this.target = value;
    }

    public String getThumbnailId() {
        checkSpecifiedProperty("thumbnailId");
        return convertEmptyToNull(thumbnailId);
    }

    public void setThumbnailId(String value) {
        registerModifiedProperty("thumbnailId");
        this.thumbnailId = value;
    }

{
    "properties": {
      "thumbnail_id": {
        "type": "keyword"
      },
      "path": {
        "type": "keyword"
      },
      "generator": {
        "type": "keyword"
      },
      "target": {
        "type": "keyword"
      },
      "createdTime": {
        "type": "long"
      },
      "createdBy": {
        "type": "keyword"
      }
    }

            "type" : "keyword"
          },
          "path" : {
            "type" : "keyword"
          },
          "target" : {
            "type" : "keyword"
          },
          "thumbnail_id" : {
            "type" : "keyword"
          }
        }
      }
    },
    "settings" : {
      "index" : {
        "creation_date" : "1509021057304",
        "number_of_shards" : "5",

            doColumn("path");
        }

        public void columnTarget() {
            doColumn("target");
        }

        public void columnThumbnailId() {
            doColumn("thumbnail_id");
        }
    }

    public void destroy() {
        destoryTimer.cancel();
        destoryTimer = null;
    }

    @Override
    public boolean generate(final String thumbnailId, final File outputFile) {
        if (logger.isDebugEnabled()) {
            logger.debug("Generate Thumbnail: {}", thumbnailId);
        }

        if (outputFile.exists()) {
            if (logger.isDebugEnabled()) {

            return false;
        }

        return process(thumbnailId, responseData -> {
            if (!isImageMimeType(responseData)) {
                if (logger.isDebugEnabled()) {
                    logger.debug("Thumbnail is not image: {} : {}", thumbnailId, responseData.getUrl());
                }
                updateThumbnailField(thumbnailId, StringUtil.EMPTY);
                return false;
            }

 */
package org.codelibs.fess.thumbnail.impl;

import java.io.File;

public class EmptyGenerator extends BaseThumbnailGenerator {

    @Override
    public boolean generate(final String thumbnailId, final File outputFile) {
        return false;
    }

    @Override
    public void destroy() {
        // nothing
    }

import java.io.File;
import java.util.Map;

import org.codelibs.core.misc.Tuple3;

public interface ThumbnailGenerator {

    String getName();

    boolean generate(String thumbnailId, File outputFile);

    boolean isTarget(Map<String, Object> docMap);

    boolean isAvailable();

    void destroy();

    Tuple3<String, String, String> createTask(String path, Map<String, Object> docMap);

            systemProperties.reload(options.propertiesPath);
        } else {
            try {
                final File propFile = ComponentUtil.getSystemHelper().createTempFile("thumbnail_", ".properties");
                if (propFile.delete() && logger.isDebugEnabled()) {
                    logger.debug("Deleted a temp file: {}", propFile.getAbsolutePath());
                }