| /* |
| * 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.spark.converter; |
| |
| import org.apache.pig.backend.executionengine.ExecException; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.POStatus; |
| import org.apache.pig.backend.hadoop.executionengine.physicalLayer.Result; |
| import org.apache.pig.data.Tuple; |
| |
| abstract class OutputConsumerIterator implements java.util.Iterator<Tuple> { |
| private final java.util.Iterator<Tuple> input; |
| private Result result = null; |
| private boolean returned = true; |
| private boolean done = false; |
| |
| OutputConsumerIterator(java.util.Iterator<Tuple> input) { |
| this.input = input; |
| } |
| |
| abstract protected void attach(Tuple tuple); |
| |
| abstract protected Result getNextResult() throws ExecException; |
| |
| /** |
| * Certain operators may buffer the output. |
| * We need to flush the last set of records from such operators, |
| * when we encounter the last input record, before calling |
| * getNextTuple() for the last time. |
| */ |
| abstract protected void endOfInput(); |
| |
| private void readNext() { |
| while (true) { |
| try { |
| // result is set in hasNext() call and returned |
| // to the user in next() call |
| if (result != null && !returned) { |
| return; |
| } |
| |
| if (result == null) { |
| if (!input.hasNext()) { |
| done = true; |
| return; |
| } |
| Tuple v1 = input.next(); |
| attach(v1); |
| } |
| |
| if (!input.hasNext()) { |
| endOfInput(); |
| } |
| |
| result = getNextResult(); |
| returned = false; |
| switch (result.returnStatus) { |
| case POStatus.STATUS_OK: |
| returned = false; |
| break; |
| case POStatus.STATUS_NULL: |
| returned = true; |
| break; |
| case POStatus.STATUS_EOP: |
| done = !input.hasNext(); |
| if (!done) { |
| result = null; |
| } |
| break; |
| case POStatus.STATUS_ERR: |
| throw new RuntimeException("Error while processing " + result); |
| } |
| |
| } catch (ExecException e) { |
| throw new RuntimeException(e); |
| } |
| } |
| } |
| |
| @Override |
| public boolean hasNext() { |
| readNext(); |
| return !done; |
| } |
| |
| @Override |
| public Tuple next() { |
| readNext(); |
| if (done) { |
| throw new RuntimeException("Past the end. Call hasNext() before calling next()"); |
| } |
| if (result == null || result.returnStatus != POStatus.STATUS_OK) { |
| throw new RuntimeException("Unexpected response code from operator: " |
| + result); |
| } |
| returned = true; |
| return (Tuple) result.result; |
| } |
| |
| @Override |
| public void remove() { |
| throw new UnsupportedOperationException(); |
| } |
| } |