package org.rrd4j.core;
import java.io.IOException;
/**
* Class to represent RRD header. Header information is mainly static (once set, it
* cannot be changed), with the exception of last update time (this value is changed whenever
* RRD gets updated).
* <p>
*
* Normally, you don't need to manipulate the Header object directly - Rrd4j framework
* does it for you.
* <p>
*
* @author Sasa Markovic*
*/
public class Header implements RrdUpdater {
static final int SIGNATURE_LENGTH = 5;
static final String SIGNATURE = "RRD4J";
static final String DEFAULT_SIGNATURE = "RRD4J, version 0.1";
static final String RRDTOOL_VERSION1 = "0001";
static final String RRDTOOL_VERSION3 = "0003";
private static final String VERSIONS[] = {"version 0.1", "version 0.2"};
private RrdDb parentDb;
private int version = -1;
private RrdString signature;
private RrdLong step;
private RrdInt dsCount, arcCount;
private RrdLong lastUpdateTime;
Header(RrdDb parentDb, RrdDef rrdDef) throws IOException {
this.parentDb = parentDb;
String initSignature = null;
if(rrdDef != null) {
version = rrdDef.getVersion();
initSignature = SIGNATURE + ", " + VERSIONS[ version - 1];
}
else {
initSignature = DEFAULT_SIGNATURE;
}
signature = new RrdString(this); // NOT constant, may be cached
step = new RrdLong(this, true); // constant, may be cached
dsCount = new RrdInt(this, true); // constant, may be cached
arcCount = new RrdInt(this, true); // constant, may be cached
lastUpdateTime = new RrdLong(this);
if (rrdDef != null) {
signature.set(initSignature);
step.set(rrdDef.getStep());
dsCount.set(rrdDef.getDsCount());
arcCount.set(rrdDef.getArcCount());
lastUpdateTime.set(rrdDef.getStartTime());
}
}
Header(RrdDb parentDb, DataImporter reader) throws IOException {
this(parentDb, (RrdDef) null);
String version = reader.getVersion();
if (!RRDTOOL_VERSION1.equals(version) && !RRDTOOL_VERSION3.equals(version) ) {
throw new IllegalArgumentException("Could not unserialize xml version " + version);
}
signature.set(DEFAULT_SIGNATURE);
step.set(reader.getStep());
dsCount.set(reader.getDsCount());
arcCount.set(reader.getArcCount());
lastUpdateTime.set(reader.getLastUpdateTime());
}
/**
* Returns RRD signature. Initially, the returned string will be
* of the form <b><i>Rrd4j, version x.x</i></b>.
*
* @return RRD signature
* @throws java.io.IOException Thrown in case of I/O error
*/
public String getSignature() throws IOException {
return signature.get();
}
/**
* <p>getInfo.</p>
*
* @return a {@link java.lang.String} object.
* @throws java.io.IOException if any.
*/
public String getInfo() throws IOException {
return getSignature().substring(SIGNATURE_LENGTH);
}
/**
* <p>setInfo.</p>
*
* @param info a {@link java.lang.String} object.
* @throws java.io.IOException if any.
*/
public void setInfo(String info) throws IOException {
if (info != null && info.length() > 0) {
signature.set(SIGNATURE + info);
}
else {
signature.set(SIGNATURE);
}
}
/**
* Returns the last update time of the RRD.
*
* @return Timestamp (Unix epoch, no milliseconds) corresponding to the last update time.
* @throws java.io.IOException Thrown in case of I/O error
*/
public long getLastUpdateTime() throws IOException {
return lastUpdateTime.get();
}
/**
* Returns primary RRD time step.
*
* @return Primary time step in seconds
* @throws java.io.IOException Thrown in case of I/O error
*/
public long getStep() throws IOException {
return step.get();
}
/**
* Returns the number of datasources defined in the RRD.
*
* @return Number of datasources defined
* @throws java.io.IOException Thrown in case of I/O error
*/
public int getDsCount() throws IOException {
return dsCount.get();
}
/**
* Returns the number of archives defined in the RRD.
*
* @return Number of archives defined
* @throws java.io.IOException Thrown in case of I/O error
*/
public int getArcCount() throws IOException {
return arcCount.get();
}
void setLastUpdateTime(long lastUpdateTime) throws IOException {
this.lastUpdateTime.set(lastUpdateTime);
}
String dump() throws IOException {
return "== HEADER ==\n" +
"signature:" + getSignature() +
" lastUpdateTime:" + getLastUpdateTime() +
" step:" + getStep() +
" dsCount:" + getDsCount() +
" arcCount:" + getArcCount() + "\n";
}
void appendXml(XmlWriter writer) throws IOException {
writer.writeComment(signature.get());
writer.writeTag("version", RRDTOOL_VERSION3);
writer.writeComment("Seconds");
writer.writeTag("step", step.get());
writer.writeComment(Util.getDate(lastUpdateTime.get()));
writer.writeTag("lastupdate", lastUpdateTime.get());
}
/**
* {@inheritDoc}
*
* Copies object's internal state to another Header object.
*/
public void copyStateTo(RrdUpdater other) throws IOException {
if (!(other instanceof Header)) {
throw new IllegalArgumentException(
"Cannot copy Header object to " + other.getClass().getName());
}
Header header = (Header) other;
//header.signature.set(signature.get());
header.lastUpdateTime.set(lastUpdateTime.get());
}
/**
* Returns the underlying storage (backend) object which actually performs all
* I/O operations.
*
* @return I/O backend object
*/
public RrdBackend getRrdBackend() {
return parentDb.getRrdBackend();
}
/**
* Return the RRD version.
*
* @return RRD version
* @throws java.io.IOException if any.
*/
public int getVersion() throws IOException {
if(version < 0) {
for(int i=0; i < VERSIONS.length; i++) {
if(signature.get().endsWith(VERSIONS[i])) {
version = i + 1;
break;
}
}
}
return version;
}
boolean isRrd4jHeader() throws IOException {
return signature.get().startsWith(SIGNATURE) || signature.get().startsWith("JR"); // backwards compatible with JRobin
}
void validateHeader() throws IOException {
if (!isRrd4jHeader()) {
throw new IOException("Invalid file header. File [" + parentDb.getCanonicalPath() + "] is not a RRD4J RRD file");
}
}
/**
* Required to implement RrdUpdater interface. You should never call this method directly.
*
* @return Allocator object
*/
public RrdAllocator getRrdAllocator() {
return parentDb.getRrdAllocator();
}
}