| /* |
| * 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.properties; |
| |
| import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException; |
| import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable; |
| import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.IOperatorSchema; |
| |
| public abstract class VariablePropagationPolicy { |
| public static final VariablePropagationPolicy ALL = new VariablePropagationPolicy() { |
| @Override |
| public void propagateVariables(IOperatorSchema target, IOperatorSchema... sources) { |
| int n = sources.length; |
| for (int i = 0; i < n; i++) { |
| target.addAllNewVariables(sources[i]); |
| } |
| } |
| }; |
| |
| public static final VariablePropagationPolicy NONE = new VariablePropagationPolicy() { |
| @Override |
| public void propagateVariables(IOperatorSchema target, IOperatorSchema... sources) { |
| // do nothing |
| } |
| }; |
| |
| /** |
| * Adds, from each source, only variables that do not already appear in the |
| * target. |
| * |
| * |
| */ |
| public static final VariablePropagationPolicy ADDNEWVARIABLES = new VariablePropagationPolicy() { |
| @Override |
| public void propagateVariables(IOperatorSchema target, IOperatorSchema... sources) { |
| for (IOperatorSchema s : sources) { |
| for (LogicalVariable v : s) { |
| if (target.findVariable(v) < 0) { |
| target.addVariable(v); |
| } |
| } |
| } |
| } |
| }; |
| |
| public abstract void propagateVariables(IOperatorSchema target, IOperatorSchema... sources) |
| throws AlgebricksException; |
| |
| public static VariablePropagationPolicy concat(final VariablePropagationPolicy... policies) { |
| return new VariablePropagationPolicy() { |
| @Override |
| public void propagateVariables(IOperatorSchema target, IOperatorSchema... sources) |
| throws AlgebricksException { |
| if (policies.length != sources.length) { |
| throw new IllegalArgumentException(); |
| } |
| for (int i = 0; i < policies.length; ++i) { |
| VariablePropagationPolicy p = policies[i]; |
| IOperatorSchema s = sources[i]; |
| p.propagateVariables(target, s); |
| } |
| } |
| }; |
| } |
| |
| } |