izumin5210 · izumin5210 · Nov 23, 2015 · Nov 23, 2015 · Nov 23, 2015 · Nov 23, 2015
diff --git a/...cessor/src/main/java/info/izumin/android/droidux/processor/element/StoreClassElement.java b/...cessor/src/main/java/info/izumin/android/droidux/processor/element/StoreClassElement.java
@@ -1,5 +1,7 @@
 package info.izumin.android.droidux.processor.element;
 
+import android.databinding.Bindable;
+
 import com.squareup.javapoet.ClassName;
 import com.squareup.javapoet.CodeBlock;
 import com.squareup.javapoet.JavaFile;
@@ -11,7 +13,9 @@
 import javax.lang.model.element.Modifier;
 
 import info.izumin.android.droidux.Action;
+import info.izumin.android.droidux.History;
 import info.izumin.android.droidux.Store;
+import info.izumin.android.droidux.action.HistoryAction;
 import info.izumin.android.droidux.processor.model.DispatchableModel;
 import info.izumin.android.droidux.processor.model.ReducerModel;
 import info.izumin.android.droidux.processor.model.StoreModel;
@@ -26,6 +30,11 @@ public class StoreClassElement {
     public static final String TAG = StoreClassElement.class.getSimpleName();
 
     private static final String DISPATCH_TO_REDUCER_METHOD_NAME = "dispatchToReducer";
+    private static final String HISTORY_VARIABLE_NAME = "history";
+    private static final String HISTORY_SIZE_SETTER_METHOD_NAME = "setHistorySize";
+    private static final String STATE_GETTER_METHOD_NAME = "getState";
+    private static final String IS_UNDOABLE_METHOD_NAME = "isUndoable";
+    private static final String IS_REDOABLE_METHOD_NAME = "isRedoable";
 
     private final ReducerModel reducerModel;
     private final StoreModel storeModel;
@@ -41,27 +50,50 @@ public JavaFile createJavaFile() {
     }
 
     private TypeSpec createTypeSpec() {
-        return TypeSpec.classBuilder(storeModel.getClassName())
+        TypeSpec.Builder builder = TypeSpec.classBuilder(storeModel.getClassName())
                 .addModifiers(Modifier.PUBLIC, Modifier.FINAL)
                 .superclass(ParameterizedTypeName.get(ClassName.get(Store.class), storeModel.getState()))
-                .addField(reducerModel.getReducer(), reducerModel.getVariableName(), Modifier.PRIVATE, Modifier.FINAL)
-                .addMethod(createConstructor())
-                .addMethod(createMethodSpec())
-                .addType(new StoreBuilderClassElement(storeModel).createBuilderTypeSpec())
+                .addField(reducerModel.getReducer(), reducerModel.getVariableName(), Modifier.PRIVATE, Modifier.FINAL);
+
+        if (storeModel.isUndoable()) {
+            ParameterizedTypeName historyFieldName = ParameterizedTypeName.get(ClassName.get(History.class), storeModel.getState());
+            builder = builder.addField(historyFieldName, HISTORY_VARIABLE_NAME, Modifier.PRIVATE, Modifier.FINAL);
+        }
+
+        builder = builder.addMethod(createConstructor())
+                .addMethod(createMethodSpec());
+
+        if (storeModel.isUndoable()) {
+            builder = builder
+                    .addMethod(createUndoableStateGetterMethodSpec())
+                    .addMethod(createIsUndoableMethodSpec())
+                    .addMethod(createIsRedoableMethodSpec())
+                    .addMethod(createHistorySizeSetterMethodSpec());
+        }
+
+        return builder.addType(new StoreBuilderClassElement(storeModel).createBuilderTypeSpec())
                 .build();
     }
 
     private MethodSpec createConstructor() {
-        return MethodSpec.constructorBuilder()
+        MethodSpec.Builder builder = MethodSpec.constructorBuilder()
                 .addModifiers(Modifier.PROTECTED)
                 .addParameter(getParameterSpec(storeModel.getBuilder()))
                 .addStatement("super($N)", storeModel.getBuilderVariableName())
                 .addStatement("this.$N = $N.$N",
                         reducerModel.getVariableName(), storeModel.getBuilderVariableName(),
-                        reducerModel.getVariableName())
-                .addStatement("setState($N.$N)",
-                        storeModel.getBuilderVariableName(), storeModel.getStateVariableName())
-                .build();
+                        reducerModel.getVariableName());
+
+        if (storeModel.isUndoable()) {
+            builder = builder.addStatement("this.$N = new $T<>($N.$N)",
+                    HISTORY_VARIABLE_NAME, History.class,
+                    storeModel.getBuilderVariableName(), storeModel.getStateVariableName());
+        } else {
+            builder = builder.addStatement("setState($N.$N)",
+                    storeModel.getBuilderVariableName(), storeModel.getStateVariableName());
+        }
+
+        return builder.build();
     }
 
     private MethodSpec createMethodSpec() {
@@ -81,20 +113,71 @@ private CodeBlock createCodeBlock() {
 
         for (DispatchableModel dispatchableModel : reducerModel.getDispatchableModels()) {
             builder = builder.beginControlFlow("if (actionClass.isAssignableFrom($T.class))", dispatchableModel.getAction());
+
+            String stateGetter = storeModel.isUndoable() ? "getState().clone()" : "getState()";
+
             if (dispatchableModel.argumentCount() == 2) {
-                builder = builder.addStatement("result = $N.$N(getState(), ($T) action)",
+                builder = builder.addStatement("result = $N.$N(" + stateGetter + ", ($T) action)",
                         reducerModel.getVariableName(), dispatchableModel.getMethodName(), dispatchableModel.getAction());
             } else {
-                builder = builder.addStatement("result = $N.$N(getState())",
+                builder = builder.addStatement("result = $N.$N(" + stateGetter + ")",
                         reducerModel.getVariableName(), dispatchableModel.getMethodName());
             }
+            if (storeModel.isUndoable()) {
+                builder = builder.addStatement("$N.insert(result)", HISTORY_VARIABLE_NAME);
+            }
             builder = builder.endControlFlow();
         }
 
+        if (storeModel.isUndoable()) {
+            builder = builder.beginControlFlow("if ($T.class.isAssignableFrom(actionClass))", HistoryAction.class)
+                    .addStatement("$T historyAction = ($T) action", HistoryAction.class, HistoryAction.class)
+                    .beginControlFlow("if (historyAction.isAssignableTo(this))")
+                    .addStatement("result = historyAction.handle(history)")
+                    .endControlFlow()
+                    .endControlFlow();
+        }
+
         return builder
                 .beginControlFlow("if (result != null)")
                 .addStatement("setState(result)")
                 .endControlFlow()
                 .build();
     }
+
+    private MethodSpec createUndoableStateGetterMethodSpec() {
+        return MethodSpec.methodBuilder(STATE_GETTER_METHOD_NAME)
+                .addAnnotation(getOverrideAnnotation())
+                .addModifiers(Modifier.PUBLIC)
+                .returns(storeModel.getState())
+                .addStatement("return $N.getPresent()", HISTORY_VARIABLE_NAME)
+                .build();
+    }
+
+    private MethodSpec createIsUndoableMethodSpec() {
+        return MethodSpec.methodBuilder(IS_UNDOABLE_METHOD_NAME)
+                .addAnnotation(Bindable.class)
+                .addModifiers(Modifier.PUBLIC)
+                .returns(TypeName.BOOLEAN)
+                .addStatement("return $N.isUndoable()", HISTORY_VARIABLE_NAME)
+                .build();
+    }
+
+    private MethodSpec createIsRedoableMethodSpec() {
+        return MethodSpec.methodBuilder(IS_REDOABLE_METHOD_NAME)
+                .addAnnotation(Bindable.class)
+                .addModifiers(Modifier.PUBLIC)
+                .returns(TypeName.BOOLEAN)
+                .addStatement("return $N.isRedoable()", HISTORY_VARIABLE_NAME)
+                .build();
+    }
+
+    private MethodSpec createHistorySizeSetterMethodSpec() {
+        return MethodSpec.methodBuilder(HISTORY_SIZE_SETTER_METHOD_NAME)
+                .addModifiers(Modifier.PUBLIC)
+                .returns(TypeName.VOID)
+                .addParameter(TypeName.INT, "size")
+                .addStatement("$N.setLimit(size)", HISTORY_VARIABLE_NAME)
+                .build();
+    }
 }
diff --git a/...main/java/info/izumin/android/droidux/processor/exception/InvalidStateClassException.java b/...main/java/info/izumin/android/droidux/processor/exception/InvalidStateClassException.java
@@ -0,0 +1,10 @@
+package info.izumin.android.droidux.processor.exception;
+
+/**
+ * Created by izumin on 11/24/15.
+ */
+public class InvalidStateClassException extends RuntimeException {
+    public InvalidStateClassException(String message) {
+        super(message);
+    }
+}
diff --git a/...dux-processor/src/main/java/info/izumin/android/droidux/processor/model/ReducerModel.java b/...dux-processor/src/main/java/info/izumin/android/droidux/processor/model/ReducerModel.java
@@ -8,9 +8,12 @@
 import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.TypeElement;
 
+import info.izumin.android.droidux.UndoableState;
 import info.izumin.android.droidux.annotation.Dispatchable;
 import info.izumin.android.droidux.annotation.Reducer;
+import info.izumin.android.droidux.annotation.Undoable;
 import info.izumin.android.droidux.processor.exception.InvalidClassNameException;
+import info.izumin.android.droidux.processor.exception.InvalidStateClassException;
 import info.izumin.android.droidux.processor.util.StringUtils;
 
 import static info.izumin.android.droidux.processor.util.AnnotationUtils.findMethodsByAnnotation;
@@ -35,6 +38,8 @@ public class ReducerModel {
     private String stateName;
     private String stateVariableName;
 
+    private final boolean isUndoable;
+
     private StoreModel storeModel;
     private List<DispatchableModel> dispatchableModels;
 
@@ -46,6 +51,18 @@ public ReducerModel(TypeElement element) {
             this.stateVariableName = StringUtils.getLowerCamelFromUpperCamel(stateName);
         }
 
+        isUndoable = element.getAnnotation(Undoable.class) != null;
+
+        if (isUndoable) {
+            try {
+                if (!UndoableState.class.isAssignableFrom(Class.forName(state.packageName() + "." + state.simpleName()))) {
+                    throw new InvalidStateClassException("State class for undoable reducer must implement \"UndoableState<T>\".");
+                }
+            } catch (ClassNotFoundException e) {
+                e.printStackTrace();
+            }
+        }
+
         this.qualifiedName = element.getQualifiedName().toString();
         this.packageName = StringUtils.getPackageName(qualifiedName);
         this.className = StringUtils.getClassName(qualifiedName);
@@ -106,4 +123,8 @@ public StoreModel getStoreModel() {
     public List<DispatchableModel> getDispatchableModels() {
         return dispatchableModels;
     }
+
+    public boolean isUndoable() {
+        return isUndoable;
+    }
 }
diff --git a/droidux-processor/src/main/java/info/izumin/android/droidux/processor/model/StoreModel.java b/droidux-processor/src/main/java/info/izumin/android/droidux/processor/model/StoreModel.java
@@ -29,6 +29,8 @@ public class StoreModel {
     private final String builderName;
     private final String builderVariableName;
 
+    private final boolean isUndoable;
+
     private final ReducerModel reducerModel;
 
     public StoreModel(ReducerModel reducerModel) {
@@ -45,6 +47,7 @@ public StoreModel(ReducerModel reducerModel) {
         this.builderName = BUILDER_CLASS_NAME;
         this.builder = store.nestedClass(builderName);
         this.builderVariableName = getLowerCamelFromUpperCamel(builderName);
+        this.isUndoable = reducerModel.isUndoable();
     }
 
     public ClassName getState() {
@@ -94,4 +97,8 @@ public String getBuilderVariableName() {
     public ReducerModel getReducerModel() {
         return reducerModel;
     }
+
+    public boolean isUndoable() {
+        return isUndoable;
+    }
 }
diff --git a/...x-processor/src/test/java/info/izumin/android/droidux/processor/DroiduxProcessorTest.java b/...x-processor/src/test/java/info/izumin/android/droidux/processor/DroiduxProcessorTest.java
@@ -62,6 +62,14 @@ public void combinedTwoReducers() {
         );
     }
 
+    @Test
+    public void undoableReducer() {
+        assertJavaSource(
+                forSourceLines("UndoableTodoListReducer", Source.UndoableTodoList.TARGET),
+                forSourceLines("DroiduxUndoableTodoListStore", Source.UndoableTodoList.GENERATED)
+        );
+    }
+
     @Test
     public void dispatchableMethodTakesWrongStateType() {
         expectedException.expect(RuntimeException.class);
@@ -111,4 +119,14 @@ public void reducerWithoutSuffix() {
                 forSourceLines("DroiduxTodoListReduce", Source.EMPTY)
         );
     }
+
+    @Test
+    public void undoableReducerWithoutUndoableState() {
+        expectedException.expect(RuntimeException.class);
+        expectedException.expectMessage("State class for undoable reducer must implement \"UndoableState<T>\".");
+        assertJavaSource(
+                forSourceLines("CounterReduce", Source.UndoableReducerWithoutUndoableState.TARGET),
+                forSourceLines("DroiduxTodoListReduce", Source.EMPTY)
+        );
+    }
 }