org.eclipse.jdt.core
Class Signature

java.lang.Object
  |
  +--org.eclipse.jdt.core.Signature

public final class Signature

extends Object

Provides methods for encoding and decoding type and method signature strings.

The syntax for a type signature is:

 typeSignature ::=
     "B"  // byte
   | "C"  // char
   | "D"  // double
   | "F"  // float
   | "I"  // int
   | "J"  // long
   | "S"  // short
   | "V"  // void
   | "Z"  // boolean
   | "L" + binaryTypeName + ";"  // resolved named type (i.e., in compiled code)
   | "Q" + sourceTypeName + ";"  // unresolved named type (i.e., in source code)
   | "[" + typeSignature  // array of type denoted by typeSignature
 

Examples:

• "[[I" denotes int[][]
• "Ljava.lang.String;" denotes java.lang.String in compiled code
• "QString" denotes String in source code
• "Qjava.lang.String" denotes java.lang.String in source code
• "[QString" denotes String[] in source code

The syntax for a method signature is:

 methodSignature ::= "(" + paramTypeSignature* + ")" + returnTypeSignature
 paramTypeSignature ::= typeSignature
 returnTypeSignature ::= typeSignature
 

Examples:

• "()I" denotes int foo()
• "([Ljava.lang.String;)V" denotes void foo(java.lang.String[]) in compiled code
• "(QString;)QObject;" denotes Object foo(String) in source code

This class provides static methods and constants only; it is not intended to be instantiated or subclassed by clients.

Field Summary

static char	C_ARRAY Character constant indicating an array type in a signature.
static char	C_BOOLEAN Character constant indicating the primitive type boolean in a signature.
static char	C_BYTE Character constant indicating the primitive type byte in a signature.
static char	C_CHAR Character constant indicating the primitive type char in a signature.
static char	C_DOLLAR Character constant indicating the dollar in a signature.
static char	C_DOT Character constant indicating the dot in a signature.
static char	C_DOUBLE Character constant indicating the primitive type double in a signature.
static char	C_FLOAT Character constant indicating the primitive type float in a signature.
static char	C_INT Character constant indicating the primitive type int in a signature.
static char	C_LONG Character constant indicating the primitive type long in a signature.
static char	C_NAME_END Character constant indicating the end of a named type in a signature.
static char	C_PARAM_END Character constant indicating the end of a parameter type list in a signature.
static char	C_PARAM_START Character constant indicating the start of a parameter type list in a signature.
static char	C_RESOLVED Character constant indicating the start of a resolved, named type in a signature.
static char	C_SEMICOLON Character constant indicating the semicolon in a signature.
static char	C_SHORT Character constant indicating the primitive type short in a signature.
static char	C_UNRESOLVED Character constant indicating the start of an unresolved, named type in a signature.
static char	C_VOID Character constant indicating result type void in a signature.
static String	SIG_BOOLEAN String constant for the signature of the primitive type boolean.
static String	SIG_BYTE String constant for the signature of the primitive type byte.
static String	SIG_CHAR String constant for the signature of the primitive type char.
static String	SIG_DOUBLE String constant for the signature of the primitive type double.
static String	SIG_FLOAT String constant for the signature of the primitive type float.
static String	SIG_INT String constant for the signature of the primitive type int.
static String	SIG_LONG String constant for the signature of the primitive type long.
static String	SIG_SHORT String constant for the signature of the primitive type short.
static String	SIG_VOID String constant for the signature of result type void.

Method Summary

static char[]	createArraySignature(char[] typeSignature, int arrayCount) Creates a new type signature with the given amount of array nesting added to the given type signature.
static String	createArraySignature(String typeSignature, int arrayCount) Creates a new type signature with the given amount of array nesting added to the given type signature.
static char[]	createCharArrayTypeSignature(char[] typeName, boolean isResolved) Creates a new type signature from the given type name encoded as a character array.
static char[]	createMethodSignature(char[][] parameterTypes, char[] returnType) Creates a method signature from the given parameter and return type signatures.
static String	createMethodSignature(String[] parameterTypes, String returnType) Creates a method signature from the given parameter and return type signatures.
static String	createTypeSignature(char[] typeName, boolean isResolved) Creates a new type signature from the given type name encoded as a character array.
static String	createTypeSignature(String typeName, boolean isResolved) Creates a new type signature from the given type name.
static int	getArrayCount(char[] typeSignature) Returns the array count (array nesting depth) of the given type signature.
static int	getArrayCount(String typeSignature) Returns the array count (array nesting depth) of the given type signature.
static char[]	getElementType(char[] typeSignature) Returns the type signature without any array nesting.
static String	getElementType(String typeSignature) Returns the type signature without any array nesting.
static int	getParameterCount(char[] methodSignature) Returns the number of parameter types in the given method signature.
static int	getParameterCount(String methodSignature) Returns the number of parameter types in the given method signature.
static char[][]	getParameterTypes(char[] methodSignature) Extracts the parameter type signatures from the given method signature.
static String[]	getParameterTypes(String methodSignature) Extracts the parameter type signatures from the given method signature.
static char[]	getQualifier(char[] name) Returns a char array containing all but the last segment of the given dot-separated qualified name.
static String	getQualifier(String name) Returns a string containing all but the last segment of the given dot-separated qualified name.
static char[]	getReturnType(char[] methodSignature) Extracts the return type from the given method signature.
static String	getReturnType(String methodSignature) Extracts the return type from the given method signature.
static char[]	getSimpleName(char[] name) Returns the last segment of the given dot-separated qualified name.
static String	getSimpleName(String name) Returns the last segment of the given dot-separated qualified name.
static char[][]	getSimpleNames(char[] name) Returns all segments of the given dot-separated qualified name.
static String[]	getSimpleNames(String name) Returns all segments of the given dot-separated qualified name.
static char[]	toCharArray(char[] signature) Converts the given type signature to a readable string.
static char[]	toCharArray(char[] methodSignature, char[] methodName, char[][] parameterNames, boolean fullyQualifyTypeNames, boolean includeReturnType) Converts the given method signature to a readable form.
static char[]	toQualifiedName(char[][] segments) Converts the given array of qualified name segments to a qualified name.
static String	toQualifiedName(String[] segments) Converts the given array of qualified name segments to a qualified name.
static String	toString(String signature) Converts the given type signature to a readable string.
static String	toString(String methodSignature, String methodName, String[] parameterNames, boolean fullyQualifyTypeNames, boolean includeReturnType) Converts the given method signature to a readable string.

Methods inherited from class java.lang.Object

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

Field Detail

C_BOOLEAN

public static final char C_BOOLEAN

Character constant indicating the primitive type boolean in a signature. Value is 'Z'.

See Also:

Constant Field Values

C_BYTE

public static final char C_BYTE

Character constant indicating the primitive type byte in a signature. Value is 'B'.

See Also:

Constant Field Values

C_CHAR

public static final char C_CHAR

Character constant indicating the primitive type char in a signature. Value is 'C'.

See Also:

Constant Field Values

C_DOUBLE

public static final char C_DOUBLE

Character constant indicating the primitive type double in a signature. Value is 'D'.

See Also:

Constant Field Values

C_FLOAT

public static final char C_FLOAT

Character constant indicating the primitive type float in a signature. Value is 'F'.

See Also:

Constant Field Values

C_INT

public static final char C_INT

Character constant indicating the primitive type int in a signature. Value is 'I'.

See Also:

Constant Field Values

C_SEMICOLON

public static final char C_SEMICOLON

Character constant indicating the semicolon in a signature. Value is ';'.

See Also:

Constant Field Values

C_LONG

public static final char C_LONG

Character constant indicating the primitive type long in a signature. Value is 'J'.

See Also:

Constant Field Values

C_SHORT

public static final char C_SHORT

Character constant indicating the primitive type short in a signature. Value is 'S'.

See Also:

Constant Field Values

C_VOID

public static final char C_VOID

Character constant indicating result type void in a signature. Value is 'V'.

See Also:

Constant Field Values

C_DOT

public static final char C_DOT

Character constant indicating the dot in a signature. Value is '.'.

See Also:

Constant Field Values

C_DOLLAR

public static final char C_DOLLAR

Character constant indicating the dollar in a signature. Value is '$'.

See Also:

Constant Field Values

C_ARRAY

public static final char C_ARRAY

Character constant indicating an array type in a signature. Value is '['.

See Also:

Constant Field Values

C_RESOLVED

public static final char C_RESOLVED

Character constant indicating the start of a resolved, named type in a signature. Value is 'L'.

See Also:

Constant Field Values

C_UNRESOLVED

public static final char C_UNRESOLVED

Character constant indicating the start of an unresolved, named type in a signature. Value is 'Q'.

See Also:

Constant Field Values

C_NAME_END

public static final char C_NAME_END

Character constant indicating the end of a named type in a signature. Value is ';'.

See Also:

Constant Field Values

C_PARAM_START

public static final char C_PARAM_START

Character constant indicating the start of a parameter type list in a signature. Value is '('.

See Also:

Constant Field Values

C_PARAM_END

public static final char C_PARAM_END

Character constant indicating the end of a parameter type list in a signature. Value is ')'.

See Also:

Constant Field Values

SIG_BOOLEAN

public static final String SIG_BOOLEAN

String constant for the signature of the primitive type boolean. Value is "Z".

See Also:

Constant Field Values

SIG_BYTE

public static final String SIG_BYTE

String constant for the signature of the primitive type byte. Value is "B".

See Also:

Constant Field Values

SIG_CHAR

public static final String SIG_CHAR

String constant for the signature of the primitive type char. Value is "C".

See Also:

Constant Field Values

SIG_DOUBLE

public static final String SIG_DOUBLE

String constant for the signature of the primitive type double. Value is "D".

See Also:

Constant Field Values

SIG_FLOAT

public static final String SIG_FLOAT

String constant for the signature of the primitive type float. Value is "F".

See Also:

Constant Field Values

SIG_INT

public static final String SIG_INT

String constant for the signature of the primitive type int. Value is "I".

See Also:

Constant Field Values

SIG_LONG

public static final String SIG_LONG

String constant for the signature of the primitive type long. Value is "J".

See Also:

Constant Field Values

SIG_SHORT

public static final String SIG_SHORT

String constant for the signature of the primitive type short. Value is "S".

See Also:

Constant Field Values

SIG_VOID

public static final String SIG_VOID

String constant for the signature of result type void. Value is "V".

See Also:

Constant Field Values

Method Detail

createArraySignature

public static char[] createArraySignature(char[] typeSignature,
                                          int arrayCount)

Creates a new type signature with the given amount of array nesting added to the given type signature.

Parameters:

typeSignature - the type signature

arrayCount - the desired number of levels of array nesting

Returns:

the encoded array type signature

Since:

2.0

createArraySignature

public static String createArraySignature(String typeSignature,
                                          int arrayCount)

Creates a new type signature with the given amount of array nesting added to the given type signature.

Parameters:

typeSignature - the type signature

arrayCount - the desired number of levels of array nesting

Returns:

the encoded array type signature

createMethodSignature

public static char[] createMethodSignature(char[][] parameterTypes,
                                           char[] returnType)

Creates a method signature from the given parameter and return type signatures. The encoded method signature is dot-based.

Parameters:

parameterTypes - the list of parameter type signatures

returnType - the return type signature

Returns:

the encoded method signature

Since:

2.0

createMethodSignature

public static String createMethodSignature(String[] parameterTypes,
                                           String returnType)

Creates a method signature from the given parameter and return type signatures. The encoded method signature is dot-based.

Parameters:

parameterTypes - the list of parameter type signatures

returnType - the return type signature

Returns:

the encoded method signature

createTypeSignature

public static String createTypeSignature(char[] typeName,
                                         boolean isResolved)

Creates a new type signature from the given type name encoded as a character array. This method is equivalent to createTypeSignature(new String(typeName),isResolved), although more efficient for callers with character arrays rather than strings. If the type name is qualified, then it is expected to be dot-based.

Parameters:

typeName - the possibly qualified type name

isResolved - true if the type name is to be considered resolved (for example, a type name from a binary class file), and false if the type name is to be considered unresolved (for example, a type name found in source code)

Returns:

the encoded type signature

See Also:

createTypeSignature(java.lang.String,boolean)

createCharArrayTypeSignature

public static char[] createCharArrayTypeSignature(char[] typeName,
                                                  boolean isResolved)

Creates a new type signature from the given type name encoded as a character array. This method is equivalent to createTypeSignature(new String(typeName),isResolved).toCharArray(), although more efficient for callers with character arrays rather than strings. If the type name is qualified, then it is expected to be dot-based.

Parameters:

typeName - the possibly qualified type name

isResolved - true if the type name is to be considered resolved (for example, a type name from a binary class file), and false if the type name is to be considered unresolved (for example, a type name found in source code)

Returns:

the encoded type signature

Since:

2.0

See Also:

createTypeSignature(java.lang.String,boolean)

createTypeSignature

public static String createTypeSignature(String typeName,
                                         boolean isResolved)

Creates a new type signature from the given type name. If the type name is qualified, then it is expected to be dot-based.

For example:

 
 createTypeSignature("int", hucairz) -> "I"
 createTypeSignature("java.lang.String", true) -> "Ljava.lang.String;"
 createTypeSignature("String", false) -> "QString;"
 createTypeSignature("java.lang.String", false) -> "Qjava.lang.String;"
 createTypeSignature("int []", false) -> "[I"
 
 

Parameters:

typeName - the possibly qualified type name

isResolved - true if the type name is to be considered resolved (for example, a type name from a binary class file), and false if the type name is to be considered unresolved (for example, a type name found in source code)

Returns:

the encoded type signature

getArrayCount

public static int getArrayCount(char[] typeSignature)
                         throws IllegalArgumentException

Returns the array count (array nesting depth) of the given type signature.

Parameters:

typeSignature - the type signature

Returns:

the array nesting depth, or 0 if not an array

Throws:

IllegalArgumentException - if the signature is not syntactically correct

Since:

2.0

getArrayCount

public static int getArrayCount(String typeSignature)
                         throws IllegalArgumentException

Returns the array count (array nesting depth) of the given type signature.

Parameters:

typeSignature - the type signature

Returns:

the array nesting depth, or 0 if not an array

Throws:

IllegalArgumentException - if the signature is not syntactically correct

getElementType

public static char[] getElementType(char[] typeSignature)
                             throws IllegalArgumentException

Returns the type signature without any array nesting.

For example:

 
 getElementType({'[', '[', 'I'}) --> {'I'}.
 
 

Parameters:

typeSignature - the type signature

Returns:

the type signature without arrays

Throws:

IllegalArgumentException - if the signature is not syntactically correct

Since:

2.0

getElementType

public static String getElementType(String typeSignature)
                             throws IllegalArgumentException

Returns the type signature without any array nesting.

For example:

 
 getElementType("[[I") --> "I".
 
 

Parameters:

typeSignature - the type signature

Returns:

the type signature without arrays

Throws:

IllegalArgumentException - if the signature is not syntactically correct

getParameterCount

public static int getParameterCount(char[] methodSignature)
                             throws IllegalArgumentException

Returns the number of parameter types in the given method signature.

Parameters:

methodSignature - the method signature

Returns:

the number of parameters

Throws:

IllegalArgumentException - if the signature is not syntactically correct

Since:

2.0

getParameterCount

public static int getParameterCount(String methodSignature)
                             throws IllegalArgumentException

Returns the number of parameter types in the given method signature.

Parameters:

methodSignature - the method signature

Returns:

the number of parameters

Throws:

IllegalArgumentException - if the signature is not syntactically correct

getParameterTypes

public static char[][] getParameterTypes(char[] methodSignature)
                                  throws IllegalArgumentException

Extracts the parameter type signatures from the given method signature. The method signature is expected to be dot-based.

Parameters:

methodSignature - the method signature

Returns:

the list of parameter type signatures

Throws:

IllegalArgumentException - if the signature is syntactically incorrect

Since:

2.0

getParameterTypes

public static String[] getParameterTypes(String methodSignature)
                                  throws IllegalArgumentException

Extracts the parameter type signatures from the given method signature. The method signature is expected to be dot-based.

Parameters:

methodSignature - the method signature

Returns:

the list of parameter type signatures

Throws:

IllegalArgumentException - if the signature is syntactically incorrect

getQualifier

public static char[] getQualifier(char[] name)

Returns a char array containing all but the last segment of the given dot-separated qualified name. Returns the empty char array if it is not qualified.

For example:

 
 getQualifier({'j', 'a', 'v', 'a', '.', 'l', 'a', 'n', 'g', '.', 'O', 'b', 'j', 'e', 'c', 't'}) -> {'j', 'a', 'v', 'a', '.', 'l', 'a', 'n', 'g'}
 getQualifier({'O', 'u', 't', 'e', 'r', '.', 'I', 'n', 'n', 'e', 'r'}) -> {'O', 'u', 't', 'e', 'r'}
 
 

Parameters:

name - the name

Returns:

the qualifier prefix, or the empty char array if the name contains no dots

Since:

2.0

getQualifier

public static String getQualifier(String name)

Returns a string containing all but the last segment of the given dot-separated qualified name. Returns the empty string if it is not qualified.

For example:

 
 getQualifier("java.lang.Object") -> "java.lang"
 getQualifier("Outer.Inner") -> "Outer"
 
 

Parameters:

name - the name

Returns:

the qualifier prefix, or the empty string if the name contains no dots

getReturnType

public static char[] getReturnType(char[] methodSignature)
                            throws IllegalArgumentException

Extracts the return type from the given method signature. The method signature is expected to be dot-based.

Parameters:

methodSignature - the method signature

Returns:

the type signature of the return type

Throws:

IllegalArgumentException - if the signature is syntactically incorrect

Since:

2.0

getReturnType

public static String getReturnType(String methodSignature)
                            throws IllegalArgumentException

Extracts the return type from the given method signature. The method signature is expected to be dot-based.

Parameters:

methodSignature - the method signature

Returns:

the type signature of the return type

Throws:

IllegalArgumentException - if the signature is syntactically incorrect

getSimpleName

public static char[] getSimpleName(char[] name)

Returns the last segment of the given dot-separated qualified name. Returns the given name if it is not qualified.

For example:

 
 getSimpleName({'j', 'a', 'v', 'a', '.', 'l', 'a', 'n', 'g', '.', 'O', 'b', 'j', 'e', 'c', 't'}) -> {'O', 'b', 'j', 'e', 'c', 't'}
 
 

Parameters:

name - the name

Returns:

the last segment of the qualified name

Since:

2.0

getSimpleName

public static String getSimpleName(String name)

Returns the last segment of the given dot-separated qualified name. Returns the given name if it is not qualified.

For example:

 
 getSimpleName("java.lang.Object") -> "Object"
 
 

Parameters:

name - the name

Returns:

the last segment of the qualified name

getSimpleNames

public static char[][] getSimpleNames(char[] name)

Returns all segments of the given dot-separated qualified name. Returns an array with only the given name if it is not qualified. Returns an empty array if the name is empty.

For example:

 
 getSimpleNames({'j', 'a', 'v', 'a', '.', 'l', 'a', 'n', 'g', '.', 'O', 'b', 'j', 'e', 'c', 't'}) -> {{'j', 'a', 'v', 'a'}, {'l', 'a', 'n', 'g'}, {'O', 'b', 'j', 'e', 'c', 't'}}
 getSimpleNames({'O', 'b', 'j', 'e', 'c', 't'}) -> {{'O', 'b', 'j', 'e', 'c', 't'}}
 getSimpleNames("") -> {}
 
 

Parameters:

name - the name

Returns:

the list of simple names, possibly empty

Since:

2.0

getSimpleNames

public static String[] getSimpleNames(String name)

Returns all segments of the given dot-separated qualified name. Returns an array with only the given name if it is not qualified. Returns an empty array if the name is empty.

For example:

 
 getSimpleNames("java.lang.Object") -> {"java", "lang", "Object"}
 getSimpleNames("Object") -> {"Object"}
 getSimpleNames("") -> {}
 
 

Parameters:

name - the name

Returns:

the list of simple names, possibly empty

toCharArray

public static char[] toCharArray(char[] methodSignature,
                                 char[] methodName,
                                 char[][] parameterNames,
                                 boolean fullyQualifyTypeNames,
                                 boolean includeReturnType)

Converts the given method signature to a readable form. The method signature is expected to be dot-based.

For example:

 
 toString("([Ljava.lang.String;)V", "main", new String[] {"args"}, false, true) -> "void main(String[] args)"
 
 

Parameters:

methodSignature - the method signature to convert

methodName - the name of the method to insert in the result, or null if no method name is to be included

parameterNames - the parameter names to insert in the result, or null if no parameter names are to be included; if supplied, the number of parameter names must match that of the method signature

fullyQualifyTypeNames - true if type names should be fully qualified, and false to use only simple names

includeReturnType - true if the return type is to be included

Returns:

the char array representation of the method signature

Since:

2.0

toCharArray

public static char[] toCharArray(char[] signature)
                          throws IllegalArgumentException

Converts the given type signature to a readable string. The signature is expected to be dot-based.

For example:

 
 toString({'[', 'L', 'j', 'a', 'v', 'a', '.', 'l', 'a', 'n', 'g', '.', 'S', 't', 'r', 'i', 'n', 'g', ';'}) -> {'j', 'a', 'v', 'a', '.', 'l', 'a', 'n', 'g', '.', 'S', 't', 'r', 'i', 'n', 'g', '[', ']'}
 toString({'I'}) -> {'i', 'n', 't'}
 
 

Note: This method assumes that a type signature containing a '$' is an inner type signature. While this is correct in most cases, someone could define a non-inner type name containing a '$'. Handling this correctly in all cases would have required resolving the signature, which generally not feasible.

Parameters:

signature - the type signature

Returns:

the string representation of the type

Throws:

IllegalArgumentException - if the signature is not syntactically correct

Since:

2.0

toQualifiedName

public static char[] toQualifiedName(char[][] segments)

Converts the given array of qualified name segments to a qualified name.

For example:

 
 toQualifiedName({{'j', 'a', 'v', 'a'}, {'l', 'a', 'n', 'g'}, {'O', 'b', 'j', 'e', 'c', 't'}}) -> {'j', 'a', 'v', 'a', '.', 'l', 'a', 'n', 'g', '.', 'O', 'b', 'j', 'e', 'c', 't'}
 toQualifiedName({{'O', 'b', 'j', 'e', 'c', 't'}}) -> {'O', 'b', 'j', 'e', 'c', 't'}
 toQualifiedName({{}}) -> {}
 
 

Parameters:

segments - the list of name segments, possibly empty

Returns:

the dot-separated qualified name, or the empty string

Since:

2.0

toQualifiedName

public static String toQualifiedName(String[] segments)

Converts the given array of qualified name segments to a qualified name.

For example:

 
 toQualifiedName(new String[] {"java", "lang", "Object"}) -> "java.lang.Object"
 toQualifiedName(new String[] {"Object"}) -> "Object"
 toQualifiedName(new String[0]) -> ""
 
 

Parameters:

segments - the list of name segments, possibly empty

Returns:

the dot-separated qualified name, or the empty string

toString

public static String toString(String signature)
                       throws IllegalArgumentException

Converts the given type signature to a readable string. The signature is expected to be dot-based.

For example:

 
 toString("[Ljava.lang.String;") -> "java.lang.String[]"
 toString("I") -> "int"
 
 

Note: This method assumes that a type signature containing a '$' is an inner type signature. While this is correct in most cases, someone could define a non-inner type name containing a '$'. Handling this correctly in all cases would have required resolving the signature, which generally not feasible.

Parameters:

signature - the type signature

Returns:

the string representation of the type

Throws:

IllegalArgumentException - if the signature is not syntactically correct

toString

public static String toString(String methodSignature,
                              String methodName,
                              String[] parameterNames,
                              boolean fullyQualifyTypeNames,
                              boolean includeReturnType)

Converts the given method signature to a readable string. The method signature is expected to be dot-based.

For example:

 
 toString("([Ljava.lang.String;)V", "main", new String[] {"args"}, false, true) -> "void main(String[] args)"
 
 

Parameters:

methodSignature - the method signature to convert

methodName - the name of the method to insert in the result, or null if no method name is to be included

parameterNames - the parameter names to insert in the result, or null if no parameter names are to be included; if supplied, the number of parameter names must match that of the method signature

fullyQualifyTypeNames - true if type names should be fully qualified, and false to use only simple names

includeReturnType - true if the return type is to be included

Returns:

the string representation of the method signature