introduce constant()

platform/util-rt/src/com/intellij/openapi/util/Conditions.java

@@ -45,6 +45,10 @@ public class Conditions {
     return (Condition<T>)Condition.NOT_NULL;
   }
 
+  public static <T> Condition<T> constant(boolean value) {
+    return (Condition<T>)(value ? TRUE : FALSE);
+  }
+
   public static <T> Condition<T> instanceOf(final Class<?> clazz) {
     return new Condition<T>() {
       @Override

platform/util-rt/src/com/intellij/util/Functions.java

@@ -29,6 +29,15 @@ public class Functions {
     return (Function.Mono<A>)Function.ID;
   }
 
+  public static <A, B> Function<A, B> constant(final B b) {
+    return new Function<A, B>() {
+      @Override
+      public B fun(A a) {
+        return b;
+      }
+    };
+  }
+
   public static <A, B> Function<A, B> identity() {
     return Function.ID;
   }