QueueTreeClient.java

/*
 * Copyright 2009 VoidSearch.com
 *
 * 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 com.voidsearch.voidbase.apps.queuetree.client;

import com.voidsearch.voidbase.client.VoidBaseHttpClient;
import com.voidsearch.voidbase.apps.queuetree.protocol.QueueTreeProtocol;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathFactory;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathConstants;
import java.util.List;
import java.util.LinkedList;
import java.io.DataInputStream;
import java.io.ByteArrayInputStream;

import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Node;

public class QueueTreeClient extends VoidBaseHttpClient {

    public QueueTreeClient() {
        this.hostname = "localhost:8080";
        this.module = "/queuetree";
    }

    public QueueTreeClient(String hostname) {
        this.hostname = hostname;
        this.module = "/queuetree";
    }

    public void create(String queue, Integer size) throws Exception {

        QueueTreeQuery query = new QueueTreeQuery(hostname);
        query.set(QueueTreeProtocol.METHOD, "ADD");
        query.set(QueueTreeProtocol.QUEUE, queue);
        query.set(QueueTreeProtocol.SIZE, size.toString());

        get(query);
    }

    public void delete(String queue) throws Exception {

        QueueTreeQuery query = new QueueTreeQuery(hostname);
        query.set(QueueTreeProtocol.METHOD, "DELETE");
        query.set(QueueTreeProtocol.QUEUE, queue);

        get(query);
    }


    public void put(String queue, String content) throws Exception {

        QueueTreeQuery query = new QueueTreeQuery(hostname);
        query.set(QueueTreeProtocol.METHOD, "PUT");
        query.set(QueueTreeProtocol.QUEUE, queue);

        post(query,content);

    }

    public String get(String queue, Integer size) throws Exception {

        QueueTreeQuery query = new QueueTreeQuery(hostname);
        query.set(QueueTreeProtocol.METHOD, "GET");
        query.set(QueueTreeProtocol.QUEUE, queue);
        query.set(QueueTreeProtocol.SIZE, size.toString());

        return new String(get(query));

    }

    public String list() throws Exception {

        QueueTreeQuery query = new QueueTreeQuery(hostname);
        query.set(QueueTreeProtocol.METHOD, "LIST");
        return new String(get(query));

    }

    // parse response
    public LinkedList<String> getResultList(String response) throws Exception {

        LinkedList<String> resultList = new LinkedList<String>();

        DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = domFactory.newDocumentBuilder();
        Document doc = builder.parse(new DataInputStream(new ByteArrayInputStream(response.getBytes())));
        
        XPath xpath = XPathFactory.newInstance().newXPath();

        XPathExpression expr = xpath.compile("//queue/response/queueElements/entry/val");

        Object result = expr.evaluate(doc, XPathConstants.NODESET);
        NodeList nodes = (NodeList) result;
        
        for (int i=0; i<nodes.getLength(); i++) {
            resultList.add(nodes.item(i).getTextContent());
        }

        return resultList;
    }

}