多任務(wù)同時(shí)進(jìn)行

問(wèn)題：如果有一個(gè)對(duì)數(shù)據(jù)進(jìn)行權(quán)限檢查的操作，可能有1萬(wàn)條、10萬(wàn)條等等，只寫一個(gè)任務(wù)執(zhí)行它會(huì)花費(fèi)很多時(shí)間，這時(shí)可以考慮分成多個(gè)任務(wù)把數(shù)據(jù)分成多段同時(shí)進(jìn)行？

代碼如下：

public abstract class ParallelTask {
    private final static String TAG = "ParallelTask";

    public ParallelTask() {
    }


    public void preExecute(Object... args) {
    }

    public abstract void async1(); //必須實(shí)現(xiàn)

    public void async2() {
    }

    public void async3() {
    }

    public void async4() {
    }

    public void async5() {
    }

    public void async6() {
    }

    public void async7() {
    }

    public void async8() {
    }

    public void onAllExecute() {
    }

    public void onUICompleted() { //全部任務(wù)執(zhí)行完成后會(huì)執(zhí)行該方法
    }

    private Observable uiObs;

    /**
     * 執(zhí)行并行任務(wù)，結(jié)束后切換到UI線程
     */
    final public void execute(Object...args) {
        preExecute(args);
        //最外層，執(zhí)行UI線程
        uiObs = Observable.just(null).subscribeOn(AndroidSchedulers.mainThread());
        List<String> methods = getOverrideMethods();
        int size = methods.size();
        String[] ms = methods.toArray(new String[size]);
        getParallelObservable(ms)
                .observeOn(Schedulers.immediate())
                .subscribe(new Subscriber<String>() {
                    @Override
                    public void onCompleted() {
                        onAllExecute();
                        executeOnUICompleted();
                    }
                    @Override
                    public void onError(Throwable e) {
                        Log.e(TAG, "ParallelTask onError()", e);
                    }
                    @Override
                    public void onNext(String string) {
                    }
                });

    }

    /**
     * 最后切換到UI線程執(zhí)行
     */
    private void executeOnUICompleted(){
        if(uiObs != null){
            uiObs.subscribe(new Action1() {
                @Override
                public void call(Object o) {
                    onUICompleted();
                }
            });
        }
        uiObs = null;
    }

    private Observable<String> getParallelObservable(String[] methods) {
        return Observable.from(methods).flatMap(new Func1<String, Observable<String>>() {
            @Override
            public Observable<String> call(String s) {
                return Observable.just(s).subscribeOn(Schedulers.io()).map(new Func1<String, String>() {
                    @Override
                    public String call(String s) {
                        if ("async1".equals(s)) {
                            async1();
                        } else if ("async2".equals(s)) {
                            async2();
                        } else if ("async3".equals(s)) {
                            async3();
                        } else if ("async4".equals(s)) {
                            async4();
                        } else if ("async5".equals(s)) {
                            async5();
                        } else if ("async6".equals(s)) {
                            async6();
                        } else if ("async7".equals(s)) {
                            async7();
                        } else if ("async8".equals(s)) {
                            async8();
                        }
                        return s;
                    }
                });
            }
        });
    }

    /**
     * 獲取被重寫的方法
     * @return
     */
    private List<String> getOverrideMethods() {
        List<String> overrideMethods = new ArrayList<>();
        Method[] bfs = getClass().getDeclaredMethods();
        Method[] afs = ParallelTask.class.getDeclaredMethods();
        for (Method bm : bfs) {
            for (Method am : afs) {
                if (bm.getName().equals(am.getName()) &&
                        bm.getReturnType().equals(am.getReturnType())) {
                    Class[] bc = bm.getParameterTypes();
                    Class[] ac = am.getParameterTypes();
                    if (bc.length == ac.length) {
                        boolean isEqual = true;
                        for (int i = 0; i < bc.length; i++) {
                            if (!bc[i].equals(ac[i])) {
                                isEqual = false;
                                break;
                            }
                        }
                        if (isEqual) {
                            String name = bm.getName();
                            overrideMethods.add(name);
                        }
                    }
                }
            }
        }
        return overrideMethods;
    }

}

實(shí)現(xiàn)了ParallelTask抽象類，可以同時(shí)執(zhí)行8個(gè)任務(wù)，用戶可以自己增加個(gè)數(shù)。用戶可以創(chuàng)建一個(gè)ParallelTask類，然后實(shí)現(xiàn)async1方法，按照自己的需求實(shí)現(xiàn)其他方法即可。