/*
* Copyright 1999-2012 Alibaba Group.
*
* 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.
*/
/**
* (created at 2011-2-9)
*/
package com.alibaba.cobar.parser.ast.fragment.tableref;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import com.alibaba.cobar.parser.ast.expression.Expression;
import com.alibaba.cobar.parser.visitor.SQLASTVisitor;
/**
* left or right join
*
* @author <a href="mailto:shuo.qius@alibaba-inc.com">QIU Shuo</a>
*/
public class OuterJoin implements TableReference {
private static List<String> ensureListType(List<String> list) {
if (list == null)
return null;
if (list.isEmpty())
return Collections.emptyList();
if (list instanceof ArrayList)
return list;
return new ArrayList<String>(list);
}
/**
* for MySQL, only <code>LEFT</code> and <code>RIGHT</code> outer join are
* supported
*/
private final boolean isLeftJoin;
private final TableReference leftTableRef;
private final TableReference rightTableRef;
private final Expression onCond;
private final List<String> using;
private OuterJoin(boolean isLeftJoin, TableReference leftTableRef, TableReference rightTableRef, Expression onCond,
List<String> using) {
super();
this.isLeftJoin = isLeftJoin;
this.leftTableRef = leftTableRef;
this.rightTableRef = rightTableRef;
this.onCond = onCond;
this.using = ensureListType(using);
}
public OuterJoin(boolean isLeftJoin, TableReference leftTableRef, TableReference rightTableRef, Expression onCond) {
this(isLeftJoin, leftTableRef, rightTableRef, onCond, null);
}
public OuterJoin(boolean isLeftJoin, TableReference leftTableRef, TableReference rightTableRef, List<String> using) {
this(isLeftJoin, leftTableRef, rightTableRef, null, using);
}
public boolean isLeftJoin() {
return isLeftJoin;
}
public TableReference getLeftTableRef() {
return leftTableRef;
}
public TableReference getRightTableRef() {
return rightTableRef;
}
public Expression getOnCond() {
return onCond;
}
public List<String> getUsing() {
return using;
}
@Override
public Object removeLastConditionElement() {
return null;
}
@Override
public boolean isSingleTable() {
return false;
}
@Override
public int getPrecedence() {
return TableReference.PRECEDENCE_JOIN;
}
@Override
public void accept(SQLASTVisitor visitor) {
visitor.visit(this);
}
}