add comments for selenium driver

webmagic-plugin/webmagic-selenium/src/main/java/us/codecraft/webmagic/selenium/downloader/SeleniumDownloader.java

@@ -82,7 +82,6 @@ public class SeleniumDownloader implements Downloader, Destroyable {
         }
         WebElement webElement = webDriver.findElement(By.xpath("/html"));
         String content = webElement.getAttribute("outerHTML");
-        //
         Page page = new Page();
         page.setHtml(new Html(UrlUtils.fixAllRelativeHrefs(content, request.getUrl())));
         page.setUrl(new PlainText(request.getUrl()));

webmagic-plugin/webmagic-selenium/src/main/java/us/codecraft/webmagic/selenium/downloader/WebDriverPool.java

@@ -27,8 +27,16 @@ class WebDriverPool {
 
     private AtomicInteger stat = new AtomicInteger(STAT_RUNNING);
 
+    /**
+     * store webDrivers created
+     */
     private List<WebDriver> webDriverList = Collections.synchronizedList(new ArrayList<WebDriver>());
 
+    /**
+     * store webDrivers available
+     */
+    private BlockingDeque<WebDriver> innerQueue = new LinkedBlockingDeque<WebDriver>();
+
     public WebDriverPool(int capacity) {
         this.capacity = capacity;
     }
@@ -37,8 +45,6 @@ class WebDriverPool {
         this(DEFAULT_CAPACITY);
     }
 
-    private BlockingDeque<WebDriver> innerQueue = new LinkedBlockingDeque<WebDriver>();
-
     public WebDriver get() throws InterruptedException {
         checkRunning();
         WebDriver poll = innerQueue.poll();