/*
* JEF - Copyright 2009-2010 Jiyi (mr.jiyi@gmail.com)
*
* 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 jef.database.meta;
import jef.database.Condition;
import jef.database.DbUtils;
import jef.database.Field;
import jef.database.MetadataContainer;
import jef.database.QueryAlias;
import jef.database.query.Join;
import jef.database.query.JoinElement;
import jef.database.query.JpqlExpression;
import jef.database.query.LazyQueryBindField;
import jef.database.query.Query;
import jef.database.query.RefField;
/**
* 描述一个连接键对
*
* @author Administrator
*
*/
public class JoinKey extends Condition {
private static final long serialVersionUID = 1L;
private boolean isValueField; // 右侧是Field
private boolean isSimple; // 简单模式
private Query<?> leftLock; // 左侧固定查询对象
private Query<?> rightLock; // 右侧固定查询对象
// 左右翻转
public JoinKey flip() {
if (isSimple) {
JoinKey r = new JoinKey((Field) this.value, this.operator, this.field);
r.rightLock = this.leftLock;
r.leftLock = this.rightLock;
return r;
} else {
return this;
}
}
public Query<?> getLeftLock() {
return leftLock;
}
public Query<?> getRightLock() {
return rightLock;
}
/**
* 给定Field和外连接信息，构造连接
*
* @param left
* @param right
*/
public JoinKey(Field left, Field right) {
this(left, Operator.EQUALS, right);
}
public JoinKey(Field field, Operator operator, Object value) {
this.field = field;
this.value = value;
this.operator = operator;
init();
}
private void init() {
// 处理左侧锁定
if (field instanceof RefField) {
if (((RefField) field).isBind()) {
this.leftLock = ((RefField) field).getInstanceQuery(null);
}
field = ((RefField) field).getField();
} else if (field instanceof JpqlExpression) {
JpqlExpression jpql = (JpqlExpression) field;
if (jpql.isBind()) {
this.leftLock = jpql.getInstanceQuery(null);
}
}
isValueField = (value instanceof Field);
if (isValueField) {
// 处理右侧锁定
if (value instanceof RefField) {
if (((RefField) value).isBind()) {
this.rightLock = ((RefField) value).getInstanceQuery(null);
}
value = ((RefField) value).getField();
} else if (value instanceof JpqlExpression) {
if (((JpqlExpression) value).isBind()) {
this.rightLock = ((JpqlExpression) value).getInstanceQuery(null);
}
}
if (!(field instanceof JpqlExpression)) {
if ((value instanceof Enum || value instanceof TupleField) && Operator.EQUALS == operator) {
isSimple = true;
}
}
}
}
public boolean isValueField() {
return isValueField;
}
public boolean isSimple() {
return isSimple;
}
public Field getLeft() {
return field;
}
/**
* 得到Join关系右边的字段
*
* @return
*/
public Field getRightAsField() {
if (isValueField) {
return (Field) value;
} else {
return null;
}
}
public ITableMetadata getLeftTableMeta() {
if (leftLock != null) {
return leftLock.getMeta();
}
return DbUtils.getTableMeta(this.field);
}
public ITableMetadata getRightTableMeta() {
if (rightLock != null) {
return rightLock.getMeta();
}
ITableMetadata meta = null;
if (this.value instanceof LazyQueryBindField) {
meta = ((LazyQueryBindField) value).getMeta();
} else if (value instanceof Field) {
meta = DbUtils.getTableMeta((Field) value);
}
return meta;
}
public void findAndLockLeft(Join left) {
if (leftLock != null)
return;
ITableMetadata meta = DbUtils.getTableMeta(this.field);
if (meta == null)
return;
for (QueryAlias qa : ((Join) left).allElements()) {
if (qa.getQuery().getMeta() == meta) {
this.leftLock = qa.getQuery();
return;
}
}
}
public int validate(JoinElement left, Query<?> obj) {
if (validateLeft(left)) {
return validateRight(obj) ? 1 : 0;
}
if (validateLeft(obj)) {
return (validateRight(left) || validateRight(obj)) ? -1 : 0;
}
return 0;
}
public int validate(ITableMetadata left, ITableMetadata obj) {
if (validateLeft(left)) {
return validateRight(obj) ? 1 : 0;
}
if (validateLeft(obj)) {
return (validateRight(left) || validateRight(obj)) ? -1 : 0;
}
return 0;
}
private boolean validateRight(ITableMetadata obj) {
if (rightLock != null) {
return obj == rightLock.getMeta();
} else {
ITableMetadata meta = null;
if (this.value instanceof MetadataContainer) {
meta = ((MetadataContainer) value).getMeta();
} else if (value instanceof Field && value instanceof Enum) {
meta = DbUtils.getTableMeta((Field) value);
}
return meta==null || meta==obj || meta.getThisType().isAssignableFrom(obj.getThisType());
}
}
private boolean validateLeft(ITableMetadata left) {
if (leftLock != null) {
return left == leftLock.getMeta();
} else if (field == null) {// 纯表达式
return true;
} else {
// 这里从Field获得meta,但有风险，有可能会得到实际用的left的一个父类Meta
ITableMetadata meta = DbUtils.getTableMeta(this.field);
return meta == null || meta == left || meta.getThisType().isAssignableFrom(left.getThisType());
}
}
private boolean validateLeft(JoinElement q) {
if (leftLock != null) {
if (q == leftLock) {
return true;
}
if (q instanceof Join) {
for (QueryAlias qa : ((Join) q).allElements()) {
if (qa.getQuery() == leftLock) {
return true;
}
}
}
} else if (field == null) {// 纯表达式
return true;
} else {
// 这里从Field获得meta,但有风险，实际用的meta可能是这个meta的子类。
ITableMetadata meta = DbUtils.getTableMeta(this.field);
if (meta == null)
return true;
if (q instanceof Query<?>) {
return isMatch(meta, ((Query<?>) q).getMeta());
}
if (q instanceof Join) {
for (QueryAlias qa : ((Join) q).allElements()) {
if (isMatch(meta, qa.getQuery().getMeta())) {
return true;
}
}
}
}
return false;
}
private boolean isMatch(ITableMetadata meta, ITableMetadata meta2) {
if (meta == meta2)
return true;
return meta.getThisType().isAssignableFrom(meta2.getThisType());
}
private boolean validateRight(JoinElement q) {
if (rightLock != null) {
if (q == rightLock) {
return true;
}
if (q instanceof Join) {
for (QueryAlias qa : ((Join) q).allElements()) {
if (qa.getQuery() == rightLock) {
return true;
}
}
}
} else {
ITableMetadata meta = null;
if (this.value instanceof MetadataContainer) {
meta = ((MetadataContainer) value).getMeta();
} else if (value instanceof Field && value instanceof Enum) {
meta = DbUtils.getTableMeta((Field) value);
}
if (meta == null)
return true;
if (q instanceof Query<?>) {
return isMatch(meta, ((Query<?>) q).getMeta());
}
if (q instanceof Join) {
for (QueryAlias qa : ((Join) q).allElements()) {
if (isMatch(meta, qa.getQuery().getMeta())) {
return true;
}
}
}
}
return false;
}
}