stratozero opened a new pull request, #1455:
URL: https://github.com/apache/commons-lang/pull/1455
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Thanks for your contribution to [Apache
Commons](https://commons.apache.org/)! Your help is appreciated!
This PR introduces two new utility methods in `ObjectUtils` to reduce
boilerplate
when executing an action only if an object is not null.
### Rationale
- Currently, developers either write explicit null checks or use
`Optional.ofNullable(obj).ifPresent(...)`.
- `Optional` adds readability but creates an extra object which is
unnecessary
for simple null-guarded operations.
- Usual null check is prone to the error of calling a getter method twice,
(like `if (obj.getX() != null) consume(obj.getX())`), a pattern seen many times
in a lot of projects, which is an error in many ways:
- causes twice the access to the property
- potentially doubles the side effects
- can be a partial guard as it actually does not prevent the getter to
return null in the second call
- A static utility method in `ObjectUtils` makes the intent clearer and
avoids
extra allocations.
### Proposed API
```java
public static <T> void ifNotNull(T obj, Consumer<? super T> action) {
if (obj != null) {
action.accept(obj);
}
}
```
The proposed API could then be used like `ifNotNull(obj.getX(), x ->
consume(x))` preventing the creation of an unnecessary Optional and avoiding
the possibility of accessing a property twice.
Also, to accomplish the task of not allocating extra objects, we need to
take care of injecting some context as a parameter (to avoid capturing lambdas):
``` java
public static <T, C> void ifNotNull(T obj, C ctx, BiConsumer<? super T, ?
super C> action) {
if (obj != null) {
action.accept(obj, ctx);
}
}
```
So that it becomes possible to write `ifNotNull(obj.getX(), this, (x, ctx)
-> XType::setContext)`
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