net.ontopia.topicmaps.nav2.servlets.AutoSuggestServlet.java Source code

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Here is the source code for net.ontopia.topicmaps.nav2.servlets.AutoSuggestServlet.java

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/*
 * #!
 * Ontopia Navigator
 * #-
 * Copyright (C) 2001 - 2013 The Ontopia Project
 * #-
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * !#
 */

package net.ontopia.topicmaps.nav2.servlets;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Collections;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import net.ontopia.topicmaps.core.TopicIF;
import net.ontopia.topicmaps.core.TopicMapStoreIF;
import net.ontopia.topicmaps.entry.TopicMaps;
import net.ontopia.topicmaps.query.core.QueryProcessorIF;
import net.ontopia.topicmaps.query.core.QueryResultIF;
import net.ontopia.topicmaps.query.utils.QueryUtils;
import net.ontopia.topicmaps.utils.TopicStringifiers;
import org.apache.commons.lang3.StringUtils;

/**
 * INTERNAL: Experimental auto suggest servlet.
 */
public class AutoSuggestServlet extends HttpServlet {

    private int limit = 25;
    private String query = "select $T, $DESC from value-like($TN, %TERM%), topic-name($T, $TN), { i\"http://purl.org/dc/elements/1.1/description\"($T, $DESC) } order by $T, $DESC desc?";

    @Override
    public void init() throws ServletException {
        // no-op
    }

    @Override
    public void destroy() {
        // no-op
    }

    private String escape(String s) {
        return StringUtils.replace(StringUtils.replace(s, "\"", "\\\""), "\n", " ");
    }

    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/plain; charset=utf-8");

        String tmid = request.getParameter("tm");
        if (tmid == null)
            throw new ServletException("Parameter tm is not given.");
        String term = request.getParameter("term");
        if (term == null)
            throw new ServletException("Parameter term is not given.");

        TopicMapStoreIF store = TopicMaps.createStore(tmid, true);

        if (store instanceof net.ontopia.topicmaps.impl.basic.InMemoryTopicMapStore)
            term = term + '*';

        try {
            QueryProcessorIF qp = QueryUtils.getQueryProcessor(store.getTopicMap());
            QueryResultIF qr = qp.execute(query, Collections.singletonMap("TERM", term));
            System.out.println("query: " + query);
            PrintWriter w = response.getWriter();
            w.write("{ results: [\n");
            int count = 0;
            while (qr.next()) {
                if (count > limit)
                    break;
                if (count > 0)
                    w.write(",\n");
                TopicIF topic = (TopicIF) qr.getValue(0);
                String desc = (String) qr.getValue(1);
                w.write("    { id: \"");
                w.write(topic.getObjectId());
                w.write("\", value: \"");
                w.write(escape(TopicStringifiers.toString(topic)));
                w.write("\", info: \"");
                w.write((desc == null ? "" : escape(desc)));
                w.write("\" }");
                count++;
            }
            w.write("\n] }\n");

        } catch (Exception e) {
            throw new ServletException(e);
        } finally {
            store.close();
        }
    }

}