remove @nullable from return value for ExpectedConditions that never return null

All these conditions like `presenceOfElementLocated()` either return `WebElement` or throw `TimeoutException`. They never return null.

Fixes #17122

Author: asolntsev

java/src/org/openqa/selenium/support/ui/ExpectedConditions.java

@@ -184,7 +184,7 @@ public String toString() {
    * @param locator used to find the element
    * @return the WebElement once it is located
    */
-  public static ExpectedCondition<@Nullable WebElement> presenceOfElementLocated(final By locator) {
+  public static ExpectedCondition<WebElement> presenceOfElementLocated(final By locator) {
     return new ExpectedCondition<>() {
       @Override
       @Nullable
@@ -245,10 +245,10 @@ public String toString() {
    * @param locator used to find the element
    * @return the list of WebElements once they are located
    */
-  public static ExpectedCondition<@Nullable List<WebElement>> visibilityOfAllElementsLocatedBy(
+  public static ExpectedCondition<List<WebElement>> visibilityOfAllElementsLocatedBy(
       final By locator) {
-    return new ExpectedCondition<@Nullable List<WebElement>>() {
-      private int indexOfInvisibleElement;
+    return new ExpectedCondition<>() {
+      private int indexOfInvisibleElement = -1;
       private @Nullable WebElement invisibleElement;
 
       @Override
@@ -289,7 +289,7 @@ public String toString() {
    * @param elements list of WebElements
    * @return the list of WebElements once they are located
    */
-  public static ExpectedCondition<@Nullable List<WebElement>> visibilityOfAllElements(
+  public static ExpectedCondition<List<WebElement>> visibilityOfAllElements(
       final WebElement... elements) {
     return visibilityOfAllElements(List.of(elements));
   }
@@ -302,10 +302,10 @@ public String toString() {
    * @param elements list of WebElements
    * @return the list of WebElements once they are located
    */
-  public static ExpectedCondition<@Nullable List<WebElement>> visibilityOfAllElements(
+  public static ExpectedCondition<List<WebElement>> visibilityOfAllElements(
       final List<WebElement> elements) {
-    return new ExpectedCondition<@Nullable List<WebElement>>() {
-      private int indexOfInvisibleElement;
+    return new ExpectedCondition<>() {
+      private int indexOfInvisibleElement = -1;
       private @Nullable WebElement invisibleElement;
 
       @Override
@@ -344,8 +344,8 @@ public String toString() {
    * @param element the WebElement
    * @return the (same) WebElement once it is visible
    */
-  public static ExpectedCondition<@Nullable WebElement> visibilityOf(final WebElement element) {
-    return new ExpectedCondition<@Nullable WebElement>() {
+  public static ExpectedCondition<WebElement> visibilityOf(final WebElement element) {
+    return new ExpectedCondition<>() {
       @Override
       public @Nullable WebElement apply(WebDriver driver) {
         return elementIfVisible(element);
@@ -371,9 +371,9 @@ public String toString() {
    * @param locator used to find the element
    * @return the list of WebElements once they are located
    */
-  public static ExpectedCondition<@Nullable List<WebElement>> presenceOfAllElementsLocatedBy(
+  public static ExpectedCondition<List<WebElement>> presenceOfAllElementsLocatedBy(
       final By locator) {
-    return new ExpectedCondition<@Nullable List<WebElement>>() {
+    return new ExpectedCondition<>() {
       @Override
       public @Nullable List<WebElement> apply(WebDriver driver) {
         List<WebElement> elements = driver.findElements(locator);
@@ -594,9 +594,8 @@ public String toString() {
    * @param locator used to find the frame
    * @return WebDriver instance after frame has been switched
    */
-  public static ExpectedCondition<@Nullable WebDriver> frameToBeAvailableAndSwitchToIt(
-      final By locator) {
-    return new ExpectedCondition<@Nullable WebDriver>() {
+  public static ExpectedCondition<WebDriver> frameToBeAvailableAndSwitchToIt(final By locator) {
+    return new ExpectedCondition<>() {
       private @Nullable NotFoundException error;
 
       @Override
@@ -658,9 +657,9 @@ public String toString() {
    * @param frame used to find the frame (web element)
    * @return WebDriver instance after frame has been switched
    */
-  public static ExpectedCondition<@Nullable WebDriver> frameToBeAvailableAndSwitchToIt(
+  public static ExpectedCondition<WebDriver> frameToBeAvailableAndSwitchToIt(
       final WebElement frame) {
-    return new ExpectedCondition<@Nullable WebDriver>() {
+    return new ExpectedCondition<>() {
       private @Nullable NoSuchFrameException error;
 
       @Override
@@ -849,8 +848,8 @@ public String toString() {
    * @param <T> return type of the condition provided
    * @return the result of the provided condition
    */
-  public static <T> ExpectedCondition<@Nullable T> refreshed(final ExpectedCondition<T> condition) {
-    return new ExpectedCondition<@Nullable T>() {
+  public static <T> ExpectedCondition<T> refreshed(final ExpectedCondition<T> condition) {
+    return new ExpectedCondition<>() {
       @Override
       public @Nullable T apply(WebDriver driver) {
         try {
@@ -933,8 +932,8 @@ public String toString() {
     };
   }
 
-  public static ExpectedCondition<@Nullable Alert> alertIsPresent() {
-    return new ExpectedCondition<@Nullable Alert>() {
+  public static ExpectedCondition<Alert> alertIsPresent() {
+    return new ExpectedCondition<>() {
       @Override
       public @Nullable Alert apply(WebDriver driver) {
         try {
@@ -953,7 +952,7 @@ public String toString() {
 
   public static ExpectedCondition<Boolean> numberOfWindowsToBe(final int expectedNumberOfWindows) {
     return new ExpectedCondition<>() {
-      private int actualNumberOfWindows;
+      private int actualNumberOfWindows = -1;
       private @Nullable WebDriverException error;
 
       @Override
@@ -1134,10 +1133,10 @@ public String toString() {
    * @param expectedNumber used to define minimum number of elements
    * @return Boolean true when size of elements list is more than defined
    */
-  public static ExpectedCondition<@Nullable List<WebElement>> numberOfElementsToBeMoreThan(
+  public static ExpectedCondition<List<WebElement>> numberOfElementsToBeMoreThan(
       final By locator, final Integer expectedNumber) {
-    return new ExpectedCondition<@Nullable List<WebElement>>() {
-      private Integer actualNumber = 0;
+    return new ExpectedCondition<>() {
+      private Integer actualNumber = -1;
 
       @Override
       public @Nullable List<WebElement> apply(WebDriver webDriver) {
@@ -1163,10 +1162,10 @@ public String toString() {
    * @param number used to define maximum number of elements
    * @return Boolean true when size of elements list is less than defined
    */
-  public static ExpectedCondition<@Nullable List<WebElement>> numberOfElementsToBeLessThan(
+  public static ExpectedCondition<List<WebElement>> numberOfElementsToBeLessThan(
       final By locator, final Integer number) {
-    return new ExpectedCondition<@Nullable List<WebElement>>() {
-      private Integer currentNumber = 0;
+    return new ExpectedCondition<>() {
+      private Integer currentNumber = -1;
 
       @Override
       public @Nullable List<WebElement> apply(WebDriver webDriver) {
@@ -1191,9 +1190,9 @@ public String toString() {
    * @param expectedNumberOfElements used to define number of elements
    * @return Boolean true when size of elements list is equal to defined
    */
-  public static ExpectedCondition<@Nullable List<WebElement>> numberOfElementsToBe(
+  public static ExpectedCondition<List<WebElement>> numberOfElementsToBe(
       final By locator, final Integer expectedNumberOfElements) {
-    return new ExpectedCondition<@Nullable List<WebElement>>() {
+    return new ExpectedCondition<>() {
       private Integer actualNumberOfElements = -1;
 
       @Override
@@ -1412,9 +1411,9 @@ private static Optional<String> getAttributeOrCssValue(WebElement element, Strin
    * @param childLocator used to find the child elements.
    * @return visible nested element
    */
-  public static ExpectedCondition<@Nullable List<WebElement>> visibilityOfNestedElementsLocatedBy(
+  public static ExpectedCondition<List<WebElement>> visibilityOfNestedElementsLocatedBy(
       final By parent, final By childLocator) {
-    return new ExpectedCondition<@Nullable List<WebElement>>() {
+    return new ExpectedCondition<>() {
       private int indexOfInvisibleElement = -1;
       private @Nullable WebElement invisibleChild;
 
@@ -1463,9 +1462,9 @@ public String toString() {
    *     By.xpath("./tr/td")}.
    * @return visible sub-element
    */
-  public static ExpectedCondition<@Nullable List<WebElement>> visibilityOfNestedElementsLocatedBy(
+  public static ExpectedCondition<List<WebElement>> visibilityOfNestedElementsLocatedBy(
       final WebElement element, final By childLocator) {
-    return new ExpectedCondition<@Nullable List<WebElement>>() {
+    return new ExpectedCondition<>() {
       private int indexOfInvisibleElement = -1;
       private @Nullable WebElement invisibleChild;
 
@@ -1513,7 +1512,7 @@ public String toString() {
    *     By.xpath("./tr/td")}.
    * @return sub-element
    */
-  public static ExpectedCondition<@Nullable WebElement> presenceOfNestedElementLocatedBy(
+  public static ExpectedCondition<WebElement> presenceOfNestedElementLocatedBy(
       final By locator, final By childLocator) {
     return new ExpectedCondition<>() {
 
@@ -1543,7 +1542,7 @@ public String toString() {
    *     By.xpath("./tr/td")}.
    * @return sub-element
    */
-  public static ExpectedCondition<@Nullable WebElement> presenceOfNestedElementLocatedBy(
+  public static ExpectedCondition<WebElement> presenceOfNestedElementLocatedBy(
       final WebElement element, final By childLocator) {
 
     return new ExpectedCondition<>() {
@@ -1573,9 +1572,9 @@ public String toString() {
    *     By.xpath("./tr/td")}.
    * @return sub-element
    */
-  public static ExpectedCondition<@Nullable List<WebElement>> presenceOfNestedElementsLocatedBy(
+  public static ExpectedCondition<List<WebElement>> presenceOfNestedElementsLocatedBy(
       final By parent, final By childLocator) {
-    return new ExpectedCondition<@Nullable List<WebElement>>() {
+    return new ExpectedCondition<>() {
 
       @Override
       public @Nullable List<WebElement> apply(WebDriver driver) {
@@ -1610,7 +1609,7 @@ public static ExpectedCondition<Boolean> invisibilityOfAllElements(final WebElem
   public static ExpectedCondition<Boolean> invisibilityOfAllElements(
       final List<WebElement> elements) {
     return new ExpectedCondition<>() {
-      private int indexOfVisibleElement;
+      private int indexOfVisibleElement = -1;
       private @Nullable WebElement visibleElement;
 
       @Override
@@ -1807,8 +1806,8 @@ public String toString() {
    * @param javaScript as executable js line
    * @return object once JavaScript executes without errors
    */
-  public static ExpectedCondition<@Nullable Object> jsReturnsValue(final String javaScript) {
-    return new ExpectedCondition<@Nullable Object>() {
+  public static ExpectedCondition<Object> jsReturnsValue(final String javaScript) {
+    return new ExpectedCondition<>() {
       private @Nullable WebDriverException error;
 
       @Override