ser423.CalculatorSkeleton.java Source code

Introduction

Here is the source code for ser423.CalculatorSkeleton.java

Source

package ser423;

import java.net.*;
import java.io.*;
import java.util.*;
import org.json.JSONObject;
import org.json.JSONArray;
import java.text.NumberFormat;

/**
 * Copyright (c) 2014 Tim Lindquist,
 *
 * 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.
 * <p/>
 * Purpose: This class is part of an example developed for the mobile
 * computing class at ASU Poly. The application provides a calculator service.
 * The client and service are both written in Java and they 
 * communicate using JSON-RPC.
 * <p/>
 * The Caclulator interface provides the method definitions used by the client
 * and implemented by the calculator service.
 *
 * @author Tim Lindquist
 * @version 2/1/2015
 **/
public class CalculatorSkeleton extends Object {

    CalculatorImpl ci; //the calculator implementation

    public CalculatorSkeleton() {
        super();
        ci = new CalculatorImpl();
    }

    public String callMethod(String request) {
        JSONObject result = new JSONObject();
        NumberFormat nf = NumberFormat.getInstance();
        nf.setMaximumFractionDigits(2);
        try {
            JSONObject theCall = new JSONObject(request);
            String method = theCall.getString("method");
            int id = theCall.getInt("id");
            JSONArray params = null;
            if (!theCall.isNull("params")) {
                params = theCall.getJSONArray("params");
            }
            result.put("id", id);
            result.put("jsonrpc", "2.0");
            double left = 0;
            double right = 0;
            if (params.length() > 0) {
                left = params.getDouble(0);
            }
            if (params.length() > 1) {
                right = params.getDouble(1);
            }
            if (method.equals("add")) {
                System.out.println("request: " + nf.format(left) + " + " + nf.format(right));
                double res = ci.add(left, right);
                result.put("result", res);
            } else if (method.equals("subtract")) {
                System.out.println("request: " + nf.format(left) + " - " + nf.format(right));
                double res = ci.subtract(left, right);
                result.put("result", res);
            } else if (method.equals("multiply")) {
                System.out.println("request: " + nf.format(left) + " * " + nf.format(right));
                double res = ci.multiply(left, right);
                result.put("result", res);
            } else if (method.equals("divide")) {
                System.out.println("request: " + nf.format(left) + " / " + nf.format(right));
                double res = ci.divide(left, right);
                result.put("result", res);
            } else if (method.equals("whoAreYou")) {
                System.out.println("request: whoAreYou");
                result.put("result", ci.whoAreYou());
            }
        } catch (Exception ex) {
            System.out.println("exception in callMethod: " + ex.getMessage());
        }
        return "HTTP/1.0 200 Data follows\nServer:localhost:8080\nContent-Type:text/plain\nContent-Length:"
                + (result.toString()).length() + "\n\n" + result.toString();
    }
}