Main.java Source code

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Here is the source code for Main.java

Source

//package com.java2s;
/*
 * Copyright 2012 Google Inc.
 *
 * 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.
 */

import android.util.Log;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Random;

public class Main {
    private static final String TAG = "ClientUtilities";
    private static final int BACKOFF_MILLI_SECONDS = 2000;
    private static final Random random = new Random();

    /** Issue a POST with exponential backoff */
    private static String post(String endpoint, Map<String, String> params, int maxAttempts) throws IOException {
        long backoff = BACKOFF_MILLI_SECONDS + random.nextInt(1000);
        for (int i = 1; i <= maxAttempts; i++) {
            Log.d(TAG, "Attempt #" + i + " to connect");
            try {
                return executePost(endpoint, params);
            } catch (IOException e) {
                Log.e(TAG, "Failed on attempt " + i + ":" + e);
                if (i == maxAttempts) {
                    throw e;
                }
                try {
                    Thread.sleep(backoff);
                } catch (InterruptedException e1) {
                    Thread.currentThread().interrupt();
                    return null;
                }
                backoff *= 2;
            } catch (IllegalArgumentException e) {
                throw new IOException(e.getMessage(), e);
            }
        }
        return null;
    }

    /**
     * Issue a POST request to the server.
     *
     * @param endpoint POST address.
     * @param params request parameters.
     * @return response
     * @throws IOException propagated from POST.
     */
    private static String executePost(String endpoint, Map<String, String> params) throws IOException {
        URL url;
        StringBuffer response = new StringBuffer();
        try {
            url = new URL(endpoint);
        } catch (MalformedURLException e) {
            throw new IllegalArgumentException("invalid url: " + endpoint);
        }
        StringBuilder bodyBuilder = new StringBuilder();
        Iterator<Entry<String, String>> iterator = params.entrySet().iterator();
        // constructs the POST body using the parameters
        while (iterator.hasNext()) {
            Entry<String, String> param = iterator.next();
            bodyBuilder.append(param.getKey()).append('=').append(param.getValue());
            if (iterator.hasNext()) {
                bodyBuilder.append('&');
            }
        }
        String body = bodyBuilder.toString();
        //Log.v(TAG, "Posting '" + body + "' to " + url);
        byte[] bytes = body.getBytes();
        HttpURLConnection conn = null;
        try {
            conn = (HttpURLConnection) url.openConnection();
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setUseCaches(false);
            conn.setFixedLengthStreamingMode(bytes.length);
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");

            // post the request
            OutputStream out = conn.getOutputStream();
            out.write(bytes);
            out.close();

            // handle the response
            int status = conn.getResponseCode();
            if (status != 200) {
                throw new IOException("Post failed with error code " + status);

            } else {
                BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
                String inputLine;
                while ((inputLine = in.readLine()) != null) {
                    response.append(inputLine);
                }
                in.close();
            }
        } finally {
            if (conn != null) {
                conn.disconnect();
            }
        }
        return response.toString();
    }
}