package org.rrd4j.core;
import java.io.IOException;
/**
* Class to represent internal RRD archive state for a single datasource. Objects of this
* class are never manipulated directly, it's up to Rrd4j to manage internal archive states.
*
* @author Sasa Markovic
*/
public class ArcState implements RrdUpdater {
private Archive parentArc;
private RrdDouble accumValue;
private RrdLong nanSteps;
ArcState(Archive parentArc, boolean shouldInitialize) throws IOException {
this.parentArc = parentArc;
accumValue = new RrdDouble(this);
nanSteps = new RrdLong(this);
if (shouldInitialize) {
Header header = parentArc.getParentDb().getHeader();
long step = header.getStep();
long lastUpdateTime = header.getLastUpdateTime();
long arcStep = parentArc.getArcStep();
long initNanSteps = (Util.normalize(lastUpdateTime, step) -
Util.normalize(lastUpdateTime, arcStep)) / step;
accumValue.set(Double.NaN);
nanSteps.set(initNanSteps);
}
}
String dump() throws IOException {
return "accumValue:" + accumValue.get() + " nanSteps:" + nanSteps.get() + "\n";
}
void setNanSteps(long value) throws IOException {
nanSteps.set(value);
}
/**
* Returns the number of currently accumulated NaN steps.
*
* @return Number of currently accumulated NaN steps.
* @throws java.io.IOException Thrown in case of I/O error
*/
public long getNanSteps() throws IOException {
return nanSteps.get();
}
void setAccumValue(double value) throws IOException {
accumValue.set(value);
}
/**
* Returns the value accumulated so far.
*
* @return Accumulated value
* @throws java.io.IOException Thrown in case of I/O error
*/
public double getAccumValue() throws IOException {
return accumValue.get();
}
/**
* Returns the Archive object to which this ArcState object belongs.
*
* @return Parent Archive object.
*/
public Archive getParent() {
return parentArc;
}
void appendXml(XmlWriter writer) throws IOException {
writer.startTag("ds");
writer.writeTag("value", accumValue.get());
writer.writeTag("unknown_datapoints", nanSteps.get());
writer.closeTag(); // ds
}
/**
* {@inheritDoc}
*
* Copies object's internal state to another ArcState object.
*/
public void copyStateTo(RrdUpdater other) throws IOException {
if (!(other instanceof ArcState)) {
throw new IllegalArgumentException("Cannot copy ArcState object to " + other.getClass().getName());
}
ArcState arcState = (ArcState) other;
arcState.accumValue.set(accumValue.get());
arcState.nanSteps.set(nanSteps.get());
}
/**
* Returns the underlying storage (backend) object which actually performs all
* I/O operations.
*
* @return I/O backend object
*/
public RrdBackend getRrdBackend() {
return parentArc.getRrdBackend();
}
/**
* Required to implement RrdUpdater interface. You should never call this method directly.
*
* @return Allocator object
*/
public RrdAllocator getRrdAllocator() {
return parentArc.getRrdAllocator();
}
}