thredds.inventory

Interface CollectionManager

All Superinterfaces:

AutoCloseable, CollectionUpdateListener, MCollection

All Known Implementing Classes:

CollectionManagerAbstract, CollectionManagerCatalog, MFileCollectionManager

public interface CollectionManager
extends MCollection, CollectionUpdateListener

Manages a dynamic collection of MFile objects. You must call scan() first. This is the older stuff used by FMRC. GRIB uses lighter weight MCollection. An MFile must have the property that

  NetcdfDataset.open(MFile.getPath, ...); 

should work.

A CollectionManager implements the element.

collection element

A collection element defines the collection of datasets.

<collection spec="/data/ldm/pub/native/satellite/3.9/WEST-CONUS_4km/WEST-CONUS_4km_3.9_#yyyyMMdd_HHmm#.gini$"
            name="WEST-CONUS_4km" olderThan="1 min" olderThan="15 min" />

The XML Schema:

<xsd:complexType name="collectionType">
  1)  <xsd:attribute name="spec" type="xsd:string" use="required"/>
  2)  <xsd:attribute name="name" type="xsd:token"/>
  3)  <xsd:attribute name="olderThan" type="xsd:string" />
  5)  <xsd:attribute name="dateFormatMark" type="xsd:string"/>
  6)  <xsd:attribute name="timePartition" type="xsd:string"/>
</xsd:complexType>

where

1. spec: collection specification string (required).
2. name: collection name must be unique in all of your TDS catalogs. This is used for external triggers and as an easy to read identifier for indexing, logging and debugging. If missing, the spec string is used (not a good idea in the context of the TDS).
3. olderThan (optional): Only files whose lastModified date is older than this are included. This excludes files that are in the process of being written. However, it only applies to newly found files, that is, once a file is in the collection it is not removed because it got updated.
4. dateFormatMark (optional): the collection specification string can only extract dates from the file name, as opposed to the file path, which includes all of the parent directory names. Use the dateFormatMark in order to extract the date from the full path. Use this OR a date extrator in the specification string, but not both.
5. timePartition (optional):: experimental, not complete yet.

Since:

Jan 19, 2010

Author:

caron

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	CollectionManager.ChangeChecker
static class	CollectionManager.TriggerEvent
static interface	CollectionManager.TriggerListener A TriggerEvent.proto is sent if protoDataset.change = "cron" has been specified A TriggerEvent.update is sent if a scan has happened and a change in the list of MFiles has occurred, or an MFile has been updated

Method Summary

Methods

Modifier and Type	Method and Description
void	addEventListener(CollectionManager.TriggerListener l) Register to get Trigger events
long	getLastChanged() Get the last time the collection changed
long	getLastScanned() Get the last time scanned
TimeDuration	getRecheck() Get how often to rescan
boolean	isScanNeeded() Compute whether rescan is needed, based on getRecheck(), and the LastScanned value.
boolean	isStatic() static means doesnt need to be monitored for changes; can be externally triggered, or read in at startup.
void	removeEventListener(CollectionManager.TriggerListener l)
boolean	scan(boolean sendEvent) Scan the collection.
boolean	scanIfNeeded() If isScanNeeded(), do a scan.

Methods inherited from interface thredds.inventory.MCollection

close, extractDate, getAuxInfo, getCollectionName, getFileIterator, getFilenames, getFilesSorted, getIndexFilename, getLastModified, getLatestFile, getPartitionDate, getProtoIndex, getRoot, hasDateExtractor, putAuxInfo

Methods inherited from interface thredds.inventory.CollectionUpdateListener

getCollectionName, sendEvent

Method Detail

isStatic

boolean isStatic()

static means doesnt need to be monitored for changes; can be externally triggered, or read in at startup. true if no recheckAfter and no update.rescan

Returns:

if static

getLastScanned

long getLastScanned()

Get the last time scanned

Returns:

msecs since 1970

getLastChanged

long getLastChanged()

Get the last time the collection changed

Returns:

msecs since 1970

getRecheck

TimeDuration getRecheck()

Get how often to rescan

Returns:

time duration of rescan period, or null if none.

isScanNeeded

boolean isScanNeeded()

Compute whether rescan is needed, based on getRecheck(), and the LastScanned value.

Returns:

true if rescan is needed.

scanIfNeeded

boolean scanIfNeeded()
                     throws IOException

If isScanNeeded(), do a scan. Do not send an event.

Returns:

true if scan was done, and anything changed.

Throws:

IOException - on io error

scan

boolean scan(boolean sendEvent)
             throws IOException

Scan the collection. Files may have been deleted or added since last time. If the MFile already exists in the current list, leave it in the list. If anything changes, send TriggerEvent(TriggerType.update) and return true Get the results from getFiles()

Returns:

true if anything actually changed.

Throws:

IOException - on I/O error

addEventListener

void addEventListener(CollectionManager.TriggerListener l)

Register to get Trigger events

Parameters:

l - listener

removeEventListener

void removeEventListener(CollectionManager.TriggerListener l)