org.apache.hadoop.hive.serde2.columnar.BytesRefArrayWritable Maven / Gradle / Ivy
/*
* 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.serde2.columnar;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Arrays;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableFactories;
import org.apache.hadoop.io.WritableFactory;
/**
* BytesRefArrayWritable holds an array reference to BytesRefWritable,
* and is able to resize without recreating new array if not necessary.
*
*
* Each BytesRefArrayWritable holds instance has a valid field,
* which is the desired valid number of BytesRefWritable it holds.
* resetValid can reset the valid, but it will not care the underlying
* BytesRefWritable.
*/
public class BytesRefArrayWritable implements Writable,
Comparable {
private BytesRefWritable[] bytesRefWritables = null;
private int valid = 0;
/**
* Constructs an empty array with the specified capacity.
*
* @param capacity
* initial capacity
* @exception IllegalArgumentException
* if the specified initial capacity is negative
*/
public BytesRefArrayWritable(int capacity) {
if (capacity < 0) {
throw new IllegalArgumentException("Capacity can not be negative.");
}
bytesRefWritables = new BytesRefWritable[0];
ensureCapacity(capacity);
}
/**
* Constructs an empty array with a capacity of ten.
*/
public BytesRefArrayWritable() {
this(10);
}
/**
* Returns the number of valid elements.
*
* @return the number of valid elements
*/
public int size() {
return valid;
}
/**
* Gets the BytesRefWritable at the specified position. Make sure the position
* is valid by first call resetValid.
*
* @param index
* the position index, starting from zero
* @throws IndexOutOfBoundsException
*/
public BytesRefWritable get(int index) {
if (index >= valid) {
throw new IndexOutOfBoundsException(
"This BytesRefArrayWritable only has " + valid + " valid values.");
}
return bytesRefWritables[index];
}
/**
* Gets the BytesRefWritable at the specified position without checking.
*
* @param index
* the position index, starting from zero
* @throws IndexOutOfBoundsException
*/
public BytesRefWritable unCheckedGet(int index) {
return bytesRefWritables[index];
}
/**
* Set the BytesRefWritable at the specified position with the specified
* BytesRefWritable.
*
* @param index
* index position
* @param bytesRefWritable
* the new element
* @throws IllegalArgumentException
* if the specified new element is null
*/
public void set(int index, BytesRefWritable bytesRefWritable) {
ensureCapacity(index + 1);
bytesRefWritables[index] = bytesRefWritable;
if (valid <= index) {
valid = index + 1;
}
}
/**
* {@inheritDoc}
*/
@Override
public int compareTo(BytesRefArrayWritable other) {
if (other == null) {
throw new IllegalArgumentException("Argument can not be null.");
}
if (this == other) {
return 0;
}
int sizeDiff = valid - other.valid;
if (sizeDiff != 0) {
return sizeDiff;
}
for (int i = 0; i < valid; i++) {
int res = bytesRefWritables[i].compareTo(other.bytesRefWritables[i]);
if (res != 0) {
return res;
}
}
return 0;
}
/**
* {@inheritDoc}
*/
@Override
public boolean equals(Object o) {
if (o == null || !(o instanceof BytesRefArrayWritable)) {
return false;
}
return compareTo((BytesRefArrayWritable) o) == 0;
}
/**
* Removes all elements.
*/
public void clear() {
valid = 0;
}
/**
* enlarge the capacity if necessary, to ensure that it can hold the number of
* elements specified by newValidCapacity argument. It will also narrow the
* valid capacity when needed. Notice: it only enlarge or narrow the valid
* capacity with no care of the already stored invalid BytesRefWritable.
*
* @param newValidCapacity
* the desired capacity
*/
public void resetValid(int newValidCapacity) {
ensureCapacity(newValidCapacity);
valid = newValidCapacity;
}
protected void ensureCapacity(int newCapacity) {
int size = bytesRefWritables.length;
if (size < newCapacity) {
bytesRefWritables = Arrays.copyOf(bytesRefWritables, newCapacity);
while (size < newCapacity) {
bytesRefWritables[size] = new BytesRefWritable();
size++;
}
}
}
/**
* {@inheritDoc}
*/
@Override
public void readFields(DataInput in) throws IOException {
int count = in.readInt();
ensureCapacity(count);
for (int i = 0; i < count; i++) {
bytesRefWritables[i].readFields(in);
}
valid = count;
}
/**
* {@inheritDoc}
*/
@Override
public void write(DataOutput out) throws IOException {
out.writeInt(valid);
for (int i = 0; i < valid; i++) {
BytesRefWritable cu = bytesRefWritables[i];
cu.write(out);
}
}
static {
WritableFactories.setFactory(BytesRefArrayWritable.class,
new WritableFactory() {
@Override
public Writable newInstance() {
return new BytesRefArrayWritable();
}
});
}
}