Changeset 10040 in josm for trunk/src/org/openstreetmap/josm/tools/Predicates.java

Timestamp:

2016-03-26T11:30:54+01:00 (8 years ago)

Author:

Don-vip

Message:

fix #12680 - Documentation and cleanup on predicates (patch by michael2402, modified)

File:

• trunk/src/org/openstreetmap/josm/tools/Predicates.java (modified) (2 diffs)

trunk/src/org/openstreetmap/josm/tools/Predicates.java

@@ -14 +14 @@
 
     private Predicates() {
+    }
+
+    /**
+     * Creates a predicate that returns true every time.
+     * @param <T> The type of the predicate.
+     * @return A predicate returning <code>true</code>
+     * @since 10040
+     */
+    public static <T> Predicate<T> alwaysTrue() {
+        return new Predicate<T>() {
+            @Override
+            public boolean evaluate(T object) {
+                return true;
+            }
+        };
+    }
+
+    /**
+     * Creates a predicate that returns false every time.
+     * @param <T> The type of the predicate.
+     * @return A predicate returning <code>false</code>
+     * @since 10040
+     */
+    public static <T> Predicate<T> alwaysFalse() {
+        return new Predicate<T>() {
+            @Override
+            public boolean evaluate(T object) {
+                return false;
+            }
+        };
     }
 
@@ -42 +72 @@
             public boolean evaluate(T obj) {
                 return Objects.equals(obj, ref);
+            }
+        };
+    }
+
+    /**
+     * Creates a new predicate that checks if elements are exactly of that class.
+     * @param <T> The predicate type.
+     * @param clazz The class the elements must have.
+     * @return A predicate.
+     */
+    public static <T> Predicate<T> isOfClass(final Class<? extends T> clazz) {
+        return new Predicate<T>() {
+            @Override
+            public boolean evaluate(T obj) {
+                return obj != null && obj.getClass() == clazz;
             }
         };