com.github.phantomthief.scope

Class Scope

java.lang.Object

com.github.phantomthief.scope.Scope

public final class Scope
extends Object

自定义Scope，支持如下功能：

• 开启一个自定义的Scope，在Scope范围内，可以通过 Scope 各个方法读写数据
• 可以通过 supplyWithExistScope(com.github.phantomthief.scope.Scope, com.github.phantomthief.util.ThrowableSupplier<T, X>) 或者 runWithExistScope(com.github.phantomthief.scope.Scope, com.github.phantomthief.util.ThrowableRunnable<X>) 绑定已经存在的scope

举个栗子：

 
 ScopeKey<String> TEST_KEY = allocate();

 runWithNewScope(() -> {
      TEST_KEY.set("abc");
      String result = TEST_KEY.get(); // get "abc"

      Scope scope = getCurrentScope();
      executor.execute(wrapRunnableExistScope(scope, () -> {
          String resultInScope = TEST_KEY.get(); // get "abc"
      });
 });
 

TODO: 当前实现是一种比较简易的方式，直接把所有Scope放到一个ThreadLocal里。 实际上这样在使用过程中会有二次hash查询的问题，对性能会有些许的影响，更好的做法是： 直接使用ThreadLocal（也就是使用内部的ThreadLocalMap），同时在Scope拷贝和清理时，维护一个额外的Set，进行ThreadLocal拷贝。 这样的优化考虑是：Scope正常访问的频率很高，而线程切换拷贝的概率比较低。 目前这个实现参考了 GRPC 的 Context API 以及 Spring 的 RequestContext， 相对比较简单，目前效率也可以接受。等到需要榨取性能时再对这个实现动手吧。

Author:

w.vela

Constructor Summary

Constructors

Constructor and Description
Scope()

Method Summary

Modifier and Type	Method and Description
static Scope	beginScope() 正常应该优先使用 supplyWithNewScope(com.github.phantomthief.util.ThrowableSupplier<T, X>) 或者 runWithNewScope(com.github.phantomthief.util.ThrowableRunnable<X>) 手工使用beginScope和endScope的场景只有在： 上面两个方法当需要抛出多个正交异常时会造成不必要的try/catch代码 开始scope和结束scope不在一个代码块中
static void	endScope()
static boolean	fastThreadLocalEnabled()
<T> T	get(ScopeKey<T> key)
static Scope	getCurrentScope()
static <X extends Throwable> void	runWithExistScope(Scope scope, com.github.phantomthief.util.ThrowableRunnable<X> runnable)
static <X extends Throwable> void	runWithNewScope(com.github.phantomthief.util.ThrowableRunnable<X> runnable)
<T> void	set(ScopeKey<T> key, T value)
static <T,X extends Throwable> T	supplyWithExistScope(Scope scope, com.github.phantomthief.util.ThrowableSupplier<T,X> supplier)
static <T,X extends Throwable> T	supplyWithNewScope(com.github.phantomthief.util.ThrowableSupplier<T,X> supplier)
static boolean	tryEnableFastThreadLocal()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Scope

public Scope()

Method Detail

fastThreadLocalEnabled

@Beta
public static boolean fastThreadLocalEnabled()

tryEnableFastThreadLocal

@Beta
public static boolean tryEnableFastThreadLocal()

Returns:

true if fast thread local was enabled.

runWithExistScope

public static <X extends Throwable> void runWithExistScope(@Nullable
                                                           Scope scope,
                                                           com.github.phantomthief.util.ThrowableRunnable<X> runnable)
                                                    throws X extends Throwable

Throws:

X extends Throwable

supplyWithExistScope

public static <T,X extends Throwable> T supplyWithExistScope(@Nullable
                                                             Scope scope,
                                                             com.github.phantomthief.util.ThrowableSupplier<T,X> supplier)
                                                      throws X extends Throwable

Throws:

X extends Throwable

runWithNewScope

public static <X extends Throwable> void runWithNewScope(@Nonnull
                                                         com.github.phantomthief.util.ThrowableRunnable<X> runnable)
                                                  throws X extends Throwable

Throws:

X extends Throwable

supplyWithNewScope

public static <T,X extends Throwable> T supplyWithNewScope(@Nonnull
                                                           com.github.phantomthief.util.ThrowableSupplier<T,X> supplier)
                                                    throws X extends Throwable

Throws:

X extends Throwable

beginScope

@Nonnull
public static Scope beginScope()

正常应该优先使用 supplyWithNewScope(com.github.phantomthief.util.ThrowableSupplier<T, X>) 或者 runWithNewScope(com.github.phantomthief.util.ThrowableRunnable<X>) 手工使用beginScope和endScope的场景只有在：

• 上面两个方法当需要抛出多个正交异常时会造成不必要的try/catch代码
• 开始scope和结束scope不在一个代码块中

Throws:

IllegalStateException - if try to start a new scope in an exist scope.

endScope

public static void endScope()

See Also:

beginScope()

getCurrentScope

@Nullable
public static Scope getCurrentScope()

set

public <T> void set(@Nonnull
                    ScopeKey<T> key,
                    T value)

get

public <T> T get(@Nonnull
                 ScopeKey<T> key)