Merge pull request #163 from soc/topic/java-util-objects

Implement java.util.Objects

classpath/java/util/Arrays.java

@@ -144,6 +144,7 @@ public class Arrays {
 
   public static void sort(Object[] array) {
     sort(array, new Comparator() {
+        @Override
         public int compare(Object a, Object b) {
           return ((Comparable) a).compareTo(b);
         }
@@ -306,14 +307,17 @@ public class Arrays {
 
   public static <T> List<T> asList(final T ... array) {
     return new AbstractList<T>() {
+      @Override
       public int size() {
         return array.length;
       }
 
+      @Override
       public void add(int index, T element) {
         throw new UnsupportedOperationException();
       }
-      
+
+      @Override
       public int indexOf(Object element) {
         for (int i = 0; i < array.length; ++i) {
           if (equal(element, array[i])) {
@@ -323,6 +327,7 @@ public class Arrays {
         return -1;
       }
 
+      @Override
       public int lastIndexOf(Object element) {
         for (int i = array.length - 1; i >= 0; --i) {
           if (equal(element, array[i])) {
@@ -331,19 +336,23 @@ public class Arrays {
         }
         return -1;
       }
-      
+
+      @Override
       public T get(int index) {
         return array[index];
       }
 
+      @Override
       public T set(int index, T value) {
         throw new UnsupportedOperationException();
       }
 
+      @Override
       public T remove(int index) {
         throw new UnsupportedOperationException();
       }
 
+      @Override
       public ListIterator<T> listIterator(int index) {
         return new Collections.ArrayListIterator(this, index);
       }

classpath/java/util/Objects.java

@@ -0,0 +1,64 @@
+package java.util;
+
+public final class Objects {
+  private Objects() {
+    throw new AssertionError("Instantiating java.long.Objetcs is not allowed!");
+  }
+
+  public static <T> int compare(final T x, final T y, final Comparator<? super T> comparator) {
+    if (x == y)
+      return 0;
+    else
+      return comparator.compare(x, y);
+  }
+
+  public static boolean deepEquals(final Object x, final Object y) {
+    if (x == y)
+      return true;
+    if (x == null || y == null)
+      return false;
+    throw new UnsupportedOperationException("deepEquals is not implemented yet.");
+  }
+
+  public static boolean equals(final Object x, final Object y) {
+    if (x == y)
+      return true;
+    if (x != null)
+      return x.equals(y);
+    return false;
+  }
+
+  public static int hash(final Object... values) {
+    return Arrays.hashCode(values);
+  }
+
+  public static int hashCode(final Object value) {
+    if (value == null)
+      return 0;
+    return value.hashCode();
+  }
+
+  public static <T> T requireNonNull(final T value) {
+    if (value == null)
+      throw new NullPointerException();
+    else
+      return value;
+  }
+
+  public static <T> T requireNonNull(final T value, String message) {
+    if (value == null)
+      throw new NullPointerException(message);
+    else
+      return value;
+  }
+
+  public static String toString(final Object value) {
+    return String.valueOf(value);
+  }
+
+  public static String toString(final Object value, final String defaultValue) {
+    if (value == null)
+      return defaultValue;
+    return value.toString();
+  }
+}