RxJava 和 RxAndroid 一 (基础)

package lib.com.myapplication;

import android.support.annotation.NonNull;

import android.util.Log;

import java.util.ArrayList;

import java.util.Collection;

import java.util.List;

import java.util.concurrent.ConcurrentHashMap;

import rx.Observable;

import rx.subjects.PublishSubject;

import rx.subjects.Subject;

/**

 * Created by ${zyj} on 2016/5/6.

 */

public class RxBus {

    private static final String TAG = RxBus.class.getSimpleName();

    private static RxBus instance;

    public static boolean DEBUG = false;

    public static RxBus get() {

        if (instance == null) {

            synchronized (RxBus.class) {

                if (instance == null) {

                    instance = new RxBus();

                }

            }

        }

        return instance;

    }

    private RxBus() {

    }

    private ConcurrentHashMap<Object, List<Subject>> subjectMapper = new ConcurrentHashMap<>();

    @SuppressWarnings("unchecked")

    public <T> Observable<T> register(@NonNull Object tag, @NonNull Class<T> clazz) {

        List<Subject> subjectList = subjectMapper.get(tag);

        if (null == subjectList) {

            subjectList = new ArrayList<>();

            subjectMapper.put(tag, subjectList);

        }

        Subject<T, T> subject;

        subjectList.add(subject = PublishSubject.create());

        if (DEBUG) Log.d(TAG, "[register]subjectMapper: " + subjectMapper);

        return subject;

    }

    public void unregister(@NonNull Object tag, @NonNull Observable observable) {

        List<Subject> subjects = subjectMapper.get(tag);

        if (null != subjects) {

            if ( observable != null  && subjects.contains( observable )){

                subjects.remove((Subject) observable);

            }

            if (isEmpty(subjects)) {

                subjectMapper.remove(tag);

            }

        }

        if (DEBUG) Log.d(TAG, "[unregister]subjectMapper: " + subjectMapper);

    }

    public void post(@NonNull Object content) {

        post( content.getClass().getName(), content);

    }

    @SuppressWarnings("unchecked")

    public void post(@NonNull Object tag, @NonNull Object content) {

        List<Subject> subjectList = subjectMapper.get(tag);

        if (!isEmpty(subjectList)) {

            for (Subject subject : subjectList) {

                subject.onNext(content);

            }

        }

        if (DEBUG) Log.d(TAG, "[send]subjectMapper: " + subjectMapper);

    }

    private boolean isEmpty(Collection collection) {

        return null == collection || collection.isEmpty();

    }

}