org.opennms.netmgt.rrd
Interface RrdStrategy

All Known Implementing Classes:

QueuingRrdStrategy

public interface RrdStrategy

Defines an abstract strategy for manipulating round robin database file. This is used by the RrdUtils to implement the appropriate behaviour

Method Summary

void	closeFile(java.lang.Object rrd) This closes the supplied round robin database
java.lang.Object	createDefinition(java.lang.String creator, java.lang.String directory, java.lang.String rrdName, int step, java.util.List dataSources, java.util.List rraList) Create a round robin database definition from the supplied parameters.
void	createFile(java.lang.Object rrdDef) Creates the round robin database defined by the supplied definition.
java.io.InputStream	createGraph(java.lang.String command, java.io.File workDir) Creates an InputStream representing the bytes of a graph created from round robin data.
java.lang.Double	fetchLastValue(java.lang.String rrdFile, int interval) Fetches the last value from the round robin database with the given name.
java.lang.Double	fetchLastValueInRange(java.lang.String rrdFile, int interval, int range) Fetches the last value from the round robin database with the given name within a time range.
java.lang.String	getDefaultFileExtension() Get the file extension appropriate for files of this type
int	getGraphRightOffset() Returns the number of pixels that the right-hand side of the graph is offset from the right side of the created image.
int	getGraphTopOffsetWithText() Returns the number of pixels that the top of the graph is offset from the top of the created image if there is single line of header text.
java.lang.String	getStats() Provides the round robin database an opportunity to contribute statistics information to the logs file.
void	graphicsInitialize() This Initializes the graphics subsystem only.
void	initialize() Initialize the appropriate round robin system
java.lang.Object	openFile(java.lang.String fileName) Opens the round robin database with the supplied name.
void	updateFile(java.lang.Object rrd, java.lang.String owner, java.lang.String data) Updates the supplied round robin database with the given timestamp:value point

Method Detail

initialize

void initialize()
                throws java.lang.Exception

Initialize the appropriate round robin system

Throws:

java.lang.Exception - if an Error occurs

graphicsInitialize

void graphicsInitialize()
                        throws java.lang.Exception

This Initializes the graphics subsystem only. This is used by the web application to avoid the need for the JNI infrastructure in the webapp.

Throws:

java.lang.Exception

getDefaultFileExtension

java.lang.String getDefaultFileExtension()

Get the file extension appropriate for files of this type

createDefinition

java.lang.Object createDefinition(java.lang.String creator,
                                  java.lang.String directory,
                                  java.lang.String rrdName,
                                  int step,
                                  java.util.List dataSources,
                                  java.util.List rraList)
                                  throws java.lang.Exception

Create a round robin database definition from the supplied parameters. This definition is used in the createFile call to create the actual file.

Parameters:

creator - - A string representing who is creating this file for use in log msgs

directory - - The directory to create the file in

rrdName - - The name to use for the round robin database

step - - the step for the database

dataSources - - the datasources to use for round robin database

rraList - - a List of the round robin archives to create in the database

Returns:

an object representing the definition of an round robin database

Throws:

java.lang.Exception - If an error occurs while creating the definition

createFile

void createFile(java.lang.Object rrdDef)
                throws java.lang.Exception

Creates the round robin database defined by the supplied definition.

Parameters:

rrdDef - an round robin database definition created using the createDefinition call.

Throws:

java.lang.Exception - if an error occurs create the file

openFile

java.lang.Object openFile(java.lang.String fileName)
                          throws java.lang.Exception

Opens the round robin database with the supplied name. It is assumed the name refers to a round robin database appropriate for this strategy implementation

Parameters:

fileName - the name of the associated rrd file

Returns:

an open rrd reference that can by used in calls to updateFile and closeFile

Throws:

java.lang.Exception - if an error occurs opening the file

updateFile

void updateFile(java.lang.Object rrd,
                java.lang.String owner,
                java.lang.String data)
                throws java.lang.Exception

Updates the supplied round robin database with the given timestamp:value point

Parameters:

rrd - an rrd object created using openFile

owner - the owner of the rrd

data - a string of the form :

Throws:

java.lang.Exception - if an error occurs updating the file

closeFile

void closeFile(java.lang.Object rrd)
               throws java.lang.Exception

This closes the supplied round robin database

Parameters:

rrd - an rrd object created using openFile

Throws:

java.lang.Exception - if an error occurs closing the file

fetchLastValue

java.lang.Double fetchLastValue(java.lang.String rrdFile,
                                int interval)
                                throws java.lang.NumberFormatException,
                                       RrdException

Fetches the last value from the round robin database with the given name. The interval passed in should be the interval associated with the round robin database.

Parameters:

rrdFile - a name the represents a round robin database

interval - a step interval of the round robin database

Returns:

The last value as a Double (if the last value didn't exist returns a Double.NaN)

Throws:

java.lang.NumberFormatException

RrdException

fetchLastValueInRange

java.lang.Double fetchLastValueInRange(java.lang.String rrdFile,
                                       int interval,
                                       int range)
                                       throws java.lang.NumberFormatException,
                                              RrdException

Fetches the last value from the round robin database with the given name within a time range. The interval passed in should be the interval associated with the round robin database. The range should be the amount of "lag" acceptable for an update to be considered valid. Range must be a multiple of the RRD interval.

Parameters:

rrdFile - a name the represents a round robin database

interval - a step interval of the round robin database

range - an acceptable range for which the last value will be returned

Returns:

The last value as a Double (if the last value didn't exist returns a Double.NaN)

Throws:

java.lang.NumberFormatException

RrdException

createGraph

java.io.InputStream createGraph(java.lang.String command,
                                java.io.File workDir)
                                throws java.io.IOException,
                                       RrdException

Creates an InputStream representing the bytes of a graph created from round robin data. It accepts an rrdtool graph command. The underlying implementation converts this command to a format appropriate for it .

Parameters:

command - the command needed to create the graph

workDir - the directory that all referenced files are relative to

Returns:

an input stream representing the bytes of a graph image as a PNG file

Throws:

java.io.IOException - if an IOError occurs

RrdException - if an RRD error occurs

getGraphRightOffset

int getGraphRightOffset()

Returns the number of pixels that the right-hand side of the graph is offset from the right side of the created image. The offset should always be negative.

Returns:

offset in pixels. Should always be negative.

getGraphTopOffsetWithText

int getGraphTopOffsetWithText()

Returns the number of pixels that the top of the graph is offset from the top of the created image if there is single line of header text. The offset should always be negative.

Returns:

offset in pixels. Should always be negative.

getStats

java.lang.String getStats()

Provides the round robin database an opportunity to contribute statistics information to the logs file.

Returns:

a non-null string representing any staticstics to be included in the logs