Merge "Simple MVC based binding mechanism for android controls."

2 files changed, 217 insertions, 0 deletions

diff --git a/core/java/android/util/PropertyValueModel.java b/core/java/android/util/PropertyValueModel.java
new file mode 100755
index 000000000000..eb9c47d0c379
--- /dev/null
+++ b/core/java/android/util/PropertyValueModel.java
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.util;
+
+/**
+ * A value model for a {@link Property property} of a host object. This class can be used for
+ * both reflective and non-reflective property implementations.
+ *
+ * @param <H> the host type, where the host is the object that holds this property
+ * @param <T> the value type
+ *
+ * @see Property
+ * @see ValueModel
+ */
+public class PropertyValueModel<H, T> extends ValueModel<T> {
+    private final H mHost;
+    private final Property<H, T> mProperty;
+
+    private PropertyValueModel(H host, Property<H, T> property) {
+        mProperty = property;
+        mHost = host;
+    }
+
+    /**
+     * Returns the host.
+     *
+     * @return the host
+     */
+    public H getHost() {
+        return mHost;
+    }
+
+    /**
+     * Returns the property.
+     *
+     * @return the property
+     */
+    public Property<H, T> getProperty() {
+        return mProperty;
+    }
+
+    @Override
+    public Class<T> getType() {
+        return mProperty.getType();
+    }
+
+    @Override
+    public T get() {
+        return mProperty.get(mHost);
+    }
+
+    @Override
+    public void set(T value) {
+        mProperty.set(mHost, value);
+    }
+
+    /**
+     * Return an appropriate PropertyValueModel for this host and property.
+     *
+     * @param host the host
+     * @param property the property
+     * @return the value model
+     */
+    public static <H, T> PropertyValueModel<H, T> of(H host, Property<H, T> property) {
+        return new PropertyValueModel<H, T>(host, property);
+    }
+
+    /**
+     * Return a PropertyValueModel for this {@code host} and a
+     * reflective property, constructed from this {@code propertyType} and {@code propertyName}.
+     *
+     * @param host
+     * @param propertyType the property type
+     * @param propertyName the property name
+     * @return a value model with this host and a reflective property with this type and name
+     *
+     * @see Property#of
+     */
+    public static <H, T> PropertyValueModel<H, T> of(H host, Class<T> propertyType,
+            String propertyName) {
+        return of(host, Property.of((Class<H>) host.getClass(), propertyType, propertyName));
+    }
+
+    private static Class getNullaryMethodReturnType(Class c, String name) {
+        try {
+            return c.getMethod(name).getReturnType();
+        } catch (NoSuchMethodException e) {
+            return null;
+        }
+    }
+
+    private static Class getFieldType(Class c, String name) {
+        try {
+            return c.getField(name).getType();
+        } catch (NoSuchFieldException e) {
+            return null;
+        }
+    }
+
+    private static String capitalize(String name) {
+        if (name.isEmpty()) {
+            return name;
+        }
+        return Character.toUpperCase(name.charAt(0)) + name.substring(1);
+    }
+
+    /**
+     * Return a PropertyValueModel for this {@code host} and and {@code propertyName}.
+     *
+     * @param host the host
+     * @param propertyName the property name
+     * @return a value model with this host and a reflective property with this name
+     */
+    public static PropertyValueModel of(Object host, String propertyName) {
+        Class clazz = host.getClass();
+        String suffix = capitalize(propertyName);
+        Class propertyType = getNullaryMethodReturnType(clazz, "get" + suffix);
+        if (propertyType == null) {
+            propertyType = getNullaryMethodReturnType(clazz, "is" + suffix);
+        } 
+        if (propertyType == null) {
+            propertyType = getFieldType(clazz, propertyName); 
+        }         
+        if (propertyType == null) {
+            throw new NoSuchPropertyException(propertyName); 
+        }
+        return of(host, propertyType, propertyName);
+    }
+}
diff --git a/core/java/android/util/ValueModel.java b/core/java/android/util/ValueModel.java
new file mode 100755
index 000000000000..4789682ea496
--- /dev/null
+++ b/core/java/android/util/ValueModel.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.util;
+
+/**
+ * A ValueModel is an abstraction for a 'slot' or place in memory in which a value
+ * may be stored and retrieved. A common implementation of ValueModel is a regular property of
+ * an object, whose value may be retrieved by calling the appropriate <em>getter</em>
+ * method and set by calling the corresponding <em>setter</em> method.
+ *
+ * @param <T> the value type
+ *
+ * @see PropertyValueModel
+ */
+public abstract class ValueModel<T> {
+    /**
+     * The empty model should be used in place of {@code null} to indicate that a
+     * model has not been set. The empty model has no value and does nothing when it is set.
+     */
+    public static final ValueModel EMPTY = new ValueModel() {
+        @Override
+        public Class getType() {
+            return Object.class;
+        }
+
+        @Override
+        public Object get() {
+            return null;
+        }
+
+        @Override
+        public void set(Object value) {
+
+        }
+    };
+
+    protected ValueModel() {
+    }
+
+    /**
+     * Returns the type of this property.
+     *
+     * @return the property type
+     */
+    public abstract Class<T> getType();
+
+    /**
+     * Returns the value of this property.
+     *
+     * @return the property value
+     */
+    public abstract T get();
+
+    /**
+     * Sets the value of this property.
+     *
+     * @param value the new value for this property
+     */
+    public abstract void set(T value);
+}
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