net.sourceforge.jwbf.actions.mw.queries.GetTemplateUserTitles.java Source code

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Here is the source code for net.sourceforge.jwbf.actions.mw.queries.GetTemplateUserTitles.java

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/*
 * Copyright 2007 Tobias Knerr.
 * 
 * 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.
 * 
 * Contributors:
 * Tobias Knerr
 * 
 */
package net.sourceforge.jwbf.actions.mw.queries;

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Collection;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import net.sourceforge.jwbf.actions.mw.MultiAction;
import net.sourceforge.jwbf.actions.mw.util.MWAction;
import net.sourceforge.jwbf.actions.mw.util.ProcessException;
import net.sourceforge.jwbf.bots.MediaWikiBot;

import org.apache.commons.httpclient.methods.GetMethod;

/**
 * action class using the MediaWiki-api's "list=embeddedin"
 * that is used to find all articles which use a template.
 *
 * @author Tobias Knerr
 * @since MediaWiki 1.9.0
 */
public class GetTemplateUserTitles extends MWAction implements MultiAction<String> {

    /** constant value for the eilimit-parameter. **/
    private static final int LIMIT = 50;

    /**
     * Collection that will contain the result
     * (titles of articles using the template) 
     * after performing the action has finished.
     */
    private Collection<String> titleCollection = new ArrayList<String>();

    /**
     * information necessary to get the next api page.
     */
    private String nextPageInfo = null;

    /**
     * The public constructor. It will have an MediaWiki-request generated,
     * which is then added to msgs. When it is answered,
     * the method processAllReturningText will be called
     * (from outside this class).
     * For the parameters, see {@link GetTemplateUserTitles#generateRequest(String, String, String)}
     */
    public GetTemplateUserTitles(String templateName, String namespace) {
        generateRequest(templateName, namespace, null);
    }

    /**
     * The private constructor, which is used to create follow-up actions.
     */
    private GetTemplateUserTitles(String nextPageInfo) {
        generateRequest(null, null, nextPageInfo);
    }

    /**
     * generates the next MediaWiki-request (GetMethod) and adds it to msgs.
     *
     * @param templateName   the name of the template,
     *                      may only be null if eicontinue is not null
     * @param namespace     the namespace(s) that will be searched for links,
     *                      as a string of numbers separated by '|';
     *                      if null, this parameter is omitted
     * @param eicontinue    the value for the eicontinue parameter,
     *                      null for the generation of the initial request
     */
    protected void generateRequest(String templateName, String namespace, String eicontinue) {

        String uS = "";

        try {

            if (eicontinue == null) {

                uS = "/api.php?action=query&list=embeddedin" + "&eititle="
                        + URLEncoder.encode(templateName, MediaWikiBot.CHARSET)
                        + ((namespace != null && !namespace.isEmpty()) ? ("&einamespace=" + namespace) : "")
                        + "&eilimit=" + LIMIT + "&format=xml";

            } else {

                uS = "/api.php?action=query&list=embeddedin" + "&eicontinue="
                        + URLEncoder.encode(eicontinue, MediaWikiBot.CHARSET) + "&eilimit=" + LIMIT + "&format=xml";

            }

            msgs.add(new GetMethod(uS));

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

    }

    /**
     * deals with the MediaWiki api's response by parsing the provided text.
     *
     * @param s   the answer to the most recently generated MediaWiki-request
     *
     * @return empty string
     */
    public String processAllReturningText(final String s) throws ProcessException {
        String t = s;
        parseArticleTitles(t);
        parseHasMore(t);
        return "";
    }

    /**
     * gets the information about a follow-up page from a provided api response.
     * If there is one, a new request is added to msgs by calling generateRequest.
     *   
     * @param s   text for parsing
     */
    protected void parseHasMore(final String s) {

        // get the eicontinue-value

        Pattern p = Pattern.compile(
                "<query-continue>.*?" + "<embeddedin *eicontinue=\"([^\"]*)\" */>" + ".*?</query-continue>",
                Pattern.DOTALL | Pattern.MULTILINE);

        Matcher m = p.matcher(s);

        if (m.find()) {
            nextPageInfo = m.group(1);
        }

    }

    /**
     * picks the article name from a MediaWiki api response.
     *   
     * @param s   text for parsing
     */
    public void parseArticleTitles(String s) {

        // get the backlink titles and add them all to the titleCollection

        Pattern p = Pattern.compile("<ei pageid=\".*?\" ns=\".*?\" title=\"(.*?)\" />");

        Matcher m = p.matcher(s);

        while (m.find()) {
            titleCollection.add(m.group(1));
        }

    }

    /**
     * @return   the collected article names
     */
    public Collection<String> getResults() {
        return titleCollection;
    }

    /**
     * @return   necessary information for the next action
     *           or null if no next api page exists
     */
    public GetTemplateUserTitles getNextAction() {
        if (nextPageInfo == null) {
            return null;
        } else {
            return new GetTemplateUserTitles(nextPageInfo);
        }
    }

}