org.openqa.selenium.net.UrlChecker.java Source code

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Here is the source code for org.openqa.selenium.net.UrlChecker.java

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// Licensed to the Software Freedom Conservancy (SFC) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The SFC licenses this file
// to you 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 org.openqa.selenium.net;

import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.NANOSECONDS;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Throwables;
import com.google.common.util.concurrent.SimpleTimeLimiter;
import com.google.common.util.concurrent.TimeLimiter;
import com.google.common.util.concurrent.UncheckedTimeoutException;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Arrays;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.logging.Logger;

/**
 * Polls a URL until a HTTP 200 response is received.
 */
public class UrlChecker {

    private static final Logger log = Logger.getLogger(UrlChecker.class.getName());

    private static final int CONNECT_TIMEOUT_MS = 500;
    private static final int READ_TIMEOUT_MS = 1000;
    private static final long POLL_INTERVAL_MS = 500;

    private static final AtomicInteger THREAD_COUNTER = new AtomicInteger(1);
    private static final ExecutorService THREAD_POOL = Executors.newCachedThreadPool(new ThreadFactory() {
        public Thread newThread(Runnable r) {
            Thread t = new Thread(r, "UrlChecker-" + THREAD_COUNTER.incrementAndGet()); // Thread safety reviewed
            t.setDaemon(true);
            return t;
        }
    });

    private final TimeLimiter timeLimiter;

    public UrlChecker() {
        this(new SimpleTimeLimiter(THREAD_POOL));
    }

    @VisibleForTesting
    UrlChecker(TimeLimiter timeLimiter) {
        this.timeLimiter = timeLimiter;
    }

    public void waitUntilAvailable(long timeout, TimeUnit unit, final URL... urls) throws TimeoutException {
        long start = System.nanoTime();
        log.fine("Waiting for " + Arrays.toString(urls));
        try {
            timeLimiter.callWithTimeout(new Callable<Void>() {
                public Void call() throws InterruptedException {
                    HttpURLConnection connection = null;

                    while (true) {
                        for (URL url : urls) {
                            try {
                                log.fine("Polling " + url);
                                connection = connectToUrl(url);
                                if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                                    return null;
                                }
                            } catch (IOException e) {
                                // Ok, try again.
                            } finally {
                                if (connection != null) {
                                    connection.disconnect();
                                }
                            }
                        }
                        MILLISECONDS.sleep(POLL_INTERVAL_MS);
                    }
                }
            }, timeout, unit, true);
        } catch (UncheckedTimeoutException e) {
            throw new TimeoutException(String.format("Timed out waiting for %s to be available after %d ms",
                    Arrays.toString(urls), MILLISECONDS.convert(System.nanoTime() - start, NANOSECONDS)), e);
        } catch (Exception e) {
            throw Throwables.propagate(e);
        }
    }

    public void waitUntilUnavailable(long timeout, TimeUnit unit, final URL url) throws TimeoutException {
        long start = System.nanoTime();
        log.fine("Waiting for " + url);
        try {
            timeLimiter.callWithTimeout(new Callable<Void>() {
                public Void call() throws InterruptedException {
                    HttpURLConnection connection = null;

                    while (true) {
                        try {
                            log.fine("Polling " + url);
                            connection = connectToUrl(url);
                            if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
                                return null;
                            }
                        } catch (IOException e) {
                            return null;
                        } finally {
                            if (connection != null) {
                                connection.disconnect();
                            }
                        }

                        MILLISECONDS.sleep(POLL_INTERVAL_MS);
                    }
                }
            }, timeout, unit, true);
        } catch (UncheckedTimeoutException e) {
            throw new TimeoutException(String.format("Timed out waiting for %s to become unavailable after %d ms",
                    url, MILLISECONDS.convert(System.nanoTime() - start, NANOSECONDS)), e);
        } catch (Exception e) {
            throw Throwables.propagate(e);
        }
    }

    private HttpURLConnection connectToUrl(URL url) throws IOException {
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setConnectTimeout(CONNECT_TIMEOUT_MS);
        connection.setReadTimeout(READ_TIMEOUT_MS);
        connection.connect();
        return connection;
    }

    public static class TimeoutException extends Exception {
        public TimeoutException(String s, Throwable throwable) {
            super(s, throwable);
        }
    }
}