| /* |
| * Copyright 2009-2010 by The Regents of the University of California |
| * 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 from |
| * |
| * 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 edu.uci.ics.hyracks.algebricks.core.algebra.base; |
| |
| import java.util.Collection; |
| import java.util.List; |
| import java.util.Map; |
| |
| import org.apache.commons.lang3.mutable.Mutable; |
| |
| import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException; |
| import edu.uci.ics.hyracks.algebricks.core.algebra.properties.FunctionalDependency; |
| import edu.uci.ics.hyracks.algebricks.core.algebra.visitors.ILogicalExpressionVisitor; |
| |
| public interface ILogicalExpression { |
| |
| public LogicalExpressionTag getExpressionTag(); |
| |
| public abstract <R, T> R accept(ILogicalExpressionVisitor<R, T> visitor, T arg) throws AlgebricksException; |
| |
| public void getUsedVariables(Collection<LogicalVariable> vars); |
| |
| public void substituteVar(LogicalVariable v1, LogicalVariable v2); |
| |
| // constraints (e.g., FDs, equivalences) |
| |
| /** |
| * @param fds |
| * Output argument: functional dependencies that can be inferred |
| * from this expression. |
| * @param equivClasses |
| * Output argument: Equivalence classes that can be inferred from |
| * this expression. |
| */ |
| public void getConstraintsAndEquivClasses(Collection<FunctionalDependency> fds, |
| Map<LogicalVariable, EquivalenceClass> equivClasses); |
| |
| /** |
| * @param fds |
| * Output argument: functional dependencies that can be inferred |
| * from this expression. |
| * @param outerVars |
| * Input argument: variables coming from outer branch(es), e.g., |
| * the left branch of a left outer join. |
| */ |
| public void getConstraintsForOuterJoin(Collection<FunctionalDependency> fds, Collection<LogicalVariable> outerVars); |
| |
| /** |
| * @param conjs |
| * Output argument: a list of expression whose conjunction, in |
| * any order, can replace the current expression. |
| * @return true if the expression can be broken in at least two conjuncts, |
| * false otherwise. |
| */ |
| public boolean splitIntoConjuncts(List<Mutable<ILogicalExpression>> conjs); |
| |
| public abstract ILogicalExpression cloneExpression(); |
| } |