| /* |
| * 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.data; |
| |
| import java.io.DataInput; |
| import java.io.DataOutput; |
| import java.io.IOException; |
| import java.util.Iterator; |
| |
| import org.apache.pig.PigException; |
| import org.apache.pig.backend.executionengine.ExecException; |
| |
| /** |
| * A simple performant implementation of the DataBag |
| * interface which only holds a single tuple. This will |
| * be used from POPreCombinerLocalRearrange and wherever else |
| * a single Tuple non-serializable DataBag is required. |
| */ |
| public class SingleTupleBag implements DataBag { |
| |
| private static final long serialVersionUID = 1L; |
| Tuple item; |
| |
| public SingleTupleBag(Tuple t) { |
| item = t; |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.pig.data.DataBag#add(org.apache.pig.data.Tuple) |
| * NOTE: It is the user's responsibility to ensure only a single |
| * Tuple is ever added into a SingleTupleBag |
| */ |
| @Override |
| public void add(Tuple t) { |
| item = t; |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.pig.data.DataBag#addAll(org.apache.pig.data.DataBag) |
| */ |
| @Override |
| public void addAll(DataBag b) { |
| throw new RuntimeException("Cannot create SingleTupleBag from another DataBag"); |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.pig.data.DataBag#clear() |
| */ |
| @Override |
| public void clear() { |
| throw new RuntimeException("Cannot clear SingleTupleBag"); |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.pig.data.DataBag#isDistinct() |
| */ |
| @Override |
| public boolean isDistinct() { |
| return false; |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.pig.data.DataBag#isSorted() |
| */ |
| @Override |
| public boolean isSorted() { |
| return false; |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.pig.data.DataBag#iterator() |
| */ |
| @Override |
| public Iterator<Tuple> iterator() { |
| return new TBIterator(); |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.pig.data.DataBag#markStale(boolean) |
| */ |
| @Override |
| public void markStale(boolean stale) { |
| throw new RuntimeException("SingleTupleBag cannot be marked stale"); |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.pig.data.DataBag#size() |
| */ |
| @Override |
| public long size() { |
| return 1; |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.pig.impl.util.Spillable#getMemorySize() |
| */ |
| @Override |
| public long getMemorySize() { |
| return 0; |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.pig.impl.util.Spillable#spill() |
| */ |
| @Override |
| public long spill() { |
| return 0; |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.hadoop.io.Writable#readFields(java.io.DataInput) |
| */ |
| @Override |
| public void readFields(DataInput in) throws IOException { |
| long size = in.readLong(); |
| |
| for (long i = 0; i < size; i++) { |
| try { |
| Object o = DataReaderWriter.readDatum(in); |
| add((Tuple)o); |
| } catch (ExecException ee) { |
| throw ee; |
| } |
| } |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.hadoop.io.Writable#write(java.io.DataOutput) |
| */ |
| @Override |
| public void write(DataOutput out) throws IOException { |
| out.writeLong(size()); |
| Iterator<Tuple> it = iterator(); |
| while (it.hasNext()) { |
| Tuple item = it.next(); |
| item.write(out); |
| } |
| } |
| |
| /* (non-Javadoc) |
| * @see java.lang.Comparable#compareTo(java.lang.Object) |
| */ |
| @Override |
| public int compareTo(Object o) { |
| // TODO Auto-generated method stub |
| return 0; |
| } |
| |
| public boolean equals(Object o){ |
| // TODO: match to compareTo if it is updated |
| return true; |
| } |
| |
| public int hashCode() { |
| return 42; |
| } |
| |
| class TBIterator implements Iterator<Tuple> { |
| boolean nextDone = false; |
| /* (non-Javadoc) |
| * @see java.util.Iterator#hasNext() |
| */ |
| @Override |
| public boolean hasNext() { |
| return !nextDone; |
| } |
| |
| /* (non-Javadoc) |
| * @see java.util.Iterator#next() |
| */ |
| @Override |
| public Tuple next() { |
| nextDone = true; |
| return item; |
| |
| } |
| |
| /* (non-Javadoc) |
| * @see java.util.Iterator#remove() |
| */ |
| @Override |
| public void remove() { |
| throw new RuntimeException("SingleTupleBag.iterator().remove() is not allowed"); |
| } |
| } |
| |
| /** |
| * Write the bag into a string. */ |
| @Override |
| public String toString() { |
| return "{" + item + "}"; |
| } |
| } |