org.teiid.query.sql.lang.From Maven / Gradle / Ivy
/*
* Copyright Red Hat, Inc. and/or its affiliates
* and other contributors as indicated by the @author tags and
* the COPYRIGHT.txt file distributed with this work.
*
* 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 org.teiid.query.sql.lang;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import org.teiid.core.util.EquivalenceUtil;
import org.teiid.core.util.HashCodeUtil;
import org.teiid.query.sql.LanguageObject;
import org.teiid.query.sql.LanguageVisitor;
import org.teiid.query.sql.symbol.GroupSymbol;
import org.teiid.query.sql.visitor.SQLStringVisitor;
/**
* Represents a FROM clause in a SELECT query. The from clause holds a set of
* FROM subclauses. Each FROM subclause can be either a single group
* ({@link UnaryFromClause}) or a join predicate ({@link JoinPredicate}).
*/
public class From implements LanguageObject {
private List clauses;
/**
* Constructs a default instance of this class.
*/
public From() {
clauses = new ArrayList();
}
/**
* Constructs an instance of this class from an ordered set of from clauses
* @param parameters The ordered list of from clauses
*/
public From( List parameters ) {
clauses = new ArrayList( parameters );
}
// =========================================================================
// M E T H O D S
// =========================================================================
/**
* Add a clause to the FROM
* @param clause Add a clause to the FROM
*/
public void addClause(FromClause clause) {
this.clauses.add(clause);
}
/**
* Add clauses to the FROM
* @param clauses Collection of {@link FromClause}s
*/
public void addClauses(Collection toAdd) {
this.clauses.addAll(toAdd);
}
/**
* Get all the clauses in FROM
* @return List of {@link FromClause}
*/
public List getClauses() {
return this.clauses;
}
/**
* Set all the clauses
* @param clauses List of {@link FromClause}
*/
public void setClauses(List clauses) {
this.clauses = clauses;
}
/**
* Adds a new group to the list (it will be wrapped in a UnaryFromClause)
* @param group Group to add
*/
public void addGroup( GroupSymbol group ) {
if( group != null ) {
clauses.add(new UnaryFromClause(group));
}
}
/**
* Adds a new collection of groups to the list
* @param groups Collection of {@link GroupSymbol}
*/
public void addGroups( Collection groups ) {
if(groups != null) {
for (GroupSymbol groupSymbol : groups) {
clauses.add(new UnaryFromClause(groupSymbol));
}
}
}
/**
* Returns an ordered list of the groups in all sub-clauses.
* @return List of {@link GroupSymbol}
*/
public List getGroups() {
List groups = new ArrayList();
if(clauses != null) {
for(int i=0; i