laurens/rust_the_book
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

state_pattern_oop: Only allow change of contents in Draft state

Browse source
This commit is contained in:
laurens 2020-10-11 16:39:40 +02:00
parent 3aa19cc04b
commit 592bbea29e
1 changed files with 15 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

16
state_pattern_oop/src/main.rs
View file

@ -14,7 +14,9 @@ impl Post {
} }
pub fn add_text(&mut self, text: &str) { pub fn add_text(&mut self, text: &str) {
self.content.push_str(text); if self.state.as_ref().unwrap().is_text_adjust_allowed() {
self.content.push_str(text);
}
} }
pub fn content(&self) -> &str { pub fn content(&self) -> &str {
@ -42,6 +44,10 @@ trait State {
fn content<'a>(&self, _post: &'a Post) -> &'a str { fn content<'a>(&self, _post: &'a Post) -> &'a str {
"" ""
} }
fn is_text_adjust_allowed(&self) -> bool {
false
}
} }
struct Draft {} struct Draft {}
@ -58,6 +64,10 @@ impl State for Draft {
fn reject(self: Box<Self>) -> Box<dyn State> { fn reject(self: Box<Self>) -> Box<dyn State> {
self self
} }
fn is_text_adjust_allowed(&self) -> bool {
true
}
} }
struct PendingReview { struct PendingReview {
@ -119,6 +129,7 @@ fn main() {
post.approve(); // Shouldn't cause approval to go forward! post.approve(); // Shouldn't cause approval to go forward!
post.request_review(); post.request_review();
post.add_text("I ate a burger for lunch today"); //Shouldn't do anything
assert_eq!("", post.content()); assert_eq!("", post.content());
post.approve(); // First valid approval, we need two so the content should still be empty post.approve(); // First valid approval, we need two so the content should still be empty
@ -126,4 +137,7 @@ fn main() {
post.approve(); // Last approval post.approve(); // Last approval
assert_eq!("I ate a salad for lunch today", post.content()); assert_eq!("I ate a salad for lunch today", post.content());
post.add_text("I ate nothing for lunch today"); //Shouldn't do anything
assert_eq!("I ate a salad for lunch today", post.content());
} }