org.hypertopic.DistributedRESTDatabase.java Source code

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Here is the source code for org.hypertopic.DistributedRESTDatabase.java

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/*
HYPERTOPIC - Infrastructure for community-driven knowledge organization systems
    
OFFICIAL WEB SITE
http://www.hypertopic.org/
    
Copyright (C) 2012 Aurelien Benel.
    
LEGAL ISSUES
This library is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free 
Software Foundation, either version 3 of the license, or (at your option) any
later version.
This library 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 Lesser General Public License for more details:
http://www.gnu.org/licenses/lgpl.html
*/

package org.hypertopic;

import org.json.JSONObject;
import java.util.*;
import java.io.FileNotFoundException;

/**
 * Federation of REST databases:
 * reads are scattered among databases, 
 * writes are forwarded to the primary database.
 */
public class DistributedRESTDatabase extends Observable {//>>>>>>>>>>>>>>>>>>>>>

    private List<RESTDatabase> databases = new ArrayList();

    public DistributedRESTDatabase(String... baseUrls) {
        for (String url : baseUrls) {
            this.databases.add(new RESTDatabase(url));
        }
    }

    protected RESTDatabase getPrimaryServer() {
        return (RESTDatabase) this.databases.get(0);
    }

    public JSONObject post(JSONObject object) throws Exception {
        return this.getPrimaryServer().post(object);
    }

    public synchronized JSONObject getAll(String query) throws Exception {
        Iterator<RESTDatabase> i = this.databases.iterator();
        JSONObject result = new JSONObject();
        while (i.hasNext()) {
            RESTDatabase d = i.next();
            try {
                result.putAll(d.getAll(query));
            } catch (FileNotFoundException e) {
                System.err.println(e);
            }
        }
        return result;
    }

    public JSONObject get(String id) throws Exception {
        return this.getPrimaryServer().get(id);
    }

    public void put(JSONObject object) throws Exception {
        this.getPrimaryServer().put(object);
    }

    public void delete(JSONObject object) throws Exception {
        this.getPrimaryServer().delete(object);
    }

    public void startListening() {
        for (RESTDatabase db : this.databases) {
            db.startListening();
        }
    }

    @Override
    public void addObserver(Observer o) {
        for (RESTDatabase db : this.databases) {
            db.addObserver(o);
        }
    }

}//<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< DistributedRESTDatabase