org.imixs.archive.documents

Class TikaService

java.lang.Object

org.imixs.archive.documents.TikaService

public class TikaService
extends Object

The OCRService extracts the textual information from document attachments of a workitem and stores the data into the $file attribute 'text'.

For the text extraction the services sends the content of a document to an instance of a Apache Tika server via the Rest API. The environment variable OCR_STRATEGY defines how PDF files will be scanned. Possible values are:

• AUTO - The best OCR strategy is chosen by the Tika Server itself. This is the default setting.
• NO_OCR - OCR processing is disabled and text is extracted only from PDF files including a raw text. If a pdf file does not contain raw text data no text will be extracted!
• OCR_ONLY - PDF files will always be OCR scanned even if the pdf file contains text data.
• OCR_AND_TEXT_EXTRACTION - OCR processing and raw text extraction is performed. Note: This may result is a duplication of text and the mode is not recommended.

The service expects a valid Rest API end-point to an instance of a Tika Server defined by the Environment Parameter 'TIKA_SERVICE_ENDPONT'.

The environment parameter 'TIKA_SERVICE_MODE' must be set to 'auto' to enable the service.

See also the project: https://github.com/imixs/imixs-docker/tree/master/tika

Version:

1.1

Author:

rsoika

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_ENCODING
static String	ENV_OCR_SERVICE_ENDPOINT
static String	ENV_OCR_SERVICE_MAXFILESIZE
static String	ENV_OCR_SERVICE_MODE
static String	ENV_OCR_STRATEGY
static String	FILE_ATTRIBUTE_TEXT
static String	OCR_STRATEGY_AUTO
static String	OCR_STRATEGY_NO_OCR
static String	OCR_STRATEGY_OCR_AND_TEXT_EXTRACTION
static String	OCR_STRATEGY_OCR_ONLY
static String	PLUGIN_ERROR

Constructor Summary

Constructors

Constructor and Description
TikaService()

Method Summary

Modifier and Type	Method and Description
String	doORCProcessing(org.imixs.workflow.FileData fileData, List<String> options, int maxPdfPages) This method sends the content of a document to the Tika Rest API for OCR processing.
void	extractText(org.imixs.workflow.ItemCollection workitem, org.imixs.workflow.ItemCollection snapshot) Extracts the textual information from document attachments.
void	extractText(org.imixs.workflow.ItemCollection workitem, org.imixs.workflow.ItemCollection snapshot, String _ocrStategy, List<String> options, String filePatternRegex, int maxPdfPages) Extracts the textual information from document attachments.

Methods inherited from class java.lang.Object

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

Field Detail

FILE_ATTRIBUTE_TEXT

public static final String FILE_ATTRIBUTE_TEXT

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Constant Field Values

DEFAULT_ENCODING

public static final String DEFAULT_ENCODING

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Constant Field Values

PLUGIN_ERROR

public static final String PLUGIN_ERROR

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Constant Field Values

ENV_OCR_SERVICE_ENDPOINT

public static final String ENV_OCR_SERVICE_ENDPOINT

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Constant Field Values

ENV_OCR_SERVICE_MODE

public static final String ENV_OCR_SERVICE_MODE

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Constant Field Values

ENV_OCR_SERVICE_MAXFILESIZE

public static final String ENV_OCR_SERVICE_MAXFILESIZE

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Constant Field Values

ENV_OCR_STRATEGY

public static final String ENV_OCR_STRATEGY

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Constant Field Values

OCR_STRATEGY_NO_OCR

public static final String OCR_STRATEGY_NO_OCR

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Constant Field Values

OCR_STRATEGY_OCR_AND_TEXT_EXTRACTION

public static final String OCR_STRATEGY_OCR_AND_TEXT_EXTRACTION

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Constant Field Values

OCR_STRATEGY_OCR_ONLY

public static final String OCR_STRATEGY_OCR_ONLY

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Constant Field Values

OCR_STRATEGY_AUTO

public static final String OCR_STRATEGY_AUTO

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Constant Field Values

Constructor Detail

TikaService

public TikaService()

Method Detail

extractText

public void extractText(org.imixs.workflow.ItemCollection workitem,
                        org.imixs.workflow.ItemCollection snapshot)
                 throws org.imixs.workflow.exceptions.PluginException

Extracts the textual information from document attachments.

The method extracts the textual content for each new document of a given workitem. For PDF files with textual content the method calls the method 'extractTextFromPDF' using the PDFBox api. In other cases, the method sends the content via a Rest API to the tika server for OCR processing.

The result is stored into the fileData attribute 'text'

Parameters:

workitem -

Throws:

org.imixs.workflow.exceptions.PluginException

extractText

public void extractText(org.imixs.workflow.ItemCollection workitem,
                        org.imixs.workflow.ItemCollection snapshot,
                        String _ocrStategy,
                        List<String> options,
                        String filePatternRegex,
                        int maxPdfPages)
                 throws org.imixs.workflow.exceptions.PluginException

Extracts the textual information from document attachments.

The method extracts the textual content for each new file attachment of a given workitem. The text information is stored in the $file attribute 'text'.

For PDF files with textual content the method calls the method 'extractTextFromPDF' using the PDFBox api. In other cases, the method sends the content via a Rest API to the tika server for OCR processing.

The method also extracts files already stored in a snapshot workitem. In this case the method tests if the $file attribute 'text' already exists.

An optional param 'filePattern' can be provided to extract text only from Attachments mating the given file pattern (regex).

The optioanl param 'maxPages' can be provided to reduce the size of PDF documents to a maximum of pages. This avoids blocking the tika service by processing to large documetns. For example only the first 5 pages can be scanned.

Parameters:

workitem - - workitem with file attachments

pdf_mode - - TEXT_ONLY, OCR_ONLY, TEXT_AND_OCR

options - - optional tika header params

filePatternRegex - - optional regular expression to match files

Throws:

org.imixs.workflow.exceptions.PluginException

doORCProcessing

public String doORCProcessing(org.imixs.workflow.FileData fileData,
                              List<String> options,
                              int maxPdfPages)
                       throws IOException

This method sends the content of a document to the Tika Rest API for OCR processing.

In case the contentType is PDF then the following tika specific header is added:

X-Tika-PDFOcrStrategy: ocr_only

Parameters:

fileData - - file content and metadata

Returns:

text content

Throws:

IOException