Refactor Bys, "checkNotNull"

Move the checks to the constructors of the
concrete classes (which are in the public API).

Also, some minor cleanups.

Signed-off-by: Simon Stewart <[email protected]>

Author: alb-i986

java/client/src/org/openqa/selenium/By.java

@@ -49,10 +49,6 @@ public abstract class By {
    * @return A By which locates elements by the value of the "id" attribute.
    */
   public static By id(final String id) {
-    if (id == null)
-      throw new IllegalArgumentException(
-          "Cannot find elements when the id is null.");
-
     return new ById(id);
   }
 
@@ -61,58 +57,38 @@ public static By id(final String id) {
    * @return A By which locates A elements by the exact text they display.
    */
   public static By linkText(final String linkText) {
-    if (linkText == null)
-      throw new IllegalArgumentException(
-          "Cannot find elements when the link text is null.");
-
     return new ByLinkText(linkText);
   }
 
   /**
-   * @param linkText The text to match against.
-   * @return A By which locates A elements that contain the given text.
+   * @param partialLinkText The partial text to match against
+   * @return a By which locates A elements that contain the given link text
    */
-  public static By partialLinkText(final String linkText) {
-    if (linkText == null)
-      throw new IllegalArgumentException(
-          "Cannot find elements when the link text is null.");
-
-    return new ByPartialLinkText(linkText);
+  public static By partialLinkText(final String partialLinkText) {
+    return new ByPartialLinkText(partialLinkText);
   }
 
   /**
    * @param name The value of the "name" attribute to search for.
    * @return A By which locates elements by the value of the "name" attribute.
    */
   public static By name(final String name) {
-    if (name == null)
-      throw new IllegalArgumentException(
-          "Cannot find elements when the name is null.");
-
     return new ByName(name);
   }
 
   /**
-   * @param name The element's tag name.
-   * @return A By which locates elements by their tag name.
+   * @param tagName The element's tagName
+   * @return a By which locates elements by their tag name
    */
-  public static By tagName(final String name) {
-    if (name == null)
-      throw new IllegalArgumentException(
-          "Cannot find elements when the tag name is null.");
-
-    return new ByTagName(name);
+  public static By tagName(final String tagName) {
+    return new ByTagName(tagName);
   }
 
   /**
    * @param xpathExpression The XPath to use.
    * @return A By which locates elements via XPath.
    */
   public static By xpath(final String xpathExpression) {
-    if (xpathExpression == null)
-      throw new IllegalArgumentException(
-          "Cannot find elements when the XPath is null.");
-
     return new ByXPath(xpathExpression);
   }
 
@@ -125,10 +101,6 @@ public static By xpath(final String xpathExpression) {
    * @return A By which locates elements by the value of the "class" attribute.
    */
   public static By className(final String className) {
-    if (className == null)
-      throw new IllegalArgumentException(
-          "Cannot find elements when the class name is null.");
-
     return new ByClassName(className);
   }
 
@@ -137,16 +109,11 @@ public static By className(final String className) {
    * implement the Selector API, a best effort is made to emulate the API. In this case, we strive
    * for at least CSS2 support, but offer no guarantees.
    *
-   * @param selector CSS expression.
+   * @param cssSelector CSS expression.
    * @return A By which locates elements by CSS.
    */
-  public static By cssSelector(final String selector) {
-    if (selector == null)
-      throw new IllegalArgumentException(
-          "Cannot find elements when the CSS selector is null.");
-
-    return new ByCssSelector(selector);
-
+  public static By cssSelector(final String cssSelector) {
+    return new ByCssSelector(cssSelector);
   }
 
   /**
@@ -201,6 +168,10 @@ public static class ById extends By implements Serializable {
     private final String id;
 
     public ById(String id) {
+      if (id == null)
+        throw new IllegalArgumentException(
+          "Cannot find elements with a null id attribute.");
+
       this.id = id;
     }
 
@@ -233,6 +204,10 @@ public static class ByLinkText extends By implements Serializable {
     private final String linkText;
 
     public ByLinkText(String linkText) {
+      if (linkText == null)
+        throw new IllegalArgumentException(
+          "Cannot find elements when link text is null.");
+
       this.linkText = linkText;
     }
 
@@ -256,26 +231,30 @@ public static class ByPartialLinkText extends By implements Serializable {
 
     private static final long serialVersionUID = 1163955344140679054L;
 
-    private final String linkText;
+    private final String partialLinkText;
 
-    public ByPartialLinkText(String linkText) {
-      this.linkText = linkText;
+    public ByPartialLinkText(String partialLinkText) {
+      if (partialLinkText == null)
+        throw new IllegalArgumentException(
+          "Cannot find elements when link text is null.");
+
+      this.partialLinkText = partialLinkText;
     }
 
     @Override
     public List<WebElement> findElements(SearchContext context) {
       return ((FindsByLinkText) context)
-          .findElementsByPartialLinkText(linkText);
+          .findElementsByPartialLinkText(partialLinkText);
     }
 
     @Override
     public WebElement findElement(SearchContext context) {
-      return ((FindsByLinkText) context).findElementByPartialLinkText(linkText);
+      return ((FindsByLinkText) context).findElementByPartialLinkText(partialLinkText);
     }
 
     @Override
     public String toString() {
-      return "By.partialLinkText: " + linkText;
+      return "By.partialLinkText: " + partialLinkText;
     }
   }
 
@@ -286,6 +265,10 @@ public static class ByName extends By implements Serializable {
     private final String name;
 
     public ByName(String name) {
+      if (name == null)
+        throw new IllegalArgumentException(
+          "Cannot find elements when name text is null.");
+
       this.name = name;
     }
 
@@ -315,29 +298,33 @@ public static class ByTagName extends By implements Serializable {
 
     private static final long serialVersionUID = 4699295846984948351L;
 
-    private final String name;
+    private final String tagName;
 
-    public ByTagName(String name) {
-      this.name = name;
+    public ByTagName(String tagName) {
+      if (tagName == null)
+        throw new IllegalArgumentException(
+          "Cannot find elements when name tag name is null.");
+
+      this.tagName = tagName;
     }
 
     @Override
     public List<WebElement> findElements(SearchContext context) {
       if (context instanceof FindsByTagName)
-        return ((FindsByTagName) context).findElementsByTagName(name);
-      return ((FindsByXPath) context).findElementsByXPath(".//" + name);
+        return ((FindsByTagName) context).findElementsByTagName(tagName);
+      return ((FindsByXPath) context).findElementsByXPath(".//" + tagName);
     }
 
     @Override
     public WebElement findElement(SearchContext context) {
       if (context instanceof FindsByTagName)
-        return ((FindsByTagName) context).findElementByTagName(name);
-      return ((FindsByXPath) context).findElementByXPath(".//" + name);
+        return ((FindsByTagName) context).findElementByTagName(tagName);
+      return ((FindsByXPath) context).findElementByXPath(".//" + tagName);
     }
 
     @Override
     public String toString() {
-      return "By.tagName: " + name;
+      return "By.tagName: " + tagName;
     }
   }
 
@@ -348,6 +335,10 @@ public static class ByXPath extends By implements Serializable {
     private final String xpathExpression;
 
     public ByXPath(String xpathExpression) {
+      if (xpathExpression == null)
+        throw new IllegalArgumentException(
+          "Cannot find elements when the XPath expression is null.");
+
       this.xpathExpression = xpathExpression;
     }
 
@@ -374,6 +365,10 @@ public static class ByClassName extends By implements Serializable {
     private final String className;
 
     public ByClassName(String className) {
+      if (className == null)
+        throw new IllegalArgumentException(
+          "Cannot find elements when the class name expression is null.");
+
       this.className = className;
     }
 
@@ -417,37 +412,41 @@ public static class ByCssSelector extends By implements Serializable {
 
     private static final long serialVersionUID = -3910258723099459239L;
 
-    private final String selector;
+    private final String cssSelector;
 
-    public ByCssSelector(String selector) {
-      this.selector = selector;
+    public ByCssSelector(String cssSelector) {
+      if (cssSelector == null)
+        throw new IllegalArgumentException(
+          "Cannot find elements when the selector is null");
+      
+      this.cssSelector = cssSelector;
     }
 
     @Override
     public WebElement findElement(SearchContext context) {
       if (context instanceof FindsByCssSelector) {
         return ((FindsByCssSelector) context)
-            .findElementByCssSelector(selector);
+            .findElementByCssSelector(cssSelector);
       }
 
       throw new WebDriverException(
-          "Driver does not support finding an element by selector: " + selector);
+          "Driver does not support finding an element by selector: " + cssSelector);
     }
 
     @Override
     public List<WebElement> findElements(SearchContext context) {
       if (context instanceof FindsByCssSelector) {
         return ((FindsByCssSelector) context)
-            .findElementsByCssSelector(selector);
+            .findElementsByCssSelector(cssSelector);
       }
 
       throw new WebDriverException(
-          "Driver does not support finding elements by selector: " + selector);
+          "Driver does not support finding elements by selector: " + cssSelector);
     }
 
     @Override
     public String toString() {
-      return "By.cssSelector: " + selector;
+      return "By.cssSelector: " + cssSelector;
     }
   }
 }