堆棧內存溢出
  簡體   English   中英

引用內部靜態java類時工具箱編譯的奇怪行為

[英]Strange behavior of toolbox compilation when referencing an inner static java class

 原文  2013-04-15 11:54:47  9   1    java/ scala/ reflection/ scala-2.10/ toolbox

問題描述

假設我有以下java類： 

package com.test;
public class Outer {
    public static class Inner { public static final String VAL = "Inner"; }
}

我可以像您期望的那樣從scala代碼引用VAL常量，但是當我嘗試使用scala工具箱編譯器編譯引用該字段的代碼時，它會失敗。 （stacktrace遵循以下示例）。

這段代碼證明了我的意思： 

import scala.reflect.runtime.universe
import scala.tools.reflect.ToolBox
object Issue extends App {
  val mirror = universe.runtimeMirror(getClass.getClassLoader)
  val toolbox = ToolBox(mirror).mkToolBox()
  println                  (com.test.Outer.Inner.VAL) // prints 'Inner'
  val tree = toolbox.parse("com.test.Outer.Inner.VAL")
  val compiled = toolbox.compile(tree)() // fails to compile
}

這是我獲得的異常跟蹤： 

Exception in thread "main" scala.tools.reflect.ToolBoxError: reflective compilation has failed: 

value Inner is not a member of object com.test.Outer
    at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$ToolBoxGlobal.throwIfErrors(ToolBoxFactory.scala:319)
    at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$ToolBoxGlobal.compile(ToolBoxFactory.scala:252)
    at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl.compile(ToolBoxFactory.scala:416)
    at Issue$delayedInit$body.apply(Issue.scala:8)
    at scala.Function0$class.apply$mcV$sp(Function0.scala:40)
    at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
    at scala.App$$anonfun$main$1.apply(App.scala:71)
    at scala.App$$anonfun$main$1.apply(App.scala:71)
    at scala.collection.immutable.List.foreach(List.scala:318)
    at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:32)
    at scala.App$class.main(App.scala:71)
    at Issue$.main(Issue.scala:3)
    at Issue.main(Issue.scala)

有沒有人遇到過這個？ 有什么我可以改變（即編譯器選項）來使這項工作？

謝謝。

編輯

這是我用“-verbose -Yissue-debug”編譯時得到的： 

[reflect-compiler] made Scala package scala
[reflect-compiler] unpickling Scala package package and package scala, owner = package scala
[reflect-compiler] made Scala package java
[reflect-compiler] made Scala package lang
[reflect-compiler] made Scala package runtime
[reflect-compiler] made Scala package annotation
[reflect-compiler] unpickling Scala package package and package runtime, owner = package runtime
[reflect-compiler] made Scala package collection
[reflect-compiler] unpickling Scala package package and package collection, owner = package collection
[reflect-compiler] translating reflection info for Java class java.lang.Object
[reflect-compiler] unpickling Scala class Unit and object Unit, owner = package scala
[reflect-compiler] translating reflection info for Java class java.lang.Throwable
[reflect-compiler] unpickling Scala class Long and object Long, owner = package scala
[reflect-compiler] translating reflection info for Java class java.lang.InterruptedException
[reflect-compiler] unpickling Scala class Int and object Int, owner = package scala
[reflect-compiler] unpickling Scala class Boolean and object Boolean, owner = package scala
[reflect-compiler] translating reflection info for Java class java.lang.String
[reflect-compiler] translating reflection info for Java class java.lang.CloneNotSupportedException
[reflect-compiler] made Scala package io
[reflect-compiler] translating reflection info for Java interface java.io.Serializable
[reflect-compiler] translating reflection info for Java interface java.lang.CharSequence
[reflect-compiler] unpickling Scala class Char and object Char, owner = package scala
[reflect-compiler] translating reflection info for Java class java.io.ObjectStreamField
[reflect-compiler] made Scala package util
[reflect-compiler] unpickling Scala class Float and object Float, owner = package scala
[reflect-compiler] unpickling Scala class Double and object Double, owner = package scala
[reflect-compiler] unpickling Scala class Byte and object Byte, owner = package scala
[reflect-compiler] translating reflection info for Java class java.lang.StringBuffer
[reflect-compiler] translating reflection info for Java class java.util.Locale
[reflect-compiler] translating reflection info for Java class java.io.UnsupportedEncodingException
[reflect-compiler] made Scala package nio
[reflect-compiler] made Scala package charset
[reflect-compiler] translating reflection info for Java class java.nio.charset.Charset
[reflect-compiler] translating reflection info for Java class java.lang.StringBuilder
[reflect-compiler] translating reflection info for Java interface java.lang.Comparable
[reflect-compiler] made Scala package beans
parsing com.test.Outer.Inner.VAL
importing com.test.Outer.Inner.VAL
compiling com.test.Outer.Inner.VAL
[reflect-compiler] unpickling Scala class Predef and object Predef, owner = package scala
[reflect-compiler] unpickling Scala class ClassfileAnnotation and object ClassfileAnnotation, owner = package annotation
[reflect-compiler] unpickling Scala class Annotation and object Annotation, owner = package annotation
[reflect-compiler] unpickling Scala class StaticAnnotation and object StaticAnnotation, owner = package annotation
[reflect-compiler] made Scala package reflect
[reflect-compiler] unpickling Scala package package and package reflect, owner = package reflect
[reflect-compiler] made Scala package api
[reflect-compiler] unpickling Scala package package and package api, owner = package api
[reflect-compiler] unpickling Scala class Universe and object Universe, owner = package api
[reflect-compiler] unpickling Scala class Symbols and object Symbols, owner = package api
[reflect-compiler] unpickling Scala class Types and object Types, owner = package api
[reflect-compiler] unpickling Scala class FlagSets and object FlagSets, owner = package api
[reflect-compiler] unpickling Scala class Scopes and object Scopes, owner = package api
[reflect-compiler] unpickling Scala class Names and object Names, owner = package api
[reflect-compiler] unpickling Scala class Trees and object Trees, owner = package api
[reflect-compiler] unpickling Scala class Constants and object Constants, owner = package api
[reflect-compiler] unpickling Scala class Annotations and object Annotations, owner = package api
[reflect-compiler] unpickling Scala class Positions and object Positions, owner = package api
[reflect-compiler] unpickling Scala class Exprs and object Exprs, owner = package api
[reflect-compiler] unpickling Scala class TypeTags and object TypeTags, owner = package api
[reflect-compiler] unpickling Scala class TagInterop and object TagInterop, owner = package api
[reflect-compiler] unpickling Scala class StandardDefinitions and object StandardDefinitions, owner = package api
[reflect-compiler] unpickling Scala class StandardNames and object StandardNames, owner = package api
[reflect-compiler] unpickling Scala class BuildUtils and object BuildUtils, owner = package api
[reflect-compiler] unpickling Scala class Mirrors and object Mirrors, owner = package api
[reflect-compiler] unpickling Scala class Printers and object Printers, owner = package api
[reflect-compiler] unpickling Scala class Importers and object Importers, owner = package api
[reflect-compiler] made Scala package runtime
[reflect-compiler] unpickling Scala package package and package runtime, owner = package runtime
[reflect-compiler] unpickling Scala class StringContext and object StringContext, owner = package scala
[reflect-compiler] unpickling Scala class Product and object Product, owner = package scala
[reflect-compiler] unpickling Scala class Equals and object Equals, owner = package scala
[reflect-compiler] unpickling Scala class Serializable and object Serializable, owner = package scala
[reflect-compiler] made Scala package immutable
[reflect-compiler] unpickling Scala package package and package immutable, owner = package immutable
[reflect-compiler] unpickling Scala class Array and object Array, owner = package scala
[reflect-compiler] translating reflection info for Java interface java.lang.Cloneable
[reflect-compiler] unpickling Scala class AnyVal and object AnyVal, owner = package scala
[reflect-compiler] unpickling Scala class NotNull and object NotNull, owner = package scala
[reflect-compiler] unpickling Scala class LowPriorityImplicits and object LowPriorityImplicits, owner = package scala
[reflect-compiler] made Scala package com
[reflect-compiler] unpickling Scala class Dynamic and object Dynamic, owner = package scala
[reflect-compiler] made Scala package test
[reflect-compiler] translating reflection info for Java class com.test.Outer
[reflect-compiler] *** missing: Inner/true/object Outer/false/class scala.reflect.runtime.SynchronizedOps$$anon$1
java.lang.Exception
    at scala.tools.nsc.typechecker.Contexts$Context.issue(Contexts.scala:399)
    at scala.tools.nsc.typechecker.ContextErrors$ErrorUtils$.issueTypeError(ContextErrors.scala:84)
    at scala.tools.nsc.typechecker.ContextErrors$ErrorUtils$.issueNormalTypeError(ContextErrors.scala:69)
    at scala.tools.nsc.typechecker.ContextErrors$TyperContextErrors$TyperErrorGen$.NotAMemberError(ContextErrors.scala:331)
    at scala.tools.nsc.typechecker.Typers$Typer.handleMissing$1(Typers.scala:4846)
    at scala.tools.nsc.typechecker.Typers$Typer.scala$tools$nsc$typechecker$Typers$Typer$$typedSelect$1(Typers.scala:4851)
    at scala.tools.nsc.typechecker.Typers$Typer.typedSelectOrSuperCall$1(Typers.scala:4938)
    at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:5551)
    at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5630)
    at scala.tools.nsc.typechecker.Typers$Typer.typedQualifier(Typers.scala:5710)
    at scala.tools.nsc.typechecker.Typers$Typer.typedQualifier(Typers.scala:5716)
    at scala.tools.nsc.typechecker.Typers$Typer.typedSelectOrSuperCall$1(Typers.scala:4918)
    at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:5551)
    at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5630)
    at scala.tools.nsc.typechecker.Typers$Typer.transformedOrTyped(Typers.scala:5825)
    at scala.tools.nsc.typechecker.Typers$Typer.typedDefDef(Typers.scala:2250)
    at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:5557)
    at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5630)
    at scala.tools.nsc.typechecker.Typers$Typer.scala$tools$nsc$typechecker$Typers$Typer$$typedStat$1(Typers.scala:2921)
    at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$62.apply(Typers.scala:3025)
    at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$62.apply(Typers.scala:3025)
    at scala.collection.immutable.List.loop$1(List.scala:170)
    at scala.collection.immutable.List.mapConserve(List.scala:186)
    at scala.tools.nsc.typechecker.Typers$Typer.typedStats(Typers.scala:3025)
    at scala.tools.nsc.typechecker.Typers$Typer.typedTemplate(Typers.scala:1914)
    at scala.tools.nsc.typechecker.Typers$Typer.typedModuleDef(Typers.scala:1794)
    at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:5572)
    at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5630)
    at scala.tools.nsc.typechecker.Typers$Typer.scala$tools$nsc$typechecker$Typers$Typer$$typedStat$1(Typers.scala:2921)
    at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$62.apply(Typers.scala:3025)
    at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$62.apply(Typers.scala:3025)
    at scala.collection.immutable.List.loop$1(List.scala:170)
    at scala.collection.immutable.List.mapConserve(List.scala:186)
    at scala.tools.nsc.typechecker.Typers$Typer.typedStats(Typers.scala:3025)
    at scala.tools.nsc.typechecker.Typers$Typer.typedPackageDef$1(Typers.scala:5288)
    at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:5575)
    at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5630)
    at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5687)
    at scala.tools.nsc.typechecker.Analyzer$typerFactory$$anon$3.apply(Analyzer.scala:99)
    at scala.tools.nsc.Global$GlobalPhase.applyPhase(Global.scala:463)
    at scala.tools.nsc.typechecker.Analyzer$typerFactory$$anon$3$$anonfun$run$1.apply(Analyzer.scala:91)
    at scala.tools.nsc.typechecker.Analyzer$typerFactory$$anon$3$$anonfun$run$1.apply(Analyzer.scala:91)
    at scala.collection.Iterator$class.foreach(Iterator.scala:727)
    at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)
    at scala.tools.nsc.typechecker.Analyzer$typerFactory$$anon$3.run(Analyzer.scala:91)
    at scala.tools.nsc.Global$Run.compileUnitsInternal(Global.scala:1582)
    at scala.tools.nsc.Global$Run.compileUnits(Global.scala:1556)
    at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$ToolBoxGlobal.compile(ToolBoxFactory.scala:251)
    at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl.compile(ToolBoxFactory.scala:416)
    at Issue$delayedInit$body.apply(Issue.scala:8)
    at scala.Function0$class.apply$mcV$sp(Function0.scala:40)
    at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
    at scala.App$$anonfun$main$1.apply(App.scala:71)
    at scala.App$$anonfun$main$1.apply(App.scala:71)
    at scala.collection.immutable.List.foreach(List.scala:318)
    at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:32)
    at scala.App$class.main(App.scala:71)
    at Issue$.main(Issue.scala:3)
    at Issue.main(Issue.scala)
Exception in thread "main" scala.tools.reflect.ToolBoxError: reflective compilation has failed: 

[namer in 31ms]
[packageobjects in 0ms]
value Inner is not a member of object com.test.Outer
[typer in 211ms]
[total in 247ms]
[reset] recursing in package <root>
    at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$ToolBoxGlobal.throwIfErrors(ToolBoxFactory.scala:319)
    at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$ToolBoxGlobal.compile(ToolBoxFactory.scala:252)
    at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl.compile(ToolBoxFactory.scala:416)
    at Issue$delayedInit$body.apply(Issue.scala:8)
    at scala.Function0$class.apply$mcV$sp(Function0.scala:40)
    at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
    at scala.App$$anonfun$main$1.apply(App.scala:71)
    at scala.App$$anonfun$main$1.apply(App.scala:71)
    at scala.collection.immutable.List.foreach(List.scala:318)
    at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:32)
    at scala.App$class.main(App.scala:71)
    at Issue$.main(Issue.scala:3)
    at Issue.main(Issue.scala)

編輯2

我認為這是反射API中的一個錯誤，但我不確定。 我已經調試了打字階段，並提出了以下內容：

在為com.test.Outer分配了適當的符號后，我們到達了com.test.Outer.Inner的輸入階段。

在那里，它使用scala.reflect.internal.Scopes.Scope#lookupEntry(Name)查找Inner的符號。

檢查看在范圍表明，它含有ScopeEntry的ClassSymbol的Inner ，但范圍符號名和方法之間的平等的測試name參數是用做Object#equals （即equals沒有被重寫），並且這兩個名稱的實例不一樣。

關於符號名稱和傳遞的名稱參數的最后一個注釋是我看到它們具有相同的index字段。 我不確定這意味着什么，但我得到的印象是這意味着它們在名稱表中引用相同的名稱，所以它們是相等的（？）（兩者之間有一個區別，一個是TermName和符號的name是TypeName ）。

無論如何，我可能會打開一個錯誤Scala的bug追蹤器，只是想在這里總結一下。

1 個解決方案

解決方案1
 0  2013-09-12 18:55:08

正確 - 看起來Scala / JVM反射API無法確定VAR是嵌套Inner類的靜態成員。

暫無
暫無

聲明:本站的技術帖子網頁，遵循CC BY-SA 4.0協議，如果您需要轉載，請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.

相關問題 Java內部類編譯錯誤 在 static 方法中復制數組 Java 時的奇怪行為 Java中的內部靜態類 在內部類中使用泛型參數時Java編譯失敗 Java類CachedRowSetImpl的奇怪行為 java外部類將編譯效果內部類嗎 從 static 內部 Class 中引用非 static 變量 具有靜態屬性的Java代碼的奇怪行為 Java中的靜態內部類問題 Java內部類具有靜態方法
相關標簽
 
粵ICP備18138465號  © 2020-2024 STACKOOM.COM