2.6.2: Add Backstack.canSetScopeProviders()`

Author: Zhuinden

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Change log
 
+-Simple Stack 2.6.2 (2021-06-07)
+--------------------------------
+
+- ADDED: `Backstack.canSetScopeProviders()`.
+
+This is in conjunction with the 2.6.1 change, while making it safe to use them without extra checks such as `if(lastNonConfigurationInstance == null) {`.
+
 -Simple Stack 2.6.1 (2021-05-03)
 --------------------------------
 

README.md

@@ -49,15 +49,15 @@ and then, add the dependency to your module's `build.gradle.kts` (or `build.grad
 
 ``` kotlin
 // build.gradle.kts
-implementation("com.github.Zhuinden:simple-stack:2.6.1")
+implementation("com.github.Zhuinden:simple-stack:2.6.2")
 implementation("com.github.Zhuinden:simple-stack-extensions:2.2.1")
 ```
 
 or
 
 ``` groovy
 // build.gradle
-implementation 'com.github.Zhuinden:simple-stack:2.6.1'
+implementation 'com.github.Zhuinden:simple-stack:2.6.2'
 implementation 'com.github.Zhuinden:simple-stack-extensions:2.2.1'
 ```
 

simple-stack/src/main/java/com/zhuinden/simplestack/Backstack.java

@@ -242,15 +242,26 @@ public void setStateClearStrategy(@Nonnull StateClearStrategy stateClearStrategy
         this.stateClearStrategy = stateClearStrategy;
     }
 
+    /**
+     * Specifies if setting a scope provider, such as either {@link Backstack#setScopedServices(ScopedServices)} or {@link Backstack#setGlobalServices(GlobalServices)} is allowed.
+     * <p>
+     * This can be useful in case of deferred initialization, as scope providers shouldn't be set and aren't allowed once the initial state change happens.
+     *
+     * @return true if scope provider can be set
+     */
+    public final boolean canSetScopeProviders() {
+        return !didRunInitialStateChange;
+    }
+
     /**
      * Specifies a {@link ScopedServices} to allow handling the creation of scoped services.
      * <p>
-     * Must be called before the initial state change.
+     * Must be called before the initial state change. Call {@link Backstack#canSetScopeProviders()} to see if it's allowed.
      *
      * @param scopedServices the {@link ScopedServices}.
      */
     public void setScopedServices(@Nonnull ScopedServices scopedServices) {
-        if(didRunInitialStateChange) {
+        if(!canSetScopeProviders()) {
             throw new IllegalStateException("Scope provider should be set before the initial state change!");
         }
         if(scopedServices == null) {
@@ -262,14 +273,14 @@ public void setScopedServices(@Nonnull ScopedServices scopedServices) {
     /**
      * Specifies a {@link GlobalServices} that describes the services of the global scope.
      *
-     * Must be called before the initial state change.
+     * Must be called before the initial state change. Call {@link Backstack#canSetScopeProviders()} to see if it's allowed.
      *
      * Please note that setting a {@link GlobalServices.Factory} overrides this configuration option.
      *
      * @param globalServices the {@link GlobalServices}.
      */
     public void setGlobalServices(@Nonnull GlobalServices globalServices) {
-        if(didRunInitialStateChange) {
+        if(!canSetScopeProviders()) {
             throw new IllegalStateException("Scope provider should be set before the initial state change!");
         }
         if(globalServices == null) {
@@ -281,7 +292,7 @@ public void setGlobalServices(@Nonnull GlobalServices globalServices) {
     /**
      * Specifies a {@link GlobalServices.Factory} that describes the services of the global scope that are deferred until first creation.
      *
-     * Must be called before the initial state change.
+     * Must be called before the initial state change. Call {@link Backstack#canSetScopeProviders()} to see if it's allowed.
      *
      * Please note that a strong reference is kept to the factory, and the {@link Backstack} is typically preserved across configuration change.
      * It is recommended that it is NOT an anonymous inner class or normal inner class in an Activity,
@@ -292,7 +303,7 @@ public void setGlobalServices(@Nonnull GlobalServices globalServices) {
      * @param globalServiceFactory the {@link GlobalServices.Factory}.
      */
     public void setGlobalServices(@Nonnull GlobalServices.Factory globalServiceFactory) {
-        if(didRunInitialStateChange) {
+        if(!canSetScopeProviders()) {
             throw new IllegalStateException("Scope provider should be set before the initial state change!");
         }
         if(globalServiceFactory == null) {
@@ -301,7 +312,6 @@ public void setGlobalServices(@Nonnull GlobalServices.Factory globalServiceFacto
         this.scopeManager.setGlobalServices(globalServiceFactory);
     }
 
-
     NavigationCore core;
 
     Map<Object, SavedState> keyStateMap = new HashMap<>();

simple-stack/src/test/java/com/zhuinden/simplestack/ScopingTest.java

@@ -162,6 +162,37 @@ public void handleStateChange(@Nonnull StateChange stateChange, @Nonnull Callbac
         }
     }
 
+    @Test
+    public void serviceProviderCanBeSetWorksCorrectly() {
+        Backstack backstack = new Backstack();
+
+        assertThat(backstack.canSetScopeProviders()).isTrue();
+        backstack.setup(History.of(testKey1));
+
+        assertThat(backstack.canSetScopeProviders()).isTrue();
+
+        backstack.setScopedServices(new ServiceProvider());
+        backstack.setGlobalServices(GlobalServices.builder().build());
+
+        assertThat(backstack.canSetScopeProviders()).isTrue();
+
+        backstack.setStateChanger(new StateChanger() {
+            @Override
+            public void handleStateChange(@Nonnull StateChange stateChange, @Nonnull Callback completionCallback) {
+                completionCallback.stateChangeComplete();
+            }
+        });
+
+        assertThat(backstack.canSetScopeProviders()).isFalse();
+
+        try {
+            backstack.setScopedServices(new ServiceProvider());
+            Assert.fail();
+        } catch(IllegalStateException e) {
+            // OK!
+        }
+    }
+
     @Test
     public void scopedServicesThrowIfNoScopedServicesAreDefinedAndServicesAreToBeBound() {
         Backstack backstack = new Backstack();