.types;
import static com.mysema.query.util.CollectionUtils.add;
import java.io.Serializable;
import java.util.Set;
import com.mysema.query.JoinExpression;
import com.mysema.query.QueryMetadata;
/**
* ValidatingVisitor visits expressions and ensures that only known path instances are used
*
* @author tiwe
*
*/
public final class ValidatingVisitor implements Visitor<Set<Expression<?>>, Set<Expression<?>>>, Serializable {
private static final long serialVersionUID = 691350069621050872L;
public static final ValidatingVisitor DEFAULT = new ValidatingVisitor();
private final String errorTemplate;
public ValidatingVisitor() {
this.errorTemplate = "Undeclared path '%s'. Add this path as a source to the query to be able to reference it.";
}
public ValidatingVisitor(String errorTemplate) {
this.errorTemplate = errorTemplate;
}
@Override
public Set<Expression<?>> visit(Constant<?> expr, Set<Expression<?>> known) {
return known;
}
@Override
public Set<Expression<?>> visit(FactoryExpression<?> expr, Set<Expression<?>> known) {
for (Expression<?> arg : expr.getArgs()) {
known = arg.accept(this, known);
}
return known;
}
@Override
public Set<Expression<?>> visit(Operation<?> expr, Set<Expression<?>> known) {
if (expr.getOperator() == Ops.ALIAS) {
known = add(known, expr.getArg(1));
}
for (Expression<?> arg : expr.getArgs()) {
known = arg.accept(this, known);
}
return known;
}
@Override
public Set<Expression<?>> visit(ParamExpression<?> expr, Set<Expression<?>> known) {
return known;
}
@Override
public Set<Expression<?>> visit(Path<?> expr, Set<Expression<?>> known) {
if (!known.contains(expr.getRoot())) {
throw new IllegalArgumentException(String.format(errorTemplate, expr.getRoot()));
}
return known;
}
@Override
public Set<Expression<?>> visit(SubQueryExpression<?> expr, Set<Expression<?>> known) {
Set<Expression<?>> old = known;
final QueryMetadata md = expr.getMetadata();
known = visitJoins(md.getJoins(), known);
for (Expression<?> p : md.getProjection()) {
known = p.accept(this, known);
}
for (OrderSpecifier<?> o : md.getOrderBy()) {
known = o.getTarget().accept(this, known);
}
for (Expression<?> g : md.getGroupBy()) {
known = g.accept(this, known);
}
if (md.getHaving() != null) {
known = md.getHaving().accept(this, known);
}
if (md.getWhere() != null) {
known = md.getWhere().accept(this, known);
}
return old;
}
@Override
public Set<Expression<?>> visit(TemplateExpression<?> expr, Set<Expression<?>> known) {
for (Object arg : expr.getArgs()) {
if (arg instanceof Expression<?>) {
known = ((Expression<?>)arg).accept(this, known);
}
}
return known;
}
private Set<Expression<?>> visitJoins(Iterable<JoinExpression> joins, Set<Expression<?>> known) {
for (JoinExpression j : joins) {
final Expression<?> expr = j.getTarget();
if (expr instanceof Path && ((Path)expr).getMetadata().isRoot()) {
known = add(known, expr);
} else {
known = expr.accept(this, known);
}
if (j.getCondition() != null) {
known = j.getCondition().accept(this, known);
}
}
return known;
}
}