| /* |
| * 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.relationalOperators; |
| |
| import java.util.List; |
| |
| 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.backend.hadoop.executionengine.physicalLayer.plans.PhysicalPlan; |
| import org.apache.pig.data.DataType; |
| import org.apache.pig.data.Tuple; |
| import org.apache.pig.impl.plan.OperatorKey; |
| import org.apache.pig.impl.plan.VisitorException; |
| import org.apache.pig.pen.util.ExampleTuple; |
| |
| public class POLimit extends PhysicalOperator { |
| /** |
| * |
| */ |
| private static final long serialVersionUID = 1L; |
| |
| // Number of limited outputs |
| private long mLimit; |
| |
| // The expression plan |
| private PhysicalPlan expressionPlan; |
| |
| // Counts for outputs processed |
| private transient long soFar = 0; |
| |
| public POLimit(OperatorKey k) { |
| this(k, -1, null); |
| } |
| |
| public POLimit(OperatorKey k, int rp) { |
| this(k, rp, null); |
| } |
| |
| public POLimit(OperatorKey k, List<PhysicalOperator> inputs) { |
| this(k, -1, inputs); |
| } |
| |
| public POLimit(OperatorKey k, int rp, List<PhysicalOperator> inputs) { |
| super(k, rp, inputs); |
| } |
| |
| public void setLimit(long limit) { |
| mLimit = limit; |
| } |
| |
| public long getLimit() { |
| return mLimit; |
| } |
| |
| public PhysicalPlan getLimitPlan() { |
| return expressionPlan; |
| } |
| |
| public void setLimitPlan(PhysicalPlan expressionPlan) { |
| this.expressionPlan = expressionPlan; |
| } |
| |
| /** |
| * Counts the number of tuples processed into static variable soFar, if the number of tuples processed reach the |
| * limit, return EOP; Otherwise, return the tuple |
| */ |
| @Override |
| public Result getNextTuple() throws ExecException { |
| // if it is the first time, evaluate the expression. Otherwise reuse the computed value. |
| if (this.getLimit() < 0 && expressionPlan != null) { |
| PhysicalOperator expression = expressionPlan.getLeaves().get(0); |
| long variableLimit; |
| Result returnValue; |
| switch (expression.getResultType()) { |
| case DataType.LONG: |
| returnValue = expression.getNextLong(); |
| if (returnValue.returnStatus != POStatus.STATUS_OK || returnValue.result == null) |
| throw new RuntimeException("Unable to evaluate Limit expression: " |
| + returnValue); |
| variableLimit = (Long) returnValue.result; |
| break; |
| case DataType.INTEGER: |
| returnValue = expression.getNextInteger(); |
| if (returnValue.returnStatus != POStatus.STATUS_OK || returnValue.result == null) |
| throw new RuntimeException("Unable to evaluate Limit expression: " |
| + returnValue); |
| variableLimit = (Integer) returnValue.result; |
| break; |
| default: |
| throw new RuntimeException("Limit requires an integer parameter"); |
| } |
| if (variableLimit < 0) |
| throw new RuntimeException("Limit requires a zero or a positive integer parameter"); |
| this.setLimit(variableLimit); |
| } |
| Result inp = null; |
| while (true) { |
| // illustrator ignore LIMIT before the post processing |
| if ((illustrator == null || illustrator.getOriginalLimit() != -1) && soFar >= mLimit) { |
| inp = RESULT_EOP; |
| break; |
| } |
| inp = processInput(); |
| if (inp.returnStatus == POStatus.STATUS_EOP || inp.returnStatus == POStatus.STATUS_ERR) |
| break; |
| |
| illustratorMarkup(inp.result, null, 0); |
| |
| soFar++; |
| break; |
| } |
| |
| return inp; |
| } |
| |
| @Override |
| public String name() { |
| return getAliasString() + "Limit - " + mKey.toString(); |
| } |
| |
| @Override |
| public boolean supportsMultipleInputs() { |
| return false; |
| } |
| |
| @Override |
| public boolean supportsMultipleOutputs() { |
| return false; |
| } |
| |
| @Override |
| public void visit(PhyPlanVisitor v) throws VisitorException { |
| v.visitLimit(this); |
| } |
| |
| @Override |
| public void reset() { |
| soFar = 0; |
| } |
| |
| @Override |
| public POLimit clone() throws CloneNotSupportedException { |
| POLimit clone = (POLimit) super.clone(); |
| if (this.expressionPlan != null) { |
| clone.expressionPlan = this.expressionPlan.clone(); |
| } |
| return clone; |
| } |
| |
| @Override |
| public Tuple illustratorMarkup(Object in, Object out, int eqClassIndex) { |
| if(illustrator != null) { |
| ExampleTuple tIn = (ExampleTuple) in; |
| illustrator.getEquivalenceClasses().get(eqClassIndex).add(tIn); |
| illustrator.addData((Tuple) in); |
| } |
| return (Tuple) in; |
| } |
| } |