cbr.agent
Class CCVGathererAgent

java.lang.Object
  de.fhg.igd.semoa.agent.RoundtripAgent
      cbr.agent.CCVGathererAgent

All Implemented Interfaces:

Runnable, Serializable

public class CCVGathererAgent

extends RoundtripAgent

This gatherer agent hops to a number of agent servers and collects index information of pictures provided by the visited servers. Indexing is done according to the 'Color Coherence Vector' scheme published by Pass et al.

The agent needs to be configured in a certain way. In particular its itinerary must be specified by means of the agent's properties.

pics = <string>

The path to the PicsSource service.

idx = <string>

The path to the PicsIndex service.

hop.<num> = <URL>

The URL string of the <num>'th hop, starting with 0.

hop.final = <URL>

The URL string of the final hop where the index is going to be updated.

thumbs = <boolean>

"true" iff thumbnails shall be fetched.

Version:

"$Id: CCVGathererAgent.java 1913 2007-08-08 02:41:53Z jpeters $"

Author:

Patric Kabus, Volker Roth

See Also:

Serialized Form

Field Summary

static String	NAME_IDX The name of the index file.
static String	NAME_THUMBS The name of the directory in which thumbnails are kept.
static String	NAME_TMP The name of the temporary index file.
protected long	time_ The time this agent started (the first time it is run).

Fields inherited from class de.fhg.igd.semoa.agent.RoundtripAgent

debug_, env_, MAX_RETRIES, mob_, start_, vars_

Constructor Summary

CCVGathererAgent()

Method Summary

protected void	finish() This method shall be executed when the gatherer is at its destination host on which it is expected to update the index with the collected PictureEntries.
void	onRunning() This method is called upon running the agent.
protected void	perform() Gathers the feature vectors of local pictures.

Methods inherited from class de.fhg.igd.semoa.agent.RoundtripAgent

getHopNumber, run

Methods inherited from class java.lang.Object

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

Field Detail

NAME_IDX

public static final String NAME_IDX

The name of the index file.

See Also:

Constant Field Values

NAME_TMP

public static final String NAME_TMP

The name of the temporary index file.

See Also:

Constant Field Values

NAME_THUMBS

public static final String NAME_THUMBS

The name of the directory in which thumbnails are kept.

See Also:

Constant Field Values

time_

protected long time_

The time this agent started (the first time it is run).

Constructor Detail

CCVGathererAgent

public CCVGathererAgent()

Method Detail

onRunning

public void onRunning()

This method is called upon running the agent. It initialises some fields required by the agent and creates empty index files for the current hop if none exists yet.

On each hop, a dummy index file is created in the mutable part of the agent. The files' names are of the form <n>/idx, where <n> stands for the number of the hop. Hop numbers starts with zero. If the structure is mapped to a file system then the above form implies that a directory is created for each hop. This allows to set a security policy which controls access to the individual indexes.

Overrides:

onRunning in class RoundtripAgent

perform

protected void perform()
                throws Exception

Gathers the feature vectors of local pictures. This requires that a PicsSource service is installed locally. The path to this service is configured by means of the agent's properties. The relevant property is:

pics = <string>

The path where the PicsSource is expected to be published.

Overrides:

perform in class RoundtripAgent

Throws:

Exception - if something's wrong.

finish

protected void finish()
               throws Exception

This method shall be executed when the gatherer is at its destination host on which it is expected to update the index with the collected PictureEntries.

The name and level of the PicsIndex to use must be configured in the agent's properties. The property is:

idx = <string>

The path where the PicsIndex is expected to be published.

Overrides:

finish in class RoundtripAgent

Throws:

if - somethong's wrong.

Exception