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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.
*/
package org.apache.jackrabbit.oak.query.ast;
import java.util.Set;
import org.apache.jackrabbit.oak.api.PropertyValue;
import org.apache.jackrabbit.oak.query.index.FilterImpl;
import org.apache.jackrabbit.oak.spi.query.PropertyValues;
/**
* The "a.x = b.y" join condition.
*/
public class EquiJoinConditionImpl extends JoinConditionImpl {
private final String property1Name;
private final String property2Name;
private final String selector1Name;
private final String selector2Name;
private SelectorImpl selector1;
private SelectorImpl selector2;
public EquiJoinConditionImpl(String selector1Name, String property1Name, String selector2Name,
String property2Name) {
this.selector1Name = selector1Name;
this.property1Name = property1Name;
this.selector2Name = selector2Name;
this.property2Name = property2Name;
}
@Override
boolean accept(AstVisitor v) {
return v.visit(this);
}
@Override
public String toString() {
return quote(selector1Name) + '.' + quote(property1Name) +
" = " + quote(selector2Name) + '.' + quote(property2Name);
}
public void bindSelector(SourceImpl source) {
selector1 = source.getExistingSelector(selector1Name);
selector2 = source.getExistingSelector(selector2Name);
}
@Override
public boolean evaluate() {
// 6.7.8 EquiJoinCondition
// A node-tuple satisfies the constraint only if:
PropertyValue p1 = selector1.currentProperty(property1Name);
if (p1 == null) {
// the selector1Name node has a property named property1Name, and
return false;
}
PropertyValue p2 = selector2.currentProperty(property2Name);
if (p2 == null) {
// the selector2Name node has a property named property2Name, and
return false;
}
// the value of property property1Name is equal to the value of property property2Name,
// as defined in §3.6.5 Comparison of Values.
// -> that can be interpreted as follows: if the property types
// don't match, then they don't match, however for compatibility
// with Jackrabbit 2.x, we try to convert the values so the property types match
// (for example, convert reference to string)
// See OAK-3416
if (!p1.isArray() && !p2.isArray()) {
// both are single valued
// "the value of operand2 is converted to the
// property type of the value of operand1"
p2 = convertValueToType(p2, p1);
return PropertyValues.match(p1, p2);
}
// TODO what is the expected result of an equi join for multi-valued properties?
if (!p1.isArray() && p2.isArray()) {
p1 = convertValueToType(p1, p2);
if (p1 != null && PropertyValues.match(p1, p2)) {
return true;
}
return false;
} else if (p1.isArray() && !p2.isArray()) {
p2 = convertValueToType(p2, p1);
if (p2 != null && PropertyValues.match(p1, p2)) {
return true;
}
return false;
}
return PropertyValues.match(p1, p2);
}
@Override
public void restrict(FilterImpl f) {
if (f.getSelector().equals(selector1)) {
PropertyValue p2 = selector2.currentProperty(property2Name);
if (p2 == null && f.isPreparing() && f.isPrepared(selector2)) {
// during the prepare phase, if the selector is already
// prepared, then we would know the value
p2 = PropertyValues.newString(KNOWN_VALUE);
}
if (p2 != null) {
if (p2.isArray()) {
// TODO support join on multi-valued properties
p2 = null;
}
}
String p1n = normalizePropertyName(property1Name);
if (p2 == null) {
// always set the condition,
// even if unknown (in which case it is converted to "is not null")
f.restrictProperty(p1n, Operator.NOT_EQUAL, null);
} else {
f.restrictProperty(p1n, Operator.EQUAL, p2);
}
}
if (f.getSelector().equals(selector2)) {
PropertyValue p1 = selector1.currentProperty(property1Name);
if (p1 == null && f.isPreparing() && f.isPrepared(selector1)) {
// during the prepare phase, if the selector is already
// prepared, then we would know the value
p1 = PropertyValues.newString(KNOWN_VALUE);
}
if (p1 != null) {
if (p1.isArray()) {
// TODO support join on multi-valued properties
p1 = null;
}
}
// always set the condition, even if unkown ( -> is not null)
String p2n = normalizePropertyName(property2Name);
f.restrictProperty(p2n, Operator.EQUAL, p1);
}
}
@Override
public void restrictPushDown(SelectorImpl s) {
// both properties may not be null
if (s.equals(selector1)) {
PropertyExistenceImpl ex = new PropertyExistenceImpl(s.getSelectorName(), property1Name);
ex.bindSelector(s);
s.restrictSelector(ex);
} else if (s.equals(selector2)) {
PropertyExistenceImpl ex = new PropertyExistenceImpl(s.getSelectorName(), property2Name);
ex.bindSelector(s);
s.restrictSelector(ex);
}
}
@Override
public boolean isParent(SourceImpl source) {
return false;
}
@Override
public boolean canEvaluate(Set available) {
return available.contains(selector1) && available.contains(selector2);
}
@Override
public AstElement copyOf() {
return new EquiJoinConditionImpl(selector1Name, property1Name, selector2Name, property2Name);
}
}
