/*
* JBoss, Home of Professional Open Source.
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership. Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*/
package org.teiid.query.sql.lang;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import org.teiid.core.types.DataTypeManager;
import org.teiid.query.sql.symbol.Expression;
import org.teiid.query.sql.visitor.SQLStringVisitor;
/**
* This class represents the criteria clause for a query, which defines
* constraints on the data values to be retrieved for each parameter in the
* select clause. <p>
*/
public abstract class Criteria implements Expression {
/**
* Constructs a default instance of this class.
*/
public Criteria() {
}
/**
* Abstract clone method
* @return Deep clone of this criteria
*/
public abstract Object clone();
/**
* Return the parser string.
*/
public String toString() {
return SQLStringVisitor.getSQLString(this);
}
/**
* This utility method will pull apart a tree of criteria by breaking all
* compound AND criteria apart. For instance, ((A=1 AND B=2) AND C=3)
* will be broken into A=1, B=2, C=3.
* @param crit Criteria to break apart
* @return List of Criteria, empty list if crit is null
*/
public static List<Criteria> separateCriteriaByAnd(Criteria crit) {
if(crit == null) {
return Collections.emptyList();
}
List<Criteria> parts = new ArrayList<Criteria>();
separateCriteria(crit, parts);
return parts;
}
public static Criteria combineCriteria(List<Criteria> parts) {
if(parts == null || parts.isEmpty()) {
return null;
}
if (parts.size() == 1) {
return parts.get(0);
}
return new CompoundCriteria(parts);
}
/**
* Helper method for {@link #separateCriteriaByAnd(Criteria)} that
* can be called recursively to collect parts.
* @param crit Crit to break apart
* @param parts Collection to add parts to
*/
private static void separateCriteria(Criteria crit, Collection<Criteria> parts) {
if(crit instanceof CompoundCriteria) {
CompoundCriteria compCrit = (CompoundCriteria) crit;
if(compCrit.getOperator() == CompoundCriteria.AND) {
for (Criteria conjunct : compCrit.getCriteria()) {
separateCriteria(conjunct, parts);
}
} else {
parts.add(crit);
}
} else {
parts.add(crit);
}
}
/**
* This utility method can be used to combine two criteria using an AND.
* If both criteria are null, then null will be returned. If either is null,
* then the other will be returned. If neither is null and the primaryCrit is
* a CompoundCriteria, then the additionalCrit will be added to the primaryCrit
* and the primaryCrit will be returned. If the primaryCrit is not compound, a new
* CompoundCriteria will be created and both criteria will be added to it.
* @param primaryCrit Primary criteria - may be modified
* @param additionalCrit Won't be modified, but will likely be attached to the returned crit
* @return Combined criteria
*/
public static Criteria combineCriteria(Criteria primaryCrit, Criteria additionalCrit) {
return combineCriteria(primaryCrit, additionalCrit, false);
}
public static Criteria combineCriteria(Criteria primaryCrit, Criteria additionalCrit, boolean disjunctively) {
if(primaryCrit == null) {
return additionalCrit;
}
if(additionalCrit == null) {
return primaryCrit;
}
CompoundCriteria compCrit = new CompoundCriteria();
compCrit.setOperator((disjunctively?CompoundCriteria.OR:CompoundCriteria.AND));
if ((primaryCrit instanceof CompoundCriteria) && ((CompoundCriteria)primaryCrit).getOperator() == (disjunctively?CompoundCriteria.OR:CompoundCriteria.AND)) {
compCrit.getCriteria().addAll(((CompoundCriteria)primaryCrit).getCriteria());
} else {
compCrit.addCriteria(primaryCrit);
}
if ((additionalCrit instanceof CompoundCriteria) && ((CompoundCriteria)additionalCrit).getOperator() == (disjunctively?CompoundCriteria.OR:CompoundCriteria.AND)) {
compCrit.getCriteria().addAll(((CompoundCriteria)additionalCrit).getCriteria());
} else {
compCrit.addCriteria(additionalCrit);
}
return compCrit;
}
public static Criteria applyDemorgan(Criteria input) {
if (input instanceof NotCriteria) {
NotCriteria not = (NotCriteria)input;
return not.getCriteria();
}
if (!(input instanceof CompoundCriteria)) {
return new NotCriteria(input);
}
CompoundCriteria compCrit = (CompoundCriteria)input;
int operator = (compCrit.getOperator()==CompoundCriteria.OR)?CompoundCriteria.AND:CompoundCriteria.OR;
List<Criteria> criteria = new ArrayList<Criteria>(compCrit.getCriteria().size());
for (Criteria crit : compCrit.getCriteria()) {
crit = new NotCriteria(crit);
criteria.add(crit);
}
return new CompoundCriteria(operator, criteria);
}
@Override
public Class<?> getType() {
return DataTypeManager.DefaultDataClasses.BOOLEAN;
}
} // END CLASS