extract matches method from MatchFinder:

Instead of inheritance by overriding matches, use composition of
a predicate.

organize imports.

Change-Id: I1aa95cb14822fb27151cda8bdffd61580b49c5e3

6 files changed, 63 insertions, 51 deletions

diff --git a/src/com/google/android/droiddriver/finders/By.java b/src/com/google/android/droiddriver/finders/By.java
index 152369a..0a4eee9 100644
--- a/src/com/google/android/droiddriver/finders/By.java
+++ b/src/com/google/android/droiddriver/finders/By.java
@@ -22,6 +22,11 @@ import com.google.android.droiddriver.UiElement;
 import com.google.common.annotations.Beta;
 import com.google.common.base.Joiner;
 import com.google.common.base.Objects;
+import com.google.common.base.Predicate;
+import com.google.common.base.Predicates;
+import com.google.common.collect.Lists;
+
+import java.util.List;
 
 /**
  * Convenience methods to create commonly used finders.
@@ -223,6 +228,15 @@ public class By {
     return new ChainFinder(parent, child);
   }
 
+  private static List<Predicate<? super UiElement>> getPredicates(MatchFinder... finders) {
+    List<Predicate<? super UiElement>> predicates =
+        Lists.newArrayListWithExpectedSize(finders.length);
+    for (MatchFinder finder : finders) {
+      predicates.add(finder.predicate);
+    }
+    return predicates;
+  }
+
   // Hamcrest style finder aggregators
   /**
    * Evaluates given {@finders} in short-circuit fashion in the order
@@ -233,17 +247,7 @@ public class By {
    * @return a finder that is the logical conjunction of given finders
    */
   public static MatchFinder allOf(final MatchFinder... finders) {
-    return new MatchFinder() {
-      @Override
-      public boolean matches(UiElement element) {
-        for (MatchFinder finder : finders) {
-          if (!finder.matches(element)) {
-            return false;
-          }
-        }
-        return true;
-      }
-
+    return new MatchFinder(Predicates.and(getPredicates(finders))) {
       @Override
       public String toString() {
         return "allOf(" + Joiner.on(",").join(finders) + ")";
@@ -260,17 +264,7 @@ public class By {
    * @return a finder that is the logical disjunction of given finders
    */
   public static MatchFinder anyOf(final MatchFinder... finders) {
-    return new MatchFinder() {
-      @Override
-      public boolean matches(UiElement element) {
-        for (MatchFinder finder : finders) {
-          if (finder.matches(element)) {
-            return true;
-          }
-        }
-        return false;
-      }
-
+    return new MatchFinder(Predicates.or(getPredicates(finders))) {
       @Override
       public String toString() {
         return "anyOf(" + Joiner.on(",").join(finders) + ")";
@@ -284,13 +278,13 @@ public class By {
    */
   public static MatchFinder withParent(final MatchFinder parentFinder) {
     checkNotNull(parentFinder);
-    return new MatchFinder() {
+    return new MatchFinder(new Predicate<UiElement>() {
       @Override
-      public boolean matches(UiElement element) {
+      public boolean apply(UiElement element) {
         UiElement parent = element.getParent();
         return parent != null && parentFinder.matches(parent);
       }
-
+    }) {
       @Override
       public String toString() {
         return "withParent(" + parentFinder + ")";
@@ -304,9 +298,9 @@ public class By {
    */
   public static MatchFinder withAncestor(final MatchFinder ancestorFinder) {
     checkNotNull(ancestorFinder);
-    return new MatchFinder() {
+    return new MatchFinder(new Predicate<UiElement>() {
       @Override
-      public boolean matches(UiElement element) {
+      public boolean apply(UiElement element) {
         UiElement parent = element.getParent();
         while (parent != null) {
           if (ancestorFinder.matches(parent)) {
@@ -316,7 +310,7 @@ public class By {
         }
         return false;
       }
-
+    }) {
       @Override
       public String toString() {
         return "withAncestor(" + ancestorFinder + ")";
@@ -330,9 +324,9 @@ public class By {
    */
   public static MatchFinder withSibling(final MatchFinder siblingFinder) {
     checkNotNull(siblingFinder);
-    return new MatchFinder() {
+    return new MatchFinder(new Predicate<UiElement>() {
       @Override
-      public boolean matches(UiElement element) {
+      public boolean apply(UiElement element) {
         UiElement parent = element.getParent();
         if (parent == null) {
           return false;
@@ -345,7 +339,7 @@ public class By {
         }
         return false;
       }
-
+    }) {
       @Override
       public String toString() {
         return "withSibling(" + siblingFinder + ")";
diff --git a/src/com/google/android/droiddriver/finders/ByAttribute.java b/src/com/google/android/droiddriver/finders/ByAttribute.java
index d7d8689..3356533 100644
--- a/src/com/google/android/droiddriver/finders/ByAttribute.java
+++ b/src/com/google/android/droiddriver/finders/ByAttribute.java
@@ -18,6 +18,7 @@ package com.google.android.droiddriver.finders;
 import static com.google.common.base.Preconditions.checkNotNull;
 
 import com.google.android.droiddriver.UiElement;
+import com.google.common.base.Predicate;
 
 /**
  * Matches UiElement by a single attribute.
@@ -27,20 +28,22 @@ public class ByAttribute<T> extends MatchFinder {
   private final MatchStrategy<? super T> strategy;
   private final T expected;
 
-  protected ByAttribute(Attribute attribute, MatchStrategy<? super T> strategy, T expected) {
+  protected ByAttribute(final Attribute attribute, final MatchStrategy<? super T> strategy,
+      final T expected) {
+    super(new Predicate<UiElement>() {
+      @Override
+      public boolean apply(UiElement element) {
+        T value = attribute.getValue(element);
+        return strategy.match(expected, value);
+      }
+    });
     this.attribute = checkNotNull(attribute);
     this.strategy = checkNotNull(strategy);
     this.expected = checkNotNull(expected);
   }
 
   @Override
-  public boolean matches(UiElement element) {
-    T value = attribute.getValue(element);
-    return strategy.match(expected, value);
-  }
-
-  @Override
   public String toString() {
-    return String.format("ByAttribute{%s %s %s}", attribute, strategy, expected);
+    return String.format("{%s %s %s}", attribute, strategy, expected);
   }
 }
diff --git a/src/com/google/android/droiddriver/finders/MatchFinder.java b/src/com/google/android/droiddriver/finders/MatchFinder.java
index 2818fde..33fe699 100644
--- a/src/com/google/android/droiddriver/finders/MatchFinder.java
+++ b/src/com/google/android/droiddriver/finders/MatchFinder.java
@@ -21,20 +21,23 @@ import android.util.Log;
 import com.google.android.droiddriver.UiElement;
 import com.google.android.droiddriver.exceptions.ElementNotFoundException;
 import com.google.android.droiddriver.util.Logs;
+import com.google.common.base.Predicate;
+import com.google.common.base.Predicates;
 
 /**
  * Traverses the UiElement tree and returns the first UiElement satisfying
- * {@link #matches(UiElement)}.
+ * {@link #predicate}.
  */
 public abstract class MatchFinder implements Finder {
-  /**
-   * Returns true if the {@code element} matches the implementing finder. The
-   * implementing finder should not poll.
-   *
-   * @param element The element to validate against
-   * @return true if the element matches
-   */
-  public abstract boolean matches(UiElement element);
+  protected final Predicate<? super UiElement> predicate;
+
+  protected MatchFinder(Predicate<? super UiElement> predicate) {
+    if (predicate == null) {
+      this.predicate = Predicates.alwaysTrue();
+    } else {
+      this.predicate = predicate;
+    }
+  }
 
   /**
    * {@inheritDoc}
@@ -61,4 +64,16 @@ public abstract class MatchFinder implements Finder {
     }
     throw new ElementNotFoundException(this);
   }
+
+  /**
+   * Returns true if the {@code element} matches this finder. This can be used
+   * to test the exact match of {@code element} when this finder is used in
+   * {@link By#anyOf(MatchFinder...)}.
+   *
+   * @param element The element to validate against
+   * @return true if the element matches
+   */
+  public final boolean matches(UiElement element) {
+    return predicate.apply(element);
+  }
 }
diff --git a/src/com/google/android/droiddriver/scroll/AbstractSentinelStrategy.java b/src/com/google/android/droiddriver/scroll/AbstractSentinelStrategy.java
index 345725f..b197b43 100644
--- a/src/com/google/android/droiddriver/scroll/AbstractSentinelStrategy.java
+++ b/src/com/google/android/droiddriver/scroll/AbstractSentinelStrategy.java
@@ -21,8 +21,8 @@ import com.google.android.droiddriver.exceptions.ElementNotFoundException;
 import com.google.android.droiddriver.finders.By;
 import com.google.android.droiddriver.finders.Finder;
 import com.google.android.droiddriver.scroll.Direction.LogicalDirection;
-import com.google.android.droiddriver.scroll.Direction.PhysicalToLogicalConverter;
 import com.google.android.droiddriver.scroll.Direction.PhysicalDirection;
+import com.google.android.droiddriver.scroll.Direction.PhysicalToLogicalConverter;
 import com.google.common.base.Predicate;
 import com.google.common.base.Predicates;
 
diff --git a/src/com/google/android/droiddriver/scroll/DynamicSentinelStrategy.java b/src/com/google/android/droiddriver/scroll/DynamicSentinelStrategy.java
index 3dca121..9dc1e3a 100644
--- a/src/com/google/android/droiddriver/scroll/DynamicSentinelStrategy.java
+++ b/src/com/google/android/droiddriver/scroll/DynamicSentinelStrategy.java
@@ -21,8 +21,8 @@ import com.google.android.droiddriver.DroidDriver;
 import com.google.android.droiddriver.UiElement;
 import com.google.android.droiddriver.exceptions.ElementNotFoundException;
 import com.google.android.droiddriver.finders.Finder;
-import com.google.android.droiddriver.scroll.Direction.PhysicalToLogicalConverter;
 import com.google.android.droiddriver.scroll.Direction.PhysicalDirection;
+import com.google.android.droiddriver.scroll.Direction.PhysicalToLogicalConverter;
 import com.google.android.droiddriver.util.Logs;
 import com.google.common.base.Objects;
 
diff --git a/src/com/google/android/droiddriver/scroll/StaticSentinelStrategy.java b/src/com/google/android/droiddriver/scroll/StaticSentinelStrategy.java
index e9225aa..844f0e9 100644
--- a/src/com/google/android/droiddriver/scroll/StaticSentinelStrategy.java
+++ b/src/com/google/android/droiddriver/scroll/StaticSentinelStrategy.java
@@ -21,8 +21,8 @@ import com.google.android.droiddriver.DroidDriver;
 import com.google.android.droiddriver.UiElement;
 import com.google.android.droiddriver.finders.Finder;
 import com.google.android.droiddriver.instrumentation.InstrumentationDriver;
-import com.google.android.droiddriver.scroll.Direction.PhysicalToLogicalConverter;
 import com.google.android.droiddriver.scroll.Direction.PhysicalDirection;
+import com.google.android.droiddriver.scroll.Direction.PhysicalToLogicalConverter;
 
 /**
  * Determines whether scrolling is possible by checking whether the last child