More null safe operations

Author: winterbe

src/com/winterbe/java8/Take.java

@@ -2,6 +2,7 @@
 
 import java.util.Optional;
 import java.util.function.Function;
+import java.util.function.Supplier;
 
 /**
  * Simplified elvis-like operator. You can achieve the same with Optional but Take has simpler syntax.
@@ -19,15 +20,25 @@ private Take(T value) {
  this.value = value;
  }
 
+ public static <T> Optional<T> of(Supplier<T> resolver) {
+ try {
+ T result = resolver.get();
+ return Optional.ofNullable(result);
+ }
+ catch (NullPointerException e) {
+ return Optional.empty();
+ }
+ }
+
  public static <T> Take<T> of(T something) {
  return new Take<>(something);
  }
 
- public <S> Take<S> take(Function<? super T, S> mapper) {
+ public <S> Take<S> take(Function<? super T, S> resolver) {
  if (!isPresent()) {
  return empty();
  }
- S result = mapper.apply(value);
+ S result = resolver.apply(value);
  return new Take<>(result);
  }
 

src/com/winterbe/java8/TakeTest.java

@@ -40,7 +40,21 @@ public static void main(String[] args) {
  .take(Inner::getFoo)
  .get();
 
- System.out.println(optional.get());
+ System.out.println(optional.isPresent());
+
+ something.getNested().inner = null;
+ Optional<String> optional2 = Take.of(() ->
+ something.getNested().getInner().getFoo());
+ System.out.println(optional2.isPresent());
+
+
+ String x = null;
+ String y = "boo";
+ String z = Take.of(x).orElse(y);
+
+ System.out.println(z);
+
+
  }
 
 }