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Diffstat (limited to 'src/com/android/messaging/datamodel/binding/BindingBase.java')
-rw-r--r-- | src/com/android/messaging/datamodel/binding/BindingBase.java | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/src/com/android/messaging/datamodel/binding/BindingBase.java b/src/com/android/messaging/datamodel/binding/BindingBase.java new file mode 100644 index 0000000..3d6da9b --- /dev/null +++ b/src/com/android/messaging/datamodel/binding/BindingBase.java @@ -0,0 +1,84 @@ +/* + * Copyright (C) 2015 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 com.android.messaging.datamodel.binding; + +/** + * The binding class keeps track of a binding between a ui component and an item of BindableData + * It allows each side to ensure that when it communicates with the other they are still bound + * together. + * NOTE: Ensure that the UI component uses the same binding instance for it's whole lifetime + * (DO NOT CREATE A NEW BINDING EACH TIME A NEW PIECE OF DATA IS BOUND)... + * + * The ui component owns the binding instance. + * It can use it [isBound(data)] to see if the binding still binds to the right piece of data + * + * Upon binding the data is informed of a unique binding key generated in this class and can use + * that to ensure that it is still issuing callbacks to the right piece of ui. + */ +public abstract class BindingBase<T extends BindableData> { + /** + * Creates a new exclusively owned binding for the owner object. + */ + public static <T extends BindableData> Binding<T> createBinding(final Object owner) { + return new Binding<T>(owner); + } + + /** + * Creates a new read-only binding referencing the source binding object. + * TODO: We may want to refcount the Binding references, so that when the binding owner + * calls unbind() when there's still outstanding references we can catch it. + */ + public static <T extends BindableData> ImmutableBindingRef<T> createBindingReference( + final BindingBase<T> srcBinding) { + return new ImmutableBindingRef<T>(srcBinding); + } + + /** + * Creates a detachable binding for the owner object. Use this if your owner object is a UI + * component that may undergo a "detached from window" -> "re-attached to window" transition. + */ + public static <T extends BindableData> DetachableBinding<T> createDetachableBinding( + final Object owner) { + return new DetachableBinding<T>(owner); + } + + public abstract T getData(); + + /** + * Check if binding connects to the specified data instance + */ + public abstract boolean isBound(); + + /** + * Check if binding connects to the specified data instance + */ + public abstract boolean isBound(final T data); + + /** + * Throw if binding connects to the specified data instance + */ + public abstract void ensureBound(); + + /** + * Throw if binding connects to the specified data instance + */ + public abstract void ensureBound(final T data); + + /** + * Return the binding id for this binding (will be null if not bound) + */ + public abstract String getBindingId(); +} |