com.sun.tools.javac.jvm
Class ClassReader

java.lang.Object
  com.sun.tools.javac.jvm.ClassFile
      com.sun.tools.javac.jvm.ClassReader

All Implemented Interfaces:

Symbol.Completer

Direct Known Subclasses:

JavadocClassReader

public class ClassReader
extends ClassFile
implements Symbol.Completer

This class provides operations to read a classfile into an internal representation. The internal representation is anchored in a ClassSymbol which contains in its scope symbol representations for all other definitions in the classfile. Top-level Classes themselves appear as members of the scopes of PackageSymbols.

This is NOT part of any API supported by Sun Microsystems. If you write code that depends on this, you do so at your own risk. This code and its internal interfaces are subject to change or deletion without notice.

Nested Class Summary

(package private) class	ClassReader.AnnotationCompleter
(package private) class	ClassReader.AnnotationDefaultCompleter
(package private) class	ClassReader.AnnotationDeproxy
(package private) static class	ClassReader.ArrayAttributeProxy
class	ClassReader.BadClassFile Error Diagnoses
(package private) static class	ClassReader.CompoundAnnotationProxy A temporary proxy representing a compound attribute.
(package private) static class	ClassReader.EnumAttributeProxy
(package private) static interface	ClassReader.ProxyVisitor
static interface	ClassReader.SourceCompleter
private static class	ClassReader.SourceFileObject A subclass of JavaFileObject for the sourcefile attribute found in a classfile.

Nested classes/interfaces inherited from class com.sun.tools.javac.jvm.ClassFile

ClassFile.NameAndType

Field Summary

(package private) boolean	allowAnnotations Switch: allow annotations.
(package private) boolean	allowGenerics Switch: read GJ signature information.
(package private) boolean	allowVarargs Switch: read varargs attribute.
(package private) Annotate	annotate
(package private) int	bp The current input pointer.
(package private) byte[]	buf The buffer containing the currently read class file.
private boolean	cacheCompletionFailure Switch: cache completion failures unless -XDdev is used
private Symbol.CompletionFailure	cachedCompletionFailure
(package private) boolean	checkClassFile Switch: check class file for correct minor version, unrecognized attributes.
private java.util.Map<Name,Symbol.ClassSymbol>	classes A hashtable containing the encountered top-level and member classes, indexed by flat names.
protected static Context.Key<ClassReader>	classReaderKey The context key for the class reader.
(package private) Name	completionFailureName Force a completion failure on this name
protected JavaFileObject	currentClassFile The path name of the class file currently being read.
protected JavaFileManager.Location	currentLoc
protected Symbol	currentOwner The class or method currently being read.
(package private) JCDiagnostic.Factory	diagFactory Factory for diagnostics
private JavaFileManager	fileManager Access to files
private boolean	filling We can only read a single class file at a time; this flag keeps track of when we are currently reading a class file.
private List<Type>	foundTypeVariables
(package private) Log	log The log to use for verbose output
private List<Type>	missingTypeVariables
(package private) Names	names The name table.
private java.util.Map<Name,Symbol.PackageSymbol>	packages A hashtable containing the encountered packages.
(package private) int[]	poolIdx For every constant pool entry, an index into buf where the defining section of the entry is found.
(package private) java.lang.Object[]	poolObj The objects of the constant pool.
boolean	preferSource Switch: prefer source files instead of newer when both source and class are available
boolean	readAllOfClassFile Switch: read constant pool and code sections.
private boolean	readingClassAttr
boolean	saveParameterNames Switch: preserve parameter names from the variable table.
(package private) int	sbp
(package private) boolean	sigEnterPhase
(package private) int	siglimit
(package private) byte[]	signature The unread portion of the currently read type is signature[sigp..siglimit-1].
(package private) byte[]	signatureBuffer
(package private) int	sigp
ClassReader.SourceCompleter	sourceCompleter Can be reassigned from outside: the completer to be used for ".java" files.
private boolean	suppressFlush
(package private) Symtab	syms The symbol table.
(package private) Types	types
protected Scope	typevars The current scope where type variables are entered.
(package private) boolean	verbose Switch: verbose output.
private boolean	verbosePath

Fields inherited from class com.sun.tools.javac.jvm.ClassFile

CONSTANT_Class, CONSTANT_Double, CONSTANT_Fieldref, CONSTANT_Float, CONSTANT_Integer, CONSTANT_InterfaceMethodref, CONSTANT_Long, CONSTANT_Methodref, CONSTANT_NameandType, CONSTANT_String, CONSTANT_Unicode, CONSTANT_Utf8, JAVA_MAGIC, MAX_CODE, MAX_DIMENSIONS, MAX_LOCALS, MAX_PARAMETERS, MAX_STACK

Constructor Summary

protected

ClassReader(Context context, boolean definitive) Construct a new class reader, optionally treated as the definitive classreader for this invocation.

Method Summary

(package private) long	adjustClassFlags(long flags)
(package private) long	adjustFieldFlags(long flags) Adjusting flags
(package private) long	adjustMethodFlags(long flags)
(package private) void	attachAnnotationDefault(Symbol sym) Attach the default value for an annotation element.
(package private) void	attachAnnotations(Symbol sym) Attach annotations.
(package private) void	attachParameterAnnotations(Symbol method) Attach parameter annotations.
ClassReader.BadClassFile	badClassFile(java.lang.String key, java.lang.Object... args)
(package private) Type	classSigToType() Convert class signature to type, where signature is implicit.
void	complete(Symbol sym) Completion for classes to be loaded.
private void	completeEnclosing(Symbol.ClassSymbol c) Tries to complete lexically enclosing classes if c looks like a nested class.
private void	completeOwners(Symbol o) complete up through the enclosing package.
private JCDiagnostic	createBadClassFileDiagnostic(JavaFileObject file, JCDiagnostic diag)
Symbol.ClassSymbol	defineClass(Name name, Symbol owner) Define a new class given its name and owner.
private static byte[]	ensureCapacity(byte[] buf, int needed)
Symbol.ClassSymbol	enterClass(Name flatname) Create a new member or toplevel class symbol with given flat name and enter in `classes' unless already there.
Symbol.ClassSymbol	enterClass(Name flatName, JavaFileObject classFile) Creates a new toplevel class symbol with given flat name and given class (or source) file.
Symbol.ClassSymbol	enterClass(Name name, Symbol.TypeSymbol owner) Create a new toplevel or member class symbol with given name and owner and enter in `classes' unless already there.
private void	enterMember(Symbol.ClassSymbol c, Symbol sym) Add member to class unless it is synthetic.
Symbol.PackageSymbol	enterPackage(Name fullname) Make a package, given its fully qualified name.
Symbol.PackageSymbol	enterPackage(Name name, Symbol.PackageSymbol owner) Make a package, given its unqualified name and enclosing package.
protected void	enterTypevars(Symbol sym)
protected void	enterTypevars(Type t) Enter type variables of this classtype and all enclosing ones in `typevars'.
protected void	extraFileActions(Symbol.PackageSymbol pack, JavaFileObject fe) this is used to support javadoc
private void	fillIn(Symbol.ClassSymbol c) Fill in definition of class `c' from corresponding class or source file.
private void	fillIn(Symbol.PackageSymbol p) Load directory of package into members scope.
private void	fillIn(Symbol.PackageSymbol p, JavaFileManager.Location location, java.lang.Iterable<JavaFileObject> files)
private Symbol.MethodSymbol	findMethod(ClassFile.NameAndType nt, Scope scope, long flags)
(package private) Type	findTypeVar(Name name) Find type variable with given name in `typevars' scope.
(package private) char	getChar(int bp) Extract a character at position bp from buf.
(package private) double	getDouble(int bp) Extract a double at position bp from buf.
(package private) float	getFloat(int bp) Extract a float at position bp from buf.
(package private) int	getInt(int bp) Extract an integer at position bp from buf.
(package private) long	getLong(int bp) Extract a long integer at position bp from buf.
protected java.util.EnumSet<JavaFileObject.Kind>	getPackageFileKinds() specifies types of files to be read when filling in a package symbol
protected void	includeClassFile(Symbol.PackageSymbol p, JavaFileObject file) Include class corresponding to given class file in package, unless (1) we already have one the same kind (.class or .java), or (2) we have one of the other kind, and the given class file is older.
(package private) void	indexPool() Index all constant pool entries, writing their start addresses into poolIdx.
void	init(Symtab syms) Initialize classes and packages, treating this as the definitive classreader.
private void	init(Symtab syms, boolean definitive) Initialize classes and packages, optionally treating this as the definitive classreader.
static ClassReader	instance(Context context) Get the ClassReader instance for this invocation.
private static boolean	isAsciiDigit(char c) Character.isDigit answers true to some non-ascii digits.
private boolean	isSameBinaryType(Type.MethodType mt1, Type.MethodType mt2) Similar to Types.isSameType but avoids completion
Symbol.ClassSymbol	loadClass(Name flatname) Load a toplevel class with given fully qualified name The class is entered into `classes' only if load was successful.
private Symbol.CompletionFailure	newCompletionFailure(Symbol.TypeSymbol c, JCDiagnostic diag) Static factory for CompletionFailure objects.
(package private) char	nextChar() Read a character.
(package private) int	nextInt() Read an integer.
boolean	packageExists(Name fullname) Check to see if a package exists, given its fully qualified name.
protected JavaFileObject	preferredFileObject(JavaFileObject a, JavaFileObject b) Implement policy to choose to derive information from a source file or a class file when both are present.
private void	printCCF(java.lang.String key, java.lang.Object arg) Output for "-checkclassfile" option.
private void	printVerbose(java.lang.String key, java.lang.CharSequence arg) Output for "-verbose" option.
(package private) Attribute	readAttributeValue()
(package private) void	readClass(Symbol.ClassSymbol c) Read contents of a given class symbol `c'.
(package private) void	readClassAttr(Symbol.ClassSymbol c, Name attrName, int attrLen) Read class attribute.
(package private) void	readClassAttrs(Symbol.ClassSymbol c) Read class attributes.
private void	readClassFile(Symbol.ClassSymbol c) Read a class file.
(package private) java.lang.Object	readClassOrType(int i) If name is an array type or class signature, return the corresponding type; otherwise return a ClassSymbol with given name.
(package private) Symbol.ClassSymbol	readClassSymbol(int i) Read class entry.
(package private) Code	readCode(Symbol owner) Read code block.
(package private) ClassReader.CompoundAnnotationProxy	readCompoundAnnotation()
(package private) void	readEnclosingMethodAttr(Symbol sym)
(package private) Type	readEnumType(int i)
(package private) Symbol.VarSymbol	readField() Read a field.
(package private) void	readInnerClasses(Symbol.ClassSymbol c) Read inner class info.
private static byte[]	readInputStream(byte[] buf, java.io.InputStream s)
(package private) void	readMemberAttr(Symbol sym, Name attrName, int attrLen) Read member attribute.
(package private) void	readMemberAttrs(Symbol sym) Read member attributes.
(package private) Symbol.MethodSymbol	readMethod() Read a method.
(package private) Name	readName(int i) Read name.
(package private) java.lang.Object	readPool(int i) Read constant pool entry at start address i, use pool as a cache.
(package private) Type	readType(int i) Read signature and convert to type.
(package private) Type	readTypeOrClassSymbol(int i)
(package private) List<Type>	readTypeParams(int i) Read signature and convert to type parameters.
(package private) Type	sigToType() Convert signature to type, where signature is implicit.
(package private) Type	sigToType(byte[] sig, int offset, int len) Convert signature to type, where signature is a byte array segment.
(package private) Type	sigToTypeParam() Convert (implicit) signature to type parameter.
(package private) List<Type>	sigToTypeParams() Convert signature to type parameters, where signature is implicit.
(package private) List<Type>	sigToTypeParams(byte[] sig, int offset, int len) Convert signature to type parameters, where signature is a byte array segment.
(package private) List<Type>	sigToTypes(char terminator) Convert (implicit) signature to list of types until `terminator' is encountered.
private Name	simpleBinaryName(Name self, Name enclosing)
(package private) void	skipMember() Skip a field or method
(package private) void	unrecognized(Name attrName) Report unrecognized attribute.

Methods inherited from class com.sun.tools.javac.jvm.ClassFile

externalize, externalize, internalize, internalize

Methods inherited from class java.lang.Object

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

Field Detail

classReaderKey

protected static final Context.Key<ClassReader> classReaderKey

The context key for the class reader.

annotate

Annotate annotate

verbose

boolean verbose

Switch: verbose output.

checkClassFile

boolean checkClassFile

Switch: check class file for correct minor version, unrecognized attributes.

readAllOfClassFile

public boolean readAllOfClassFile

Switch: read constant pool and code sections. This switch is initially set to false but can be turned on from outside.

allowGenerics

boolean allowGenerics

Switch: read GJ signature information.

allowVarargs

boolean allowVarargs

Switch: read varargs attribute.

allowAnnotations

boolean allowAnnotations

Switch: allow annotations.

saveParameterNames

public boolean saveParameterNames

Switch: preserve parameter names from the variable table.

cacheCompletionFailure

private boolean cacheCompletionFailure

Switch: cache completion failures unless -XDdev is used

preferSource

public boolean preferSource

Switch: prefer source files instead of newer when both source and class are available

log

final Log log

The log to use for verbose output

syms

Symtab syms

The symbol table.

types

Types types

names

final Names names

The name table.

completionFailureName

final Name completionFailureName

Force a completion failure on this name

fileManager

private final JavaFileManager fileManager

Access to files

diagFactory

JCDiagnostic.Factory diagFactory

Factory for diagnostics

sourceCompleter

public ClassReader.SourceCompleter sourceCompleter

Can be reassigned from outside: the completer to be used for ".java" files. If this remains unassigned ".java" files will not be loaded.

classes

private java.util.Map<Name,Symbol.ClassSymbol> classes

A hashtable containing the encountered top-level and member classes, indexed by flat names. The table does not contain local classes.

packages

private java.util.Map<Name,Symbol.PackageSymbol> packages

A hashtable containing the encountered packages.

typevars

protected Scope typevars

The current scope where type variables are entered.

currentClassFile

protected JavaFileObject currentClassFile

The path name of the class file currently being read.

currentOwner

protected Symbol currentOwner

The class or method currently being read.

buf

byte[] buf

The buffer containing the currently read class file.

bp

int bp

The current input pointer.

poolObj

java.lang.Object[] poolObj

The objects of the constant pool.

poolIdx

int[] poolIdx

For every constant pool entry, an index into buf where the defining section of the entry is found.

signature

byte[] signature

The unread portion of the currently read type is signature[sigp..siglimit-1].

sigp

int sigp

siglimit

int siglimit

sigEnterPhase

boolean sigEnterPhase

signatureBuffer

byte[] signatureBuffer

sbp

int sbp

readingClassAttr

private boolean readingClassAttr

missingTypeVariables

private List<Type> missingTypeVariables

foundTypeVariables

private List<Type> foundTypeVariables

suppressFlush

private boolean suppressFlush

filling

private boolean filling

We can only read a single class file at a time; this flag keeps track of when we are currently reading a class file.

cachedCompletionFailure

private Symbol.CompletionFailure cachedCompletionFailure

currentLoc

protected JavaFileManager.Location currentLoc

verbosePath

private boolean verbosePath

Constructor Detail

ClassReader

protected ClassReader(Context context,
                      boolean definitive)

Construct a new class reader, optionally treated as the definitive classreader for this invocation.

Method Detail

instance

public static ClassReader instance(Context context)

Get the ClassReader instance for this invocation.

init

public void init(Symtab syms)

Initialize classes and packages, treating this as the definitive classreader.

init

private void init(Symtab syms,
                  boolean definitive)

Initialize classes and packages, optionally treating this as the definitive classreader.

enterMember

private void enterMember(Symbol.ClassSymbol c,
                         Symbol sym)

Add member to class unless it is synthetic.

createBadClassFileDiagnostic

private JCDiagnostic createBadClassFileDiagnostic(JavaFileObject file,
                                                  JCDiagnostic diag)

badClassFile

public ClassReader.BadClassFile badClassFile(java.lang.String key,
                                             java.lang.Object... args)

nextChar

char nextChar()

Read a character.

nextInt

int nextInt()

Read an integer.

getChar

char getChar(int bp)

Extract a character at position bp from buf.

getInt

int getInt(int bp)

Extract an integer at position bp from buf.

getLong

long getLong(int bp)

Extract a long integer at position bp from buf.

getFloat

float getFloat(int bp)

Extract a float at position bp from buf.

getDouble

double getDouble(int bp)

Extract a double at position bp from buf.

indexPool

void indexPool()

Index all constant pool entries, writing their start addresses into poolIdx.

readPool

java.lang.Object readPool(int i)

Read constant pool entry at start address i, use pool as a cache.

readType

Type readType(int i)

Read signature and convert to type.

readClassOrType

java.lang.Object readClassOrType(int i)

If name is an array type or class signature, return the corresponding type; otherwise return a ClassSymbol with given name.

readTypeParams

List<Type> readTypeParams(int i)

Read signature and convert to type parameters.

readClassSymbol

Symbol.ClassSymbol readClassSymbol(int i)

Read class entry.

readName

Name readName(int i)

Read name.

sigToType

Type sigToType(byte[] sig,
               int offset,
               int len)

Convert signature to type, where signature is a byte array segment.

sigToType

Type sigToType()

Convert signature to type, where signature is implicit.

classSigToType

Type classSigToType()

Convert class signature to type, where signature is implicit.

sigToTypes

List<Type> sigToTypes(char terminator)

Convert (implicit) signature to list of types until `terminator' is encountered.

sigToTypeParams

List<Type> sigToTypeParams(byte[] sig,
                           int offset,
                           int len)

Convert signature to type parameters, where signature is a byte array segment.

sigToTypeParams

List<Type> sigToTypeParams()

Convert signature to type parameters, where signature is implicit.

sigToTypeParam

Type sigToTypeParam()

Convert (implicit) signature to type parameter.

findTypeVar

Type findTypeVar(Name name)

Find type variable with given name in `typevars' scope.

unrecognized

void unrecognized(Name attrName)

Report unrecognized attribute.

readMemberAttr

void readMemberAttr(Symbol sym,
                    Name attrName,
                    int attrLen)

Read member attribute.

readEnclosingMethodAttr

void readEnclosingMethodAttr(Symbol sym)

simpleBinaryName

private Name simpleBinaryName(Name self,
                              Name enclosing)

findMethod

private Symbol.MethodSymbol findMethod(ClassFile.NameAndType nt,
                                       Scope scope,
                                       long flags)

isSameBinaryType

private boolean isSameBinaryType(Type.MethodType mt1,
                                 Type.MethodType mt2)

Similar to Types.isSameType but avoids completion

isAsciiDigit

private static boolean isAsciiDigit(char c)

Character.isDigit answers true to some non-ascii digits. This one does not. copied from java.lang.Class

readMemberAttrs

void readMemberAttrs(Symbol sym)

Read member attributes.

readClassAttr

void readClassAttr(Symbol.ClassSymbol c,
                   Name attrName,
                   int attrLen)

Read class attribute.

readClassAttrs

void readClassAttrs(Symbol.ClassSymbol c)

Read class attributes.

readCode

Code readCode(Symbol owner)

Read code block.

attachAnnotations

void attachAnnotations(Symbol sym)

Attach annotations.

attachParameterAnnotations

void attachParameterAnnotations(Symbol method)

Attach parameter annotations.

attachAnnotationDefault

void attachAnnotationDefault(Symbol sym)

Attach the default value for an annotation element.

readTypeOrClassSymbol

Type readTypeOrClassSymbol(int i)

readEnumType

Type readEnumType(int i)

readCompoundAnnotation

ClassReader.CompoundAnnotationProxy readCompoundAnnotation()

readAttributeValue

Attribute readAttributeValue()

readField

Symbol.VarSymbol readField()

Read a field.

readMethod

Symbol.MethodSymbol readMethod()

Read a method.

skipMember

void skipMember()

Skip a field or method

enterTypevars

protected void enterTypevars(Type t)

Enter type variables of this classtype and all enclosing ones in `typevars'.

enterTypevars

protected void enterTypevars(Symbol sym)

readClass

void readClass(Symbol.ClassSymbol c)

Read contents of a given class symbol `c'. Both external and internal versions of an inner class are read.

readInnerClasses

void readInnerClasses(Symbol.ClassSymbol c)

Read inner class info. For each inner/outer pair allocate a member class.

readClassFile

private void readClassFile(Symbol.ClassSymbol c)
                    throws java.io.IOException

Read a class file.

Throws:

java.io.IOException

adjustFieldFlags

long adjustFieldFlags(long flags)

Adjusting flags

adjustMethodFlags

long adjustMethodFlags(long flags)

adjustClassFlags

long adjustClassFlags(long flags)

defineClass

public Symbol.ClassSymbol defineClass(Name name,
                                      Symbol owner)

Define a new class given its name and owner.

enterClass

public Symbol.ClassSymbol enterClass(Name name,
                                     Symbol.TypeSymbol owner)

Create a new toplevel or member class symbol with given name and owner and enter in `classes' unless already there.

enterClass

public Symbol.ClassSymbol enterClass(Name flatName,
                                     JavaFileObject classFile)

Creates a new toplevel class symbol with given flat name and given class (or source) file.

Parameters:

flatName - a fully qualified binary class name

classFile - the class file or compilation unit defining the class (may be null)

Returns:

a newly created class symbol

Throws:

java.lang.AssertionError - if the class symbol already exists

enterClass

public Symbol.ClassSymbol enterClass(Name flatname)

Create a new member or toplevel class symbol with given flat name and enter in `classes' unless already there.

complete

public void complete(Symbol sym)
              throws Symbol.CompletionFailure

Completion for classes to be loaded. Before a class is loaded we make sure its enclosing class (if any) is loaded.

Specified by:

complete in interface Symbol.Completer

Throws:

Symbol.CompletionFailure

completeOwners

private void completeOwners(Symbol o)

complete up through the enclosing package.

completeEnclosing

private void completeEnclosing(Symbol.ClassSymbol c)

Tries to complete lexically enclosing classes if c looks like a nested class. This is similar to completeOwners but handles the situation when a nested class is accessed directly as it is possible with the Tree API or javax.lang.model.*.

fillIn

private void fillIn(Symbol.ClassSymbol c)

Fill in definition of class `c' from corresponding class or source file.

readInputStream

private static byte[] readInputStream(byte[] buf,
                                      java.io.InputStream s)
                               throws java.io.IOException

Throws:

java.io.IOException

ensureCapacity

private static byte[] ensureCapacity(byte[] buf,
                                     int needed)

newCompletionFailure

private Symbol.CompletionFailure newCompletionFailure(Symbol.TypeSymbol c,
                                                      JCDiagnostic diag)

Static factory for CompletionFailure objects. In practice, only one can be used at a time, so we share one to reduce the expense of allocating new exception objects.

loadClass

public Symbol.ClassSymbol loadClass(Name flatname)
                             throws Symbol.CompletionFailure

Load a toplevel class with given fully qualified name The class is entered into `classes' only if load was successful.

Throws:

Symbol.CompletionFailure

packageExists

public boolean packageExists(Name fullname)

Check to see if a package exists, given its fully qualified name.

enterPackage

public Symbol.PackageSymbol enterPackage(Name fullname)

Make a package, given its fully qualified name.

enterPackage

public Symbol.PackageSymbol enterPackage(Name name,
                                         Symbol.PackageSymbol owner)

Make a package, given its unqualified name and enclosing package.

includeClassFile

protected void includeClassFile(Symbol.PackageSymbol p,
                                JavaFileObject file)

Include class corresponding to given class file in package, unless (1) we already have one the same kind (.class or .java), or (2) we have one of the other kind, and the given class file is older.

preferredFileObject

protected JavaFileObject preferredFileObject(JavaFileObject a,
                                             JavaFileObject b)

Implement policy to choose to derive information from a source file or a class file when both are present. May be overridden by subclasses.

getPackageFileKinds

protected java.util.EnumSet<JavaFileObject.Kind> getPackageFileKinds()

specifies types of files to be read when filling in a package symbol

extraFileActions

protected void extraFileActions(Symbol.PackageSymbol pack,
                                JavaFileObject fe)

this is used to support javadoc

fillIn

private void fillIn(Symbol.PackageSymbol p)
             throws java.io.IOException

Load directory of package into members scope.

Throws:

java.io.IOException

fillIn

private void fillIn(Symbol.PackageSymbol p,
                    JavaFileManager.Location location,
                    java.lang.Iterable<JavaFileObject> files)

printVerbose

private void printVerbose(java.lang.String key,
                          java.lang.CharSequence arg)

Output for "-verbose" option.

Parameters:

key - The key to look up the correct internationalized string.

arg - An argument for substitution into the output string.

printCCF

private void printCCF(java.lang.String key,
                      java.lang.Object arg)

Output for "-checkclassfile" option.

Parameters:

key - The key to look up the correct internationalized string.

arg - An argument for substitution into the output string.