AvgValue.java revision 91cfa10a8e55050a5103c4b2e83b0bf8d783a7cb
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2007 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*
* ident "%Z%%M% %I% %E% SMI"
*/
package org.opensolaris.os.dtrace;
import java.io.*;
import java.beans.*;
/**
* A {@code long} value aggregated by the DTrace {@code avg()} action.
* <p>
* Immutable. Supports persistence using {@link java.beans.XMLEncoder}.
*
* @see Aggregation
* @author Tom Erickson
*/
public final class AvgValue extends AbstractAggregationValue {
static final long serialVersionUID = 1633169020110237906L;
/** @serial */
private final long total;
/** @serial */
private final long count;
static {
try {
BeanInfo info = Introspector.getBeanInfo(AvgValue.class);
PersistenceDelegate persistenceDelegate =
new DefaultPersistenceDelegate(
new String[] {"value", "total", "count"});
BeanDescriptor d = info.getBeanDescriptor();
d.setValue("persistenceDelegate", persistenceDelegate);
} catch (IntrospectionException e) {
System.out.println(e);
}
}
/**
* Creates a value aggregated by the DTrace {@code avg()} action.
* Supports XML persistence.
*
* @param v average
* @param averagedTotal sum total of all values averaged
* @param averagedValueCount number of values averaged
* @throws IllegalArgumentException if the given count is negative
* or if the given average is not the value expected for the given
* total and count
*/
public
AvgValue(long v, long averagedTotal, long averagedValueCount)
{
super(v);
total = averagedTotal;
count = averagedValueCount;
validate();
}
private final void
validate()
{
if (count < 0) {
throw new IllegalArgumentException("count is negative");
}
long average = super.getValue().longValue();
if (count == 0) {
if (average != 0) {
throw new IllegalArgumentException(
"count of values is zero, average is non-zero (" +
average + ")");
}
} else {
if (average != (total / count)) {
throw new IllegalArgumentException(
getValue().toString() + " is not the expected " +
"average of total " + total + " and count " +
count);
}
}
}
// Needed to support XML persistence since XMLDecoder cannot find
// the public method of the non-public superclass.
/**
* Gets the average of the aggregated values.
*
* @return average of the aggregated values, equal to <code>({@link
* #getTotal()} / {@link #getCount()})</code> rounded down
*/
public Long
getValue()
{
return (Long)super.getValue();
}
/**
* Gets the sum total of the aggregated values.
*
* @return the sum total of the aggregated values
*/
public long
getTotal()
{
return total;
}
/**
* Gets the number of aggregated values included in the average.
*
* @return the number of aggregated values included in the average
*/
public long
getCount()
{
return count;
}
private void
readObject(ObjectInputStream s)
throws IOException, ClassNotFoundException
{
s.defaultReadObject();
// check invariants
try {
validate();
} catch (Exception e) {
throw new InvalidObjectException(e.getMessage());
}
}
}