Package org.rrd4j.core

Class Header

java.lang.Object

org.rrd4j.core.Header

All Implemented Interfaces:

RrdUpdater<Header>

public class Header
extends Object
implements RrdUpdater<Header>

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).

Normally, you don't need to manipulate the Header object directly - Rrd4j framework does it for you.

Author:

Sasa Markovic*

Field Summary

Fields

Modifier and Type	Field	Description
(package private) static final String	DEFAULT_SIGNATURE
(package private) static final String	RRDTOOL_VERSION1
(package private) static final String	RRDTOOL_VERSION3
(package private) static final String	SIGNATURE
(package private) static final int	SIGNATURE_LENGTH

Constructor Summary

Constructors

Constructor	Description
Header(RrdDb parentDb, DataImporter reader)
Header(RrdDb parentDb, RrdDef rrdDef)

Method Summary

Modifier and Type	Method	Description
(package private) void	appendXml(XmlWriter writer)
void	copyStateTo(Header header)	copyStateTo.
(package private) String	dump()
int	getArcCount()	Returns the number of archives defined in the RRD.
int	getDsCount()	Returns the number of datasources defined in the RRD.
String	getInfo()	getInfo.
long	getLastUpdateTime()	Returns the last update time of the RRD.
RrdAllocator	getRrdAllocator()	Required to implement RrdUpdater interface.
RrdBackend	getRrdBackend()	Returns the underlying storage (backend) object which actually performs all I/O operations.
String	getSignature()	Returns RRD signature.
long	getStep()	Returns primary RRD time step.
int	getVersion()	Return the RRD version.
(package private) boolean	isRrd4jHeader()
void	setInfo(String info)	setInfo.
(package private) void	setLastUpdateTime(long lastUpdateTime)
(package private) void	validateHeader()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

SIGNATURE_LENGTH

static final int SIGNATURE_LENGTH

See Also:

• Constant Field Values

SIGNATURE

static final String SIGNATURE

See Also:

• Constant Field Values

DEFAULT_SIGNATURE

static final String DEFAULT_SIGNATURE

See Also:

• Constant Field Values

RRDTOOL_VERSION1

static final String RRDTOOL_VERSION1

See Also:

• Constant Field Values

RRDTOOL_VERSION3

static final String RRDTOOL_VERSION3

See Also:

• Constant Field Values

Constructor Details

Header

Header(RrdDb parentDb,
 RrdDef rrdDef)
throws IOException

Throws:

IOException

Header

Header(RrdDb parentDb,
 DataImporter reader)
throws IOException

Throws:

IOException

Method Details

getSignature

public String getSignature()
                    throws IOException

Returns RRD signature. Initially, the returned string will be of the form Rrd4j, version x.x.

Returns:

RRD signature

Throws:

IOException - Thrown in case of I/O error

getInfo

public String getInfo()
               throws IOException

getInfo.

Returns:

a String object.

Throws:

IOException - if any.

setInfo

public void setInfo(String info)
             throws IOException

setInfo.

Parameters:

info - a String object.

Throws:

IOException - if any.

getLastUpdateTime

public long getLastUpdateTime()
                       throws IOException

Returns the last update time of the RRD.

Returns:

Timestamp (Unix epoch, no milliseconds) corresponding to the last update time.

Throws:

IOException - Thrown in case of I/O error

getStep

public long getStep()
             throws IOException

Returns primary RRD time step.

Returns:

Primary time step in seconds

Throws:

IOException - Thrown in case of I/O error

getDsCount

public int getDsCount()
               throws IOException

Returns the number of datasources defined in the RRD.

Returns:

Number of datasources defined

Throws:

IOException - Thrown in case of I/O error

getArcCount

public int getArcCount()
                throws IOException

Returns the number of archives defined in the RRD.

Returns:

Number of archives defined

Throws:

IOException - Thrown in case of I/O error

setLastUpdateTime

void setLastUpdateTime(long lastUpdateTime)
                throws IOException

Throws:

IOException

dump

String dump()
     throws IOException

Throws:

IOException

appendXml

void appendXml(XmlWriter writer)
        throws IOException

Throws:

IOException

copyStateTo

public void copyStateTo(Header header)
                 throws IOException

copyStateTo.

Copies object's internal state to another Header object.

Specified by:

copyStateTo in interface RrdUpdater<Header>

Parameters:

header - a RrdUpdater object.

Throws:

IOException - if any.

getRrdBackend

public RrdBackend getRrdBackend()

Returns the underlying storage (backend) object which actually performs all I/O operations.

Specified by:

getRrdBackend in interface RrdUpdater<Header>

Returns:

I/O backend object

getVersion

public int getVersion()
               throws IOException

Return the RRD version.

Returns:

RRD version

Throws:

IOException - if any.

isRrd4jHeader

boolean isRrd4jHeader()

validateHeader

void validateHeader()
             throws IOException

Throws:

IOException

getRrdAllocator

public RrdAllocator getRrdAllocator()

Required to implement RrdUpdater interface. You should never call this method directly.

Specified by:

getRrdAllocator in interface RrdUpdater<Header>

Returns:

Allocator object