117 lines
3.6 KiB
Java
117 lines
3.6 KiB
Java
/*
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* Copyright (C) 2013 The Android Open Source 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 android.content;
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import android.compat.annotation.UnsupportedAppUsage;
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import android.os.Build;
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import android.os.Parcel;
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import android.os.Parcelable;
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/**
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* A single undoable operation. You must subclass this to implement the state
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* and behavior for your operation. Instances of this class are placed and
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* managed in an {@link UndoManager}.
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*
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* @hide
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*/
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public abstract class UndoOperation<DATA> implements Parcelable {
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UndoOwner mOwner;
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/**
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* Create a new instance of the operation.
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* @param owner Who owns the data being modified by this undo state; must be
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* returned by {@link UndoManager#getOwner(String, Object) UndoManager.getOwner}.
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*/
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@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
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public UndoOperation(UndoOwner owner) {
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mOwner = owner;
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}
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/**
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* Construct from a Parcel.
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*/
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@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
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protected UndoOperation(Parcel src, ClassLoader loader) {
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}
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/**
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* Owning object as given to {@link #UndoOperation(UndoOwner)}.
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*/
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public UndoOwner getOwner() {
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return mOwner;
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}
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/**
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* Synonym for {@link #getOwner()}.{@link android.content.UndoOwner#getData()}.
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*/
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public DATA getOwnerData() {
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return (DATA)mOwner.getData();
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}
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/**
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* Return true if this undo operation is a member of the given owner.
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* The default implementation is <code>owner == getOwner()</code>. You
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* can override this to provide more sophisticated dependencies between
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* owners.
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*/
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public boolean matchOwner(UndoOwner owner) {
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return owner == getOwner();
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}
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/**
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* Return true if this operation actually contains modification data. The
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* default implementation always returns true. If you return false, the
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* operation will be dropped when the final undo state is being built.
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*/
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public boolean hasData() {
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return true;
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}
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/**
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* Return true if this operation can be merged with a later operation.
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* The default implementation always returns true.
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*/
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public boolean allowMerge() {
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return true;
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}
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/**
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* Called when this undo state is being committed to the undo stack.
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* The implementation should perform the initial edits and save any state that
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* may be needed to undo them.
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*/
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public abstract void commit();
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/**
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* Called when this undo state is being popped off the undo stack (in to
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* the temporary redo stack). The implementation should remove the original
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* edits and thus restore the target object to its prior value.
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*/
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public abstract void undo();
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/**
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* Called when this undo state is being pushed back from the transient
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* redo stack to the main undo stack. The implementation should re-apply
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* the edits that were previously removed by {@link #undo}.
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*/
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public abstract void redo();
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public int describeContents() {
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return 0;
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}
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}
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