| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators; |
| |
| |
| import java.util.List; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.pig.backend.executionengine.ExecException; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.POStatus; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.Result; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhyPlanVisitor; |
| import org.apache.pig.impl.plan.OperatorKey; |
| import org.apache.pig.impl.plan.VisitorException; |
| import org.apache.pig.pen.Illustrator; |
| |
| /** |
| * A base class for all types of expressions. All expression |
| * operators must extend this class. |
| * |
| */ |
| |
| public abstract class ExpressionOperator extends PhysicalOperator { |
| private static final Log log = LogFactory.getLog(ExpressionOperator.class); |
| private static final long serialVersionUID = 1L; |
| |
| public ExpressionOperator(OperatorKey k) { |
| this(k,-1); |
| } |
| |
| public ExpressionOperator(OperatorKey k, int rp) { |
| super(k, rp); |
| } |
| |
| @Override |
| public void setIllustrator(Illustrator illustrator) { |
| this.illustrator = illustrator; |
| } |
| |
| @Override |
| public boolean supportsMultipleOutputs() { |
| return false; |
| } |
| |
| @Override |
| public Result getNextDataBag() throws ExecException { |
| return new Result(); |
| } |
| |
| @Override |
| public abstract void visit(PhyPlanVisitor v) throws VisitorException; |
| |
| |
| /** |
| * Make a deep copy of this operator. This is declared here to make it |
| * possible to call clone on ExpressionOperators. |
| * @throws CloneNotSupportedException |
| */ |
| @Override |
| public ExpressionOperator clone() throws CloneNotSupportedException { |
| String s = "This expression operator does not implement clone."; |
| log.error(s); |
| throw new CloneNotSupportedException(s); |
| } |
| |
| /** |
| * Get the sub-expressions of this expression. |
| * This is called if reducer is run as accumulative mode, all the child |
| * expression must be called if they have any UDF to drive the UDF.accumulate() |
| */ |
| protected abstract List<ExpressionOperator> getChildExpressions(); |
| |
| /** check whether this expression contains any UDF |
| * this is called if reducer is run as accumulative mode |
| * in this case, all UDFs must be called |
| */ |
| public boolean containUDF() { |
| if (this instanceof POUserFunc) { |
| return true; |
| } |
| |
| List<ExpressionOperator> l = getChildExpressions(); |
| if (l != null) { |
| for(ExpressionOperator e: l) { |
| if (e.containUDF()) { |
| return true; |
| } |
| } |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Drive all the UDFs in accumulative mode |
| */ |
| protected Result accumChild(List<ExpressionOperator> child, byte dataType) throws ExecException { |
| try { |
| if (isAccumStarted()) { |
| if (child == null) { |
| child = getChildExpressions(); |
| } |
| Result res = null; |
| if (child != null) { |
| for(ExpressionOperator e: child) { |
| if (e.containUDF()) { |
| res = e.getNext(dataType); |
| if (res.returnStatus != POStatus.STATUS_BATCH_OK) { |
| return res; |
| } |
| } |
| } |
| } |
| |
| res = new Result(); |
| res.returnStatus = POStatus.STATUS_BATCH_OK; |
| |
| return res; |
| } |
| |
| return null; |
| } catch (RuntimeException e) { |
| throw new ExecException("Exception while executing " + this.toString() + ": " + e.toString(), e); |
| } |
| } |
| |
| @Override |
| public String toString() { |
| return "[" + this.getClass().getSimpleName() + " " + super.toString() + " children: " + getChildExpressions() + " at " + getOriginalLocations() + "]"; |
| } |
| } |