86 lines
3.1 KiB
Java
86 lines
3.1 KiB
Java
/*
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* Copyright (C) 2015 The Android Open Source Project
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* Copyright (C) 2024 The LineageOS Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.messaging.datamodel.binding;
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/*
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* The binding class keeps track of a binding between a ui component and an item of BindableData
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* It allows each side to ensure that when it communicates with the other they are still bound
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* together.
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* NOTE: Ensure that the UI component uses the same binding instance for it's whole lifetime
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* (DO NOT CREATE A NEW BINDING EACH TIME A NEW PIECE OF DATA IS BOUND)...
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*
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* The ui component owns the binding instance.
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* It can use it [isBound(data)] to see if the binding still binds to the right piece of data
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*
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* Upon binding the data is informed of a unique binding key generated in this class and can use
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* that to ensure that it is still issuing callbacks to the right piece of ui.
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*/
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public abstract class BindingBase<T extends BindableData> {
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/**
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* Creates a new exclusively owned binding for the owner object.
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*/
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public static <T extends BindableData> Binding<T> createBinding(final Object owner) {
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return new Binding<>(owner);
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}
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/**
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* Creates a new read-only binding referencing the source binding object.
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* TODO: We may want to refcount the Binding references, so that when the binding owner
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* calls unbind() when there's still outstanding references we can catch it.
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*/
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public static <T extends BindableData> ImmutableBindingRef<T> createBindingReference(
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final BindingBase<T> srcBinding) {
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return new ImmutableBindingRef<>(srcBinding);
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}
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/**
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* Creates a detachable binding for the owner object. Use this if your owner object is a UI
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* component that may undergo a "detached from window" -> "re-attached to window" transition.
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*/
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public static <T extends BindableData> DetachableBinding<T> createDetachableBinding(
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final Object owner) {
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return new DetachableBinding<>(owner);
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}
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public abstract T getData();
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/**
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* Check if binding connects to the specified data instance
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*/
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public abstract boolean isBound();
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/**
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* Check if binding connects to the specified data instance
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*/
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public abstract boolean isBound(final T data);
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/**
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* Throw if binding connects to the specified data instance
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*/
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public abstract void ensureBound();
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/**
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* Throw if binding connects to the specified data instance
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*/
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public abstract void ensureBound(final T data);
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/**
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* Return the binding id for this binding (will be null if not bound)
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*/
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public abstract String getBindingId();
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}
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