mml.handler.MMLHandler.java Source code

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Here is the source code for mml.handler.MMLHandler.java

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/*
 * This file is part of MML.
 *
 *  MML is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  MML is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with MML.  If not, see <http://www.gnu.org/licenses/>.
 *  (c) copyright Desmond Schmidt 2014
 */
package mml.handler;

import calliope.core.constants.JSONKeys;
import calliope.core.database.Connection;
import calliope.core.exception.DbException;
import mml.exception.MMLException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.nio.charset.Charset;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.JSONValue;

/**
 * Abstract super-class for all handlers: PUT, POST, DELETE, GET
 * @author ddos
 */
abstract public class MMLHandler {
    protected String encoding;
    protected String docid;
    protected String version1;

    private boolean isAnnotation(JSONObject jObj) {
        if (jObj.containsKey(JSONKeys.OFFSET) && jObj.containsKey(JSONKeys.LEN) && jObj.containsKey(JSONKeys.USER)
                && jObj.containsKey(JSONKeys.CONTENT))
            return true;
        else
            return false;
    }

    /**
     * Fetch one annotation from some database
     * @param conn the connection to the database
     * @param coll the database collection
     * @param docId the specific docid to match against
     * @return a JSONObject or null
     * @throws DbException 
     */
    protected JSONObject fetchAnnotation(Connection conn, String coll, String docId) throws DbException {
        String jDoc = conn.getFromDb(coll, docId);
        JSONObject jObj = (JSONObject) JSONValue.parse(jDoc);
        if (isAnnotation(jObj)) {
            if (jObj.containsKey(JSONKeys.VERSIONS)) {
                JSONArray versions = (JSONArray) jObj.get(JSONKeys.VERSIONS);
                if (versions.contains(version1))
                    return jObj;
            }
        }
        return null;
    }

    public MMLHandler() {
        this.encoding = Charset.defaultCharset().name();
    }

    public abstract void handle(HttpServletRequest request, HttpServletResponse response, String urn)
            throws MMLException;
}