/**
 * Immutable model class for a Task.
 */
public final class Task {

    @NonNull
    private final String mId;

    @Nullable
    private final String mTitle;

    @Nullable
    private final String mDescription;

    private final boolean mCompleted;

@NonNull
    public String getId() {
        return mId;
    }

    @Nullable
    public String getTitle() {
        return mTitle;
    }

    @Nullable
    public String getTitleForList() {
        if (!Strings.isNullOrEmpty(mTitle)) {
            return mTitle;
        } else {
            return mDescription;
        }
    }

    @Nullable
    public String getDescription() {
        return mDescription;
    }

    public boolean isCompleted() {
        return mCompleted;
    }

    public boolean isActive() {
        return !mCompleted;
    }

    public boolean isEmpty() {
        return Strings.isNullOrEmpty(mTitle) &&
               Strings.isNullOrEmpty(mDescription);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Task task = (Task) o;
        return Objects.equal(mId, task.mId) &&
               Objects.equal(mTitle, task.mTitle) &&
               Objects.equal(mDescription, task.mDescription);
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(mId, mTitle, mDescription);
    }

    @Override
    public String toString() {
        return "Task with title " + mTitle;
    }

}

package com.example.android.architecture.blueprints.todoapp.taskdetail;

import com.example.android.architecture.blueprints.todoapp.BasePresenter;
import com.example.android.architecture.blueprints.todoapp.BaseView;

/**
 * This specifies the contract between the view and the presenter.
 */
public interface TaskDetailContract {

    interface View extends BaseView<Presenter> {

        void setLoadingIndicator(boolean active);

        void showMissingTask();

        void hideTitle();

        void showTitle(String title);

        void hideDescription();

        void showDescription(String description);

        void showCompletionStatus(boolean complete);

        void showEditTask(String taskId);

        void showTaskDeleted();

        void showTaskMarkedComplete();

        void showTaskMarkedActive();

        boolean isActive();
    }

    interface Presenter extends BasePresenter {

        void editTask();

        void deleteTask();

        void completeTask();

        void activateTask();
    }
}