/*******************************************************************************
* Copyright (c) 2001-2005 Sasa Markovic and Ciaran Treanor.
* Copyright (c) 2011 The OpenNMS Group, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*******************************************************************************/
package org.jrobin.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 - JRobin framework
* does it for you.
*
* @author <a href="mailto:saxon@jrobin.org">Sasa Markovic</a>*
*/
public class Header implements RrdUpdater {
static final int SIGNATURE_LENGTH = 2;
static final String SIGNATURE = "JR";
static final String DEFAULT_SIGNATURE = "JRobin, version 0.1";
static final String RRDTOOL_VERSION = "0001";
private RrdDb parentDb;
private RrdString signature;
private RrdLong step;
private RrdInt dsCount, arcCount;
private RrdLong lastUpdateTime;
private Long m_primitiveStep = null;
private Integer m_primitiveDsCount = null;
private Integer m_primitiveArcCount = null;
Header(final RrdDb parentDb, final RrdDef rrdDef) throws IOException {
final boolean shouldInitialize = rrdDef != null;
this.parentDb = parentDb;
signature = new RrdString(this); // NOT constant, may NOT 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 (shouldInitialize) {
signature.set(DEFAULT_SIGNATURE);
step.set(rrdDef.getStep());
dsCount.set(rrdDef.getDsCount());
arcCount.set(rrdDef.getArcCount());
lastUpdateTime.set(rrdDef.getStartTime());
}
}
Header(final RrdDb parentDb, final DataImporter reader) throws IOException, RrdException {
this(parentDb, (RrdDef) null);
final String version = reader.getVersion();
final int intVersion = Integer.parseInt(version);
if (intVersion > 3) {
throw new RrdException("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>JRobin, version x.x</i></b>. Note: RRD format did not
* change since Jrobin 1.0.0 release (and probably never will).
*
* @return RRD signature
* @throws IOException Thrown in case of I/O error
*/
public String getSignature() throws IOException {
return signature.get();
}
public String getInfo() throws IOException {
return getSignature().substring(SIGNATURE_LENGTH);
}
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 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 IOException Thrown in case of I/O error
*/
public long getStep() throws IOException {
if (m_primitiveStep == null) {
m_primitiveStep = step.get();
}
return m_primitiveStep;
}
/**
* Returns the number of datasources defined in the RRD.
*
* @return Number of datasources defined
* @throws IOException Thrown in case of I/O error
*/
public int getDsCount() throws IOException {
if (m_primitiveDsCount == null) {
m_primitiveDsCount = dsCount.get();
}
return m_primitiveDsCount;
}
/**
* Returns the number of archives defined in the RRD.
*
* @return Number of archives defined
* @throws IOException Thrown in case of I/O error
*/
public int getArcCount() throws IOException {
if (m_primitiveArcCount == null) {
m_primitiveArcCount = arcCount.get();
}
return m_primitiveArcCount;
}
public void setLastUpdateTime(final 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_VERSION);
writer.writeComment("Seconds");
writer.writeTag("step", step.get());
writer.writeComment(Util.getDate(lastUpdateTime.get()));
writer.writeTag("lastupdate", lastUpdateTime.get());
}
/**
* Copies object's internal state to another Header object.
*
* @param other New Header object to copy state to
* @throws IOException Thrown in case of I/O error
* @throws RrdException Thrown if supplied argument is not a Header object
*/
public void copyStateTo(final RrdUpdater other) throws IOException, RrdException {
if (!(other instanceof Header)) {
throw new RrdException( "Cannot copy Header object to " + other.getClass().getName());
}
final 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();
}
boolean isJRobinHeader() throws IOException {
return signature.get().startsWith(SIGNATURE);
}
void validateHeader() throws IOException, RrdException {
if (!isJRobinHeader()) {
throw new RrdException("Invalid file header. File [" + parentDb.getCanonicalPath() + "] is not a JRobin RRD file");
}
}
/**
* Required to implement RrdUpdater interface. You should never call this method directly.
*
* @return Allocator object
*/
public RrdAllocator getRrdAllocator() {
return parentDb.getRrdAllocator();
}
}