org.apache.solr.client.solrj.io.stream.metrics.MeanMetric 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.solr.client.solrj.io.stream.metrics;
import java.io.IOException;
import java.util.Locale;
import org.apache.solr.client.solrj.io.Tuple;
import org.apache.solr.client.solrj.io.stream.expr.StreamExpression;
import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionParameter;
import org.apache.solr.client.solrj.io.stream.expr.StreamFactory;
public class MeanMetric extends Metric {
// How'd the MeanMetric get to be so mean?
// Maybe it was born with it.
// Maybe it was mayba-mean.
//
// I'll see myself out.
private String columnName;
private double doubleSum;
private long longSum;
private long count;
public MeanMetric(String columnName){
init("avg", columnName);
}
public MeanMetric(StreamExpression expression, StreamFactory factory) throws IOException{
// grab all parameters out
String functionName = expression.getFunctionName();
String columnName = factory.getValueOperand(expression, 0);
// validate expression contains only what we want.
if(null == columnName){
throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - expected %s(columnName)", expression, functionName));
}
if(1 != expression.getParameters().size()){
throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - unknown operands found", expression));
}
init(functionName, columnName);
}
private void init(String functionName, String columnName){
this.columnName = columnName;
setFunctionName(functionName);
setIdentifier(functionName, "(", columnName, ")");
}
public void update(Tuple tuple) {
++count;
Object o = tuple.get(columnName);
if(o instanceof Double) {
Double d = (Double)tuple.get(columnName);
doubleSum += d;
} else {
Long l = (Long)tuple.get(columnName);
longSum += l;
}
}
public Metric newInstance() {
return new MeanMetric(columnName);
}
public String[] getColumns() {
return new String[]{columnName};
}
public Double getValue() {
double dcount = (double)count;
if(longSum == 0) {
return doubleSum/dcount;
} else {
return longSum/dcount;
}
}
@Override
public StreamExpressionParameter toExpression(StreamFactory factory) throws IOException {
return new StreamExpression(getFunctionName()).withParameter(columnName);
}
}