Package org.epics.archiverappliance.config

Class ConvertPVNameToKey

java.lang.Object

org.epics.archiverappliance.config.ConvertPVNameToKey

All Implemented Interfaces:

PVNameToKeyMapping

public class ConvertPVNameToKey
extends Object
implements PVNameToKeyMapping

Most labs use a standard character (typically the ":" or the "-" character) in their naming conventions to separate out the components of a name. We want to replace these characters with the File.separator so that the key/file structure reflects the naming convention reasonably closely This give us 2 things

1. All the files/keys for the entire archiver system do not land in the same folder. This improves performance significantly on ext2/3/4 like filesystems which can handle upto around 10000 files in a folder reasonably well but are very inefficient if this limit is crossed. Note, systems like ZFS/BTRFS do not have this limitation.
2. We have a deterministic way to go from PV name to key/file name

One other issue we need to solve is that some PV's (X:CTRD_V) are substrings of other PV's (X:CTRD_V_BOOK). So, files for X:CTRD_V are matches for X:CTRD_V_BOOK as well. We can either replace the underscores with /'s as well. Or the character that separates the final name component of the PV name from the rest of the file name (time partition info, extension etc) should also be something that would not show up in a PV name at the end. For now, we choose the latter and use another property to identify the separator string (for example ":") as the terminator. For example, X:CTRD_V_BOOK is mapped to X/CTRD_V_BOOK:.

This class uses two properties obtained from the archappl.properties file to map PV names to keys.

1. org.epics.archiverappliance.config.ConvertPVNameToKey.siteNameSpaceSeparators - This is a list of characters that separate the components of the PV name. The syntax for this must satisfy Java's replaceAll regex requirements. So to specify a list containing the ":" and the "-" characters, we have to use [\\:\\-]
2. org.epics.archiverappliance.config.ConvertPVNameToKey.siteNameSpaceTerminator - This is the character used as the terminator of the PV name portion of the key.

Author:

mshankar

Constructor Summary

Constructors

Constructor	Description
ConvertPVNameToKey()

Method Summary

Modifier and Type	Method	Description
String[]	breakIntoParts(String pvName)	Break a PV name into parts separated by the site specific separators For examples, ABC:123:DEF gets broken into [ABC, 123, DEF]
String	convertPVNameToKey(String pvName)
protected String	generateChunkKey(String pvName)	One option is to simply override the final element of chunk key generation.
void	initialize(ConfigService configService)
PVNameToKeyMapping	overrideTerminator(char terminator)

Methods inherited from class java.lang.Object

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

Constructor Details

ConvertPVNameToKey

public ConvertPVNameToKey()

Method Details

convertPVNameToKey

public String convertPVNameToKey(String pvName)

Specified by:

convertPVNameToKey in interface PVNameToKeyMapping

initialize

public void initialize(ConfigService configService)
                throws ConfigException

Specified by:

initialize in interface PVNameToKeyMapping

Throws:

ConfigException

generateChunkKey

protected String generateChunkKey(String pvName)

One option is to simply override the final element of chunk key generation. To do that, subclass and override this method. (Of course, you still have to register the subclass in archappl.properties).

Parameters:

pvName - The name of PV.

Returns:

pvName  

breakIntoParts

public String[] breakIntoParts(String pvName)

Description copied from interface: PVNameToKeyMapping

Break a PV name into parts separated by the site specific separators For examples, ABC:123:DEF gets broken into [ABC, 123, DEF]

Specified by:

breakIntoParts in interface PVNameToKeyMapping

Parameters:

pvName - The name of PV.

Returns:

String Parts separated by separators

overrideTerminator

public PVNameToKeyMapping overrideTerminator(char terminator)

Specified by:

overrideTerminator in interface PVNameToKeyMapping