LifeCycleComposer.java

/*
 * @license MIT/X11
 *
 * Copyright (c) 2016 Kozio Digital, Inc
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

public class LifecycleComposer {

    public final Observable<ActivityEvent> activityLifeCycle;
    public final Observable<FragmentEvent> fragmentLifeCycle;
    private final Observable<ViewModule.ViewEvent> viewLifeCycle;

    public LifecycleComposer(@NonNull Observable<ActivityEvent> activityEventObservable,
            @Nullable Observable<FragmentEvent> fragmentEventObservable) {
        this.activityLifeCycle = activityEventObservable;
        this.fragmentLifeCycle = fragmentEventObservable;
        viewLifeCycle = null;
    }

    public LifecycleComposer(@NonNull Observable<ActivityEvent> activityEventObservable,
            @NonNull Observable<ViewModule.ViewEvent> viewEventsObservable, Object... uselessArgs) {
        this.activityLifeCycle = activityEventObservable;
        this.fragmentLifeCycle = null;
        this.viewLifeCycle = viewEventsObservable;
    }

    public Observable<Boolean> onResumeStream() {
        if (fragmentLifeCycle != null) {
            return fragmentLifeCycle
                    .filter(e -> e.equals(FragmentEvent.RESUME))
                    .map(v -> true);
        } else if (viewLifeCycle != null) {
            return viewLifeCycle
                    .map(e -> e.equals(ViewModule.ViewEvent.ATTACHED));
        }
        return activityLifeCycle
                .filter(e -> e.equals(ActivityEvent.RESUME))
                .map(v -> true);
    }

    @NonNull
    @CheckResult
    private <TR> LifecycleTransformer<TR> bindToLifecycleActivity() {
        return RxLifecycleAndroid.bindActivity(activityLifeCycle);
    }

    @NonNull
    @CheckResult
    private <TR> LifecycleTransformer<TR> bindToLifecycleFragment() {
        return RxLifecycleAndroid.bindFragment(fragmentLifeCycle);
    }

    @NonNull
    @CheckResult
    public final <T> LifecycleTransformer<T> bindUntilEvent(@NonNull UniversalEvents event) {
        if (viewLifeCycle != null) {
            return RxLifecycle.bindUntilEvent(viewLifeCycle, event.convertToViewEvent());
        }
        if (fragmentLifeCycle == null) {
            return RxLifecycle.bindUntilEvent(activityLifeCycle, event.convertToActivityEvent());
        } else {
            return RxLifecycle.bindUntilEvent(fragmentLifeCycle, event.convertToFragmentEvent());
        }
    }

    public final <TR> ObservableTransformer<TR, TR> bindUntilEventMainThread(@NonNull final UniversalEvents event) {
        return bindUntilEventMainThread(event, false);
    }

    public final <TR> ObservableTransformer<TR, TR> bindUntilEventMainThread(@NonNull final UniversalEvents event,
            boolean delayError) {
        return new ObservableTransformer<TR, TR>() {
            @Override
            public ObservableSource<TR> apply(Observable<TR> upstream) {
                return (Observable<TR>) upstream.compose(bindUntilEvent(event))
                        .observeOn(AndroidSchedulers.mainThread(), delayError);
            }
        };
    }

    public final <TR> LifecycleTransformer<TR> bindToLifeCycle() {
        if (viewLifeCycle != null) {
            return RxLifecycle.bind(viewLifeCycle, viewEvent -> ViewModule.ViewEvent.DETACHED);
        }

        return fragmentLifeCycle == null ? this.<TR>bindToLifecycleActivity() : this.<TR>bindToLifecycleFragment();
    }

    public final <TR> ObservableTransformer<TR, TR> bindToLifeCycleMainThread() {
        return new ObservableTransformer<TR, TR>() {
            @Override
            public ObservableSource<TR> apply(Observable<TR> upstream) {
                return (Observable<TR>) upstream.compose(bindToLifeCycle()).observeOn(AndroidSchedulers.mainThread());
            }
        };
    }

    public enum UniversalEvents {
        RESUME,
        PAUSE,
        DESTROY_VIEW,
        DESTROY,
        START,
        STOP;

        ActivityEvent convertToActivityEvent() {
            switch (this) {
                case START:
                    return ActivityEvent.START;
                case RESUME:
                    return ActivityEvent.RESUME;
                case PAUSE:
                    return ActivityEvent.PAUSE;
                case STOP:
                    return ActivityEvent.STOP;
                case DESTROY_VIEW:
                    return ActivityEvent.DESTROY;
                default:
                case DESTROY:
                    return ActivityEvent.DESTROY;
            }
        }

        FragmentEvent convertToFragmentEvent() {
            switch (this) {
                case START:
                    return FragmentEvent.START;
                case RESUME:
                    return FragmentEvent.RESUME;
                case PAUSE:
                    return FragmentEvent.PAUSE;
                case STOP:
                    return FragmentEvent.STOP;
                case DESTROY_VIEW:
                    return FragmentEvent.DESTROY_VIEW;
                default:
                case DESTROY:
                    return FragmentEvent.DESTROY;
            }
        }

        public ViewModule.ViewEvent convertToViewEvent() {
            switch (this) {
                case START:
                    return ViewModule.ViewEvent.ATTACHED;
                case RESUME:
                    return ViewModule.ViewEvent.ATTACHED;
                case PAUSE:
                    return ViewModule.ViewEvent.DETACHED;
                case STOP:
                    return ViewModule.ViewEvent.DETACHED;
                case DESTROY_VIEW:
                    return ViewModule.ViewEvent.DETACHED;
                default:
                case DESTROY:
                    return ViewModule.ViewEvent.DETACHED;
            }
        }
    }

}