Creating your own Text extractor

You can create your own Text Extractor

Conditions

• The new Text Extractor class must be declared under the package "com.openkm.extractor".
• The new Text Extractor class must be annotated with "@PluginImplementation".
• The new Text Extractor class must extend of "AbstractTextExtractor".

Text Extractor interface:

package com.openkm.extractor;

import net.xeoh.plugins.base.Plugin;

import java.io.IOException;
import java.io.InputStream;

public interface TextExtractor extends Plugin {
    
    String[] getContentTypes();

    String extractText(InputStream stream, String type, String encoding) throws IOException;
}

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

Methods description

Example of the Text extractor implementation

package com.openkm.extractor;

import net.xeoh.plugins.base.annotations.PluginImplementation;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;

/**
 * Text extractor for plain text.
 */
@PluginImplementation
public class PlainTextExtractor extends AbstractTextExtractor {

    private static final Logger log = LoggerFactory.getLogger(PlainTextExtractor.class);

    /**
     * Creates a new <code>PlainTextExtractor</code> instance.
     */
    public PlainTextExtractor() {
        super(new String[]{"text/plain"});
    }

    // -------------------------------------------------------< TextExtractor >
    /**
     * Wraps the given input stream to an {@link InputStreamReader} using the
     * given encoding, or the platform default encoding if the encoding is not
     * given or is unsupported. Closes the stream and returns an empty reader if
     * the given encoding is not supported.
     *
     * @param stream binary stream
     * @param type ignored
     * @param encoding character encoding, optional
     * @return reader for the plain text content
     * @throws IOException if the binary stream can not be closed in case of an
     * encoding issue
     */
    @Override
    public String extractText(InputStream stream, String type, String encoding) throws IOException {
        log.debug("extractText({}, {}, {})", stream, type, encoding);

        try {
            if (encoding != null) {
                return IOUtils.toString(stream, encoding);
            }
        } catch (UnsupportedEncodingException e) {
            log.warn("Unsupported encoding '{}', using default ({}) instead.", encoding, System.getProperty("file.encoding"));
        }

        return IOUtils.toString(stream, StandardCharsets.UTF_8);
    }
}