org.ow2.weblab.service.language
Class LanguageExtraction

java.lang.Object
  org.ow2.weblab.service.language.LanguageExtraction

All Implemented Interfaces:

org.ow2.weblab.core.services.Analyser

public class LanguageExtraction
extends java.lang.Object
implements org.ow2.weblab.core.services.Analyser

This class is a WebLab Web service for identifying the language of a Text.
It's a wrapper of the NGramJ project: "http://ngramj.sourceforge.net/". It uses the CNGram system that can computes character string instead of raw text files.
This algorithm return for each input text a score associated to every language profile previously learned (.ngp files). The score is a double between 0 and 1. 1 meaning that this text is written in this language for sure. 0 on the opposite means that this text is not written in this language. The sum of score equals 1.
Our wrapper annotate every Text section of a ComposedUnit in input (or the Text if the input is a Text). It fails if the input is something else. On each Text it uses CGram to determine which language profile are the best candidate to be annotated (using DC:language property). It can be configured using a property file named ngram.properties. In this file you can handle 7 properties.

• minSingleValue: It's a double value between 0 and 1. If the best language score is greater than this value, it will be the only one annotated on a given Text
• minMultipleValue: It's a double value between 0 and 1. Every language score that are greater than this value, will be annotated on a given Text.
• maxNbValues: It's a positive integer value. The list of annotated language on a given Text could not be greater that this value.
• profilesFolderPath: It's a String that represents a folder path; This folder contains .ngp files that will be loaded instead of default CNGram 28 languages.
• addTopLevelAnnot: It's a boolean value. It defines whether or not to annotate the whole document with the language extracted from the concatenation of every Text content.
• addMediaUnitLevelAnnot: It's a boolean value. It defines whether or not to annotate the each Text section with the language guessed.
• isProducedByObject: It's a String value that should be a valid URI. It defines the URI to be used as object of every isProducedBy statements on annotations created by the service.

Those 7 properties are optional. Default values are:

• minSingleValue: '0.75'
• minMultipleValue: '0.15'
• maxNbValues: '1'
• profilesFolderPath: in this case, we use the default constructor for CNGram profile that will use default profile given in their jar file. These 28 profiles are named using ISO 639-1 two letters language code; it means that the DC:language annotation resulting will be in this format. If you want to use another format, you have use a custom profiles folder (containing .ngp files).
• addTopLevelAnnot: false
• addTopLevelAnnot: true
• isProducedByObject: null in this case, no isProducedBy annotation will be created.

Author:

EADS IPCC Team

Date:

2009-11-05

Constructor Summary

LanguageExtraction()

Method Summary

void	init() Read the property file to get fields values.
org.ow2.weblab.core.services.analyser.ProcessReturn	process(org.ow2.weblab.core.services.analyser.ProcessArgs processArgs)

Methods inherited from class java.lang.Object

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

Constructor Detail

LanguageExtraction

public LanguageExtraction()

Method Detail

init

@PostConstruct
public void init()
          throws LanguageExtractionException

Read the property file to get fields values.

Throws:

LanguageExtractionException

process

public org.ow2.weblab.core.services.analyser.ProcessReturn process(org.ow2.weblab.core.services.analyser.ProcessArgs processArgs)
                                                            throws org.ow2.weblab.core.services.AccessDeniedException,
                                                                   org.ow2.weblab.core.services.ContentNotAvailableException,
                                                                   org.ow2.weblab.core.services.InsufficientResourcesException,
                                                                   org.ow2.weblab.core.services.InvalidParameterException,
                                                                   org.ow2.weblab.core.services.ServiceNotConfiguredException,
                                                                   org.ow2.weblab.core.services.UnexpectedException,
                                                                   org.ow2.weblab.core.services.UnsupportedRequestException

Specified by:

process in interface org.ow2.weblab.core.services.Analyser

Throws:

org.ow2.weblab.core.services.AccessDeniedException

org.ow2.weblab.core.services.ContentNotAvailableException

org.ow2.weblab.core.services.InsufficientResourcesException

org.ow2.weblab.core.services.InvalidParameterException

org.ow2.weblab.core.services.ServiceNotConfiguredException

org.ow2.weblab.core.services.UnexpectedException

org.ow2.weblab.core.services.UnsupportedRequestException