Creating your own OCR Data Capture plugin

You can create your own OCR Data Capture plugin.


  • The new OCR Data Capture class must implement the "OCRTemplateParser" interface.
  • The new OCR Data Capture class must be declared under the package "com.openkm.plugin.ocr.template.parser".
  • The new OCR Data Capture class must be annotated with "@PluginImplementation".
  • The new OCR Data Capture class must extend of "BasePlugin".

OCR Data Capture interface:

package com.openkm.plugin.ocr.template;

import com.openkm.db.bean.OCRTemplateField;
import net.xeoh.plugins.base.Plugin;

 * OCRTemplateParser
public interface OCRTemplateParser extends Plugin {

    Object parse(OCRTemplateField otf, String text) throws OCRTemplateException, OCRParserEmptyValueException;

    String getName();

    boolean isPatternRequired();

The new class must be loaded into the package com.openkm.plugin.ocr.template.parser because application plugins system will try to load from there.

Do not miss the tag @PluginImplementation otherwise the application plugin system will not be able to retrieve the new class.

More information at  Register a new plugin.

Methods description


parse(OCRTemplateField otf, String text)


Returns the value of the data captured into an Object.

Allowed Object classes:

  • String
  • Calendar ( will be converted to ISO8601 String )
  • Other ( will be converted to string with String.valueOf(object).



Sets the name that will be shown in the administrator user interface selector list.



When returns true indicates that the pattern field is required.

Will show an error - missing pattern - on the administrator user interface if pattern is required and the user is not set.


StringParser class:

package com.openkm.plugin.ocr.template.parser;

import com.openkm.db.bean.OCRTemplateField;
import com.openkm.plugin.BasePlugin;
import com.openkm.plugin.ocr.template.OCRParserEmptyValueException;
import com.openkm.plugin.ocr.template.OCRTemplateException;
import com.openkm.plugin.ocr.template.OCRTemplateParser;
import net.xeoh.plugins.base.annotations.PluginImplementation;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

 * StringParser
public class StringParser extends BasePlugin implements OCRTemplateParser {

    public Object parse(OCRTemplateField otf, String text) throws OCRTemplateException, OCRParserEmptyValueException {
        if (text == null || text.equals("")) {
            throw new OCRParserEmptyValueException("Empty value");

        if (otf.getPattern() == null || otf.getPattern().equals("")) {
            return text != null ? text.trim() : null;
        } else {
            Pattern pattern = Pattern.compile("(" + otf.getPattern() + ")", Pattern.UNICODE_CASE);
            Matcher matcher = pattern.matcher(text);

            if (matcher.find() && matcher.groupCount() == 1) {
            } else {
                throw new OCRTemplateException("Bad format, parse exception");

    public String getName() {
        return "String";

    public boolean isPatternRequired() {
        return false;