1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5 * in compliance with the License. You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software distributed under the License
10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11 * or implied. See the License for the specific language governing permissions and limitations under
12 * the License.
13 */
14package androidx.leanback.widget;
15
16import java.util.ArrayList;
17import java.util.HashMap;
18
19/**
20 * A ClassPresenterSelector selects a {@link Presenter} based on the item's
21 * Java class.
22 */
23public final class ClassPresenterSelector extends PresenterSelector {
24
25    private final ArrayList<Presenter> mPresenters = new ArrayList<Presenter>();
26
27    private final HashMap<Class<?>, Object> mClassMap = new HashMap<Class<?>, Object>();
28
29    /**
30     * Sets a presenter to be used for the given class.
31     * @param cls The data model class to be rendered.
32     * @param presenter The presenter that renders the objects of the given class.
33     * @return This ClassPresenterSelector object.
34     */
35    public ClassPresenterSelector addClassPresenter(Class<?> cls, Presenter presenter) {
36        mClassMap.put(cls, presenter);
37        if (!mPresenters.contains(presenter)) {
38            mPresenters.add(presenter);
39        }
40        return this;
41    }
42
43    /**
44     * Sets a presenter selector to be used for the given class.
45     * @param cls The data model class to be rendered.
46     * @param presenterSelector The presenter selector that finds the right presenter for a given
47     *                          class.
48     * @return This ClassPresenterSelector object.
49     */
50    public ClassPresenterSelector addClassPresenterSelector(Class<?> cls,
51            PresenterSelector presenterSelector) {
52        mClassMap.put(cls, presenterSelector);
53        Presenter[] innerPresenters = presenterSelector.getPresenters();
54        for (int i = 0; i < innerPresenters.length; i++)
55        if (!mPresenters.contains(innerPresenters[i])) {
56            mPresenters.add(innerPresenters[i]);
57        }
58        return this;
59    }
60
61    @Override
62    public Presenter getPresenter(Object item) {
63        Class<?> cls = item.getClass();
64        Object presenter = null;
65
66        do {
67            presenter = mClassMap.get(cls);
68            if (presenter instanceof PresenterSelector) {
69                Presenter innerPresenter = ((PresenterSelector) presenter).getPresenter(item);
70                if (innerPresenter != null) {
71                    return innerPresenter;
72                }
73            }
74            cls = cls.getSuperclass();
75        } while (presenter == null && cls != null);
76
77        return (Presenter) presenter;
78    }
79
80    @Override
81    public Presenter[] getPresenters() {
82        return mPresenters.toArray(new Presenter[mPresenters.size()]);
83    }
84}
85