com.division.jsonrpc.JsonClient.java Source code

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Here is the source code for com.division.jsonrpc.JsonClient.java

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/*
 *Copyright 2014 Evan Cleary.
 *
 *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.division.jsonrpc;

import com.division.jsonrpc.api.JsonRequest;
import com.division.jsonrpc.api.RPCCallback;
import com.division.jsonrpc.api.RPCTransport;
import com.division.jsonrpc.api.SuperclassExclusionStrategy;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.stream.JsonReader;

import java.io.InputStream;
import java.io.OutputStream;
import java.io.StringReader;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * Creates a client capable of performing RPC transactions
 * with the specified server. All requests and responses are
 * handled asynchronously with a callback system.
 */
public class JsonClient {

    private Gson gson;
    private GsonBuilder gsonBuilder;

    private final String rpcServer;

    public JsonClient(String rpcServer) {
        this.rpcServer = rpcServer;
        gsonBuilder = new GsonBuilder().disableHtmlEscaping()
                .excludeFieldsWithModifiers(Modifier.VOLATILE, Modifier.TRANSIENT)
                .setExclusionStrategies(new SuperclassExclusionStrategy());
        gson = gsonBuilder.create();
    }

    public void sendRequest(final JsonRequest request, final Type returnType, final RPCCallback callback) {
        Thread t = new Thread() {
            public void run() {
                RPCTransport response;
                String jRequest = gson.toJson(request);
                HttpURLConnection urlConnection = null;
                try {
                    URL server = new URL(rpcServer);
                    urlConnection = (HttpURLConnection) server.openConnection();
                    urlConnection.setRequestMethod("POST");
                    urlConnection.setRequestProperty("content-type", "application/json");
                    urlConnection.setDoOutput(true);
                    OutputStream oStream = urlConnection.getOutputStream();
                    System.out.println(jRequest);
                    oStream.write(jRequest.getBytes());
                    oStream.flush();
                    oStream.close();

                    InputStream rStream = urlConnection.getInputStream();
                    String responseString = "";
                    int bytes;
                    byte[] bytesRec = new byte[51200];
                    while ((bytes = rStream.read(bytesRec, 0, bytesRec.length)) != -1) {
                        responseString += new String(bytesRec, 0, bytes);
                    }
                    rStream.close();
                    responseString = responseString.trim();
                    if (callback != null) {
                        JsonReader jReader = new JsonReader(new StringReader(responseString));
                        jReader.setLenient(true);
                        response = gson.fromJson(jReader, returnType);
                        callback.onResponseReceived(response);
                    }
                    urlConnection.disconnect();
                } catch (Exception e) {
                    e.printStackTrace();
                    System.out.println("JSONRPC: EXCEPTION");
                } finally {
                    if (urlConnection != null) {
                        urlConnection.disconnect();
                    }
                }
            }
        };
        t.setDaemon(true);
        t.start();
    }
}