/**
* 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.hadoop.hive.ql.exec;
import java.util.ArrayList;
import java.util.List;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.plan.ptf.WindowFrameDef;
import org.apache.hadoop.hive.serde2.AbstractSerDe;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorUtils;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorUtils.ObjectInspectorCopyOption;
import org.apache.hadoop.hive.serde2.objectinspector.StructObjectInspector;
public class PTFRollingPartition extends PTFPartition {
/*
* num rows whose output is evaluated.
*/
int numRowsProcessed;
/*
* Relative start position of the windowing. Can be negative.
*/
int startPos;
/*
* Relative end position of the windowing. Can be negative.
*/
int endPos;
/*
* number of rows received.
*/
int numRowsReceived;
/*
* State of the Rolling Partition
*
* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 x10 x11 x12 x13 x14 x15 x16 x17
* ^ ^ ^
* | | |
* |--preceding span--numRowsProcessed---followingSpan --numRowsRecived
*
* a. index x7 : represents the last output row
* b. so preceding span rows before that are still held on for subsequent rows processing.
* c. The #of rows beyond numRowsProcessed = followingSpan
*/
/*
* cache of rows; guaranteed to contain precedingSpan rows before
* nextRowToProcess.
*/
List<Object> currWindow;
protected PTFRollingPartition(Configuration cfg, AbstractSerDe serDe,
StructObjectInspector inputOI, StructObjectInspector outputOI,
int startPos, int endPos) throws HiveException {
super(cfg, serDe, inputOI, outputOI, false);
this.startPos = startPos;
this.endPos = endPos;
currWindow = new ArrayList<Object>(endPos - startPos + 1);
}
public void reset() throws HiveException {
currWindow.clear();
numRowsProcessed = 0;
numRowsReceived = 0;
}
public Object getAt(int i) throws HiveException {
int rangeStart = numRowsReceived - currWindow.size();
return currWindow.get(i - rangeStart);
}
public void append(Object o) throws HiveException {
@SuppressWarnings("unchecked")
List<Object> l = (List<Object>) ObjectInspectorUtils.copyToStandardObject(
o, inputOI, ObjectInspectorCopyOption.WRITABLE);
currWindow.add(l);
numRowsReceived++;
}
public Object nextOutputRow() throws HiveException {
Object row = getAt(numRowsProcessed);
numRowsProcessed++;
if (numRowsProcessed > -startPos) {
currWindow.remove(0);
}
return row;
}
public boolean processedAllRows() {
return numRowsProcessed >= numRowsReceived;
}
/**
* Gets the next row index that the data within the window are available and can be processed
* @param wFrameDef
* @return
*/
public int rowToProcess(WindowFrameDef wFrameDef) {
int rowToProcess = numRowsReceived - 1 - Math.max(0, wFrameDef.getEnd().getRelativeOffset());
return rowToProcess >= 0 ? rowToProcess : -1;
}
public int size() {
return numRowsReceived;
}
public PTFPartitionIterator<Object> iterator() throws HiveException {
return new RollingPItr();
}
public void close() {
}
class RollingPItr implements PTFPartitionIterator<Object> {
@Override
public boolean hasNext() {
throw new UnsupportedOperationException();
}
@Override
public Object next() {
throw new UnsupportedOperationException();
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
@Override
public int getIndex() {
return PTFRollingPartition.this.numRowsProcessed;
}
@Override
public Object lead(int amt) throws HiveException {
int i = PTFRollingPartition.this.numRowsProcessed + amt;
i = i >= PTFRollingPartition.this.numRowsReceived ? PTFRollingPartition.this.numRowsReceived - 1
: i;
return PTFRollingPartition.this.getAt(i);
}
@Override
public Object lag(int amt) throws HiveException {
int i = PTFRollingPartition.this.numRowsProcessed - amt;
int start = PTFRollingPartition.this.numRowsReceived
- PTFRollingPartition.this.currWindow.size();
i = i < start ? start : i;
return PTFRollingPartition.this.getAt(i);
}
@Override
public Object resetToIndex(int idx) throws HiveException {
return PTFRollingPartition.this.getAt(idx);
}
@Override
public PTFPartition getPartition() {
return PTFRollingPartition.this;
}
@Override
public void reset() throws HiveException {
}
}
}