org.apache.hadoop.hive.ql.metadata.Sample 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.ql.metadata;
/**
* A sample defines a subset of data based on sampling on a given dimension.
*
**/
public class Sample {
protected int sampleNum;
protected int sampleFraction;
protected Dimension sampleDimension;
protected int moduloNum;
@SuppressWarnings("nls")
public Sample(int num, int fraction, Dimension d) throws HiveException {
if ((num <= 0) || (num > fraction)) {
throw new HiveException("Bad sample spec: " + num + "/" + fraction);
}
sampleNum = num;
moduloNum = sampleNum - 1;
sampleFraction = fraction;
sampleDimension = d;
}
/**
* Given an arbitrary object, determine if it falls within this sample.
*/
public boolean inSample(Object o) {
return (((sampleDimension.hashCode(o) & Integer.MAX_VALUE) % sampleFraction) == moduloNum);
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null) {
return false;
}
if (o instanceof Sample) {
Sample s = (Sample) o;
return ((sampleNum == s.sampleNum)
&& (sampleFraction == s.sampleFraction) && sampleDimension
.equals(s.sampleDimension));
}
return (false);
}
public int getSampleNum() {
return sampleNum;
}
public int getSampleFraction() {
return sampleFraction;
}
public Dimension getSampleDimension() {
return sampleDimension;
}
@SuppressWarnings("nls")
@Override
public String toString() {
return sampleNum + "/" + sampleFraction + "@(" + sampleDimension + ")";
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result
+ ((sampleDimension == null) ? 0 : sampleDimension.hashCode());
result = prime * result + sampleFraction;
result = prime * result + sampleNum;
return result;
}
}