Handle a generic Serializable or Parcelable properly, see #24

Author: vRallev

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## 1.1.1
 
 * Add a Proguard rule to keep the class name if the class contains a `State` or `StateReflection annoation`, see #23
+* Handle a generic `Serializable` or `Parcelable` properly, see #24
 
 ## 1.1.0 (2017-06-05)
 

demo/src/main/java/com/evernote/android/test/data/GenericSerializable.java

@@ -0,0 +1,19 @@
+package com.evernote.android.test.data;
+
+import java.io.Serializable;
+
+/**
+ * @author rwondratschek
+ */
+public class GenericSerializable<T> implements Serializable {
+
+    private T mValue;
+
+    public T getValue() {
+        return mValue;
+    }
+
+    public void setValue(T value) {
+        mValue = value;
+    }
+}

demo/src/main/java/com/evernote/android/test/data/TestJavaGenericSerializable.java

@@ -0,0 +1,20 @@
+package com.evernote.android.test.data;
+
+import com.evernote.android.state.State;
+
+/**
+ * @author rwondratschek
+ */
+public class TestJavaGenericSerializable {
+
+    @State
+    private GenericSerializable<String> mGenericSerializable;
+
+    public GenericSerializable<String> getGenericSerializable() {
+        return mGenericSerializable;
+    }
+
+    public void setGenericSerializable(GenericSerializable<String> genericSerializable) {
+        mGenericSerializable = genericSerializable;
+    }
+}

demo/src/main/kotlin/com/evernote/android/state/test/TestKotlinGenericSerializable.kt

@@ -0,0 +1,13 @@
+package com.evernote.android.state.test
+
+import com.evernote.android.state.State
+import com.evernote.android.test.data.GenericSerializable
+
+/**
+ * @author rwondratschek
+ */
+class TestKotlinGenericSerializable {
+
+    @State
+    var genericSerializable: GenericSerializable<String>? = null
+}

demo/src/test/kotlin/com/evernote/android/state/test/TestKotlinBundling.kt

@@ -12,6 +12,8 @@ package com.evernote.android.state.test
 
 import android.os.Bundle
 import com.evernote.android.state.StateSaver
+import com.evernote.android.test.data.GenericSerializable
+import com.evernote.android.test.data.TestJavaGenericSerializable
 import org.assertj.core.api.Assertions.assertThat
 import org.junit.FixMethodOrder
 import org.junit.Test
@@ -121,4 +123,37 @@ class TestKotlinBundling {
         assertThat(kotlinBoolean.test1).isTrue()
         assertThat(kotlinBoolean.isTest2).isTrue()
     }
+
+    @Test
+    fun testGenericSerializable() {
+        val javaGenericSerializable = TestJavaGenericSerializable()
+        val kotlinGenericSerializable = TestKotlinGenericSerializable()
+        assertThat(javaGenericSerializable.genericSerializable).isNull()
+        assertThat(kotlinGenericSerializable.genericSerializable).isNull()
+
+        val bundle = Bundle()
+        StateSaver.saveInstanceState(javaGenericSerializable, bundle)
+        StateSaver.saveInstanceState(kotlinGenericSerializable, bundle)
+
+        javaGenericSerializable.genericSerializable = GenericSerializable()
+        kotlinGenericSerializable.genericSerializable = GenericSerializable()
+
+        StateSaver.restoreInstanceState(javaGenericSerializable, bundle)
+        StateSaver.restoreInstanceState(kotlinGenericSerializable, bundle)
+        assertThat(javaGenericSerializable.genericSerializable).isNull()
+        assertThat(kotlinGenericSerializable.genericSerializable).isNull()
+
+        javaGenericSerializable.genericSerializable = GenericSerializable()
+        kotlinGenericSerializable.genericSerializable = GenericSerializable()
+        StateSaver.saveInstanceState(javaGenericSerializable, bundle)
+        StateSaver.saveInstanceState(kotlinGenericSerializable, bundle)
+
+        javaGenericSerializable.genericSerializable = null
+        kotlinGenericSerializable.genericSerializable = null
+
+        StateSaver.restoreInstanceState(javaGenericSerializable, bundle)
+        StateSaver.restoreInstanceState(kotlinGenericSerializable, bundle)
+        assertThat(javaGenericSerializable.genericSerializable as Any).isNotNull()
+        assertThat(kotlinGenericSerializable.genericSerializable as Any).isNotNull()
+    }
 }

processor/src/main/java/com/evernote/android/state/StateProcessor.java

@@ -121,6 +121,11 @@ public int compare(Element o1, Element o2) {
     private static final String PARCELABLE_CLASS_NAME = Parcelable.class.getName();
     private static final String SERIALIZABLE_CLASS_NAME = Serializable.class.getName();
 
+    private static final Set<String> GENERIC_SUPER_TYPES = Collections.unmodifiableSet(new HashSet<String>() {{
+        add(PARCELABLE_CLASS_NAME);
+        add(SERIALIZABLE_CLASS_NAME);
+    }});
+
     private static final Set<String> IGNORED_TYPE_DECLARATIONS = Collections.unmodifiableSet(new HashSet<String>() {{
         add(Bundle.class.getName());
         add(String.class.getName());
@@ -785,15 +790,23 @@ private TypeMirror getInsertedType(Element field, @SuppressWarnings("SameParamet
     }
 
     private TypeMirror getInsertedType(TypeMirror fieldType, boolean checkIgnoredTypes) {
+        TypeElement classElement = mElementUtils.getTypeElement(eraseGenericIfNecessary(fieldType).toString());
+        List<? extends TypeMirror> superTypes = classElement == null ? null : mTypeUtils.directSupertypes(classElement.asType());
+
         if (fieldType instanceof DeclaredType) {
-            // generic type, return the generic value
             List<? extends TypeMirror> typeArguments = ((DeclaredType) fieldType).getTypeArguments();
             if (typeArguments != null && !typeArguments.isEmpty()) {
+                // generic type, return the generic value
+
+                if (superTypes != null && isSuperType(superTypes, GENERIC_SUPER_TYPES) && !fieldType.toString().startsWith(ArrayList.class.getName())) {
+                    // if this is generic Parcelable or Serializable, then use the type, ignore ArrayList, which also implements Serializable
+                    return fieldType;
+                }
+
                 return getInsertedType(typeArguments.get(0), false);
             }
         }
 
-        TypeElement classElement = mElementUtils.getTypeElement(fieldType.toString());
         if (classElement == null || OBJECT_CLASS_NAME.equals(classElement.toString())) {
             return null;
         }
@@ -802,19 +815,13 @@ private TypeMirror getInsertedType(TypeMirror fieldType, boolean checkIgnoredTyp
             return null;
         }
 
-        List<? extends TypeMirror> typeMirrors = mTypeUtils.directSupertypes(classElement.asType());
-        if (typeMirrors != null) {
-            for (TypeMirror superType : typeMirrors) {
-                String superTypeString = superType.toString();
-                if (PARCELABLE_CLASS_NAME.equals(superTypeString)) {
-                    return fieldType;
-                }
-                if (SERIALIZABLE_CLASS_NAME.equals(superTypeString)) {
-                    return fieldType;
-                }
+        if (superTypes != null) {
+            if (isSuperType(superTypes, GENERIC_SUPER_TYPES)) {
+                // either instance of Serializable or Parcelable
+                return fieldType;
             }
 
-            for (TypeMirror superType : typeMirrors) {
+            for (TypeMirror superType : superTypes) {
                 TypeMirror result = getInsertedType(eraseGenericIfNecessary(superType), checkIgnoredTypes);
                 if (result != null) {
                     // always return the passed in type and not any super type
@@ -825,6 +832,15 @@ private TypeMirror getInsertedType(TypeMirror fieldType, boolean checkIgnoredTyp
         return null;
     }
 
+    private boolean isSuperType(List<? extends TypeMirror> typeMirrors, Collection<String> superTypes) {
+        for (TypeMirror superType : typeMirrors) {
+            if (superTypes.contains(superType.toString())) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     private String getLicenseHeader() throws IOException {
         if (mLicenseHeader == null) {
             synchronized (this) {