Package org.apache.bcel.classfile

Class Utility

java.lang.Object

org.apache.bcel.classfile.Utility

public abstract class Utility
extends java.lang.Object

Utility functions that do not really belong to any class in particular.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	Utility.JavaReader	Decode characters into bytes.
private static class	Utility.JavaWriter	Encode bytes into valid Java identifier characters.

Field Summary

Fields

Modifier and Type	Field	Description
private static int[]	CHAR_MAP
private static java.lang.ThreadLocal<java.lang.Integer>	CONSUMER_CHARS
private static char	ESCAPE_CHAR
private static int	FREE_CHARS
private static int[]	MAP_CHAR
private static boolean	wide

Constructor Summary

Constructors

Constructor	Description
Utility()

Method Summary

Modifier and Type	Method	Description
static java.lang.String	accessToString(int accessFlags)	Convert bit field of flags into string such as 'static final'.
static java.lang.String	accessToString(int accessFlags, boolean forClass)	Convert bit field of flags into string such as 'static final'.
private static short	byteToShort(byte b)	Convert (signed) byte to (unsigned) short value, that is, all negative values become positive.
static java.lang.String	classOrInterface(int accessFlags)
static int	clearBit(int flag, int i)
static java.lang.String	codeToString(byte[] code, ConstantPool constantPool, int index, int length)
static java.lang.String	codeToString(byte[] code, ConstantPool constantPool, int index, int length, boolean verbose)	Disassemble a byte array of JVM byte codes starting from code line 'index' and return the disassembled string representation.
static java.lang.String	codeToString(ByteSequence bytes, ConstantPool constantPool)
static java.lang.String	codeToString(ByteSequence bytes, ConstantPool constantPool, boolean verbose)	Disassemble a stream of byte codes and return the string representation.
static java.lang.String	compactClassName(java.lang.String str)	Shorten long class names, java/lang/String becomes String.
static java.lang.String	compactClassName(java.lang.String str, boolean chopit)	Shorten long class names, java/lang/String becomes java.lang.String, for example.
static java.lang.String	compactClassName(java.lang.String str, java.lang.String prefix, boolean chopit)	Shorten long class name str, that is, chop off the prefix, if the class name starts with this string and the flag chopit is true.
static java.lang.String	convertString(java.lang.String label)	Escape all occurrences of newline chars '\n', quotes \", etc.
private static int	countBrackets(java.lang.String brackets)
static byte[]	decode(java.lang.String s, boolean uncompress)	Decode a string back to a byte array.
static java.lang.String	encode(byte[] bytes, boolean compress)	Encode byte array it into Java identifier string, that is, a string that only contains the following characters: (a, ...
static java.lang.String	fillup(java.lang.String str, int length, boolean leftJustify, char fill)	Fillup char with up to length characters with char 'fill' and justify it left or right.
static java.lang.String	format(int i, int length, boolean leftJustify, char fill)	Return a string for an integer justified left or right and filled up with 'fill' characters if necessary.
static java.lang.String	getSignature(java.lang.String type)	Parse Java type such as "char", or "java.lang.String[]" and return the signature in byte code format, for example "C" or "[Ljava/lang/String;" respectively.
static boolean	isJavaIdentifierPart(char ch)
static boolean	isSet(int flag, int i)
static java.lang.String[]	methodSignatureArgumentTypes(java.lang.String signature)	Converts argument list portion of method signature to string with all class names compacted.
static java.lang.String[]	methodSignatureArgumentTypes(java.lang.String signature, boolean chopit)	Converts argument list portion of method signature to string.
static java.lang.String	methodSignatureReturnType(java.lang.String signature)	Converts return type portion of method signature to string with all class names compacted.
static java.lang.String	methodSignatureReturnType(java.lang.String signature, boolean chopit)	Converts return type portion of method signature to string.
static java.lang.String	methodSignatureToString(java.lang.String signature, java.lang.String name, java.lang.String access)	Converts method signature to string with all class names compacted.
static java.lang.String	methodSignatureToString(java.lang.String signature, java.lang.String name, java.lang.String access, boolean chopit)	Converts method signature to string.
static java.lang.String	methodSignatureToString(java.lang.String signature, java.lang.String name, java.lang.String access, boolean chopit, LocalVariableTable vars)	This method converts a method signature string into a Java type declaration like 'void main(String[])' and throws a 'ClassFormatException' when the parsed type is invalid.
static java.lang.String	methodTypeToSignature(java.lang.String ret, java.lang.String[] argv)	Converts string containing the method return and argument types to a byte code method signature.
static java.lang.String	packageToPath(java.lang.String name)	Converts '.'s to '/'s.
static java.lang.String	pathToPackage(java.lang.String str)	Converts a path to a package name.
private static int	pow2(int n)
static void	printArray(java.io.PrintStream out, java.lang.Object[] obj)
static void	printArray(java.io.PrintWriter out, java.lang.Object[] obj)
static java.lang.String	printArray(java.lang.Object[] obj)
static java.lang.String	printArray(java.lang.Object[] obj, boolean braces)
static java.lang.String	printArray(java.lang.Object[] obj, boolean braces, boolean quote)
static java.lang.String	replace(java.lang.String str, java.lang.String old, java.lang.String new_)	Replace all occurrences of old in str with new.
static short	searchOpcode(java.lang.String name)	Map opcode names to opcode numbers.
static int	setBit(int flag, int i)
static java.lang.String	signatureToString(java.lang.String signature)	Converts a signature to a string with all class names compacted.
static java.lang.String	signatureToString(java.lang.String signature, boolean chopit)	Converts a signature to a string.
static java.lang.String	toHexString(byte[] bytes)	Convert bytes into hexadecimal string
static byte	typeOfMethodSignature(java.lang.String signature)	Return type of method signature as a byte value as defined in Constants
static byte	typeOfSignature(java.lang.String signature)	Return type of signature as a byte value as defined in Constants
private static java.lang.String	typeParamTypesToString(java.lang.String signature, boolean chopit)	Converts a type parameter list signature to a string.
private static java.lang.String	typeParamTypeToString(java.lang.String signature, boolean chopit)	Converts a type parameter signature to a string.
private static java.lang.String	typeSignaturesToString(java.lang.String signature, boolean chopit, char term)	Converts a list of type signatures to a string.
static java.lang.String	typeSignatureToString(java.lang.String signature, boolean chopit)	This method converts a type signature string into a Java type declaration such as 'String[]' and throws a 'ClassFormatException' when the parsed type is invalid.
private static int	unwrap(java.lang.ThreadLocal<java.lang.Integer> tl)
private static void	wrap(java.lang.ThreadLocal<java.lang.Integer> tl, int value)

Methods inherited from class java.lang.Object

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

Field Detail

CONSUMER_CHARS

private static final java.lang.ThreadLocal<java.lang.Integer> CONSUMER_CHARS

wide

private static boolean wide

FREE_CHARS

private static final int FREE_CHARS

See Also:

Constant Field Values

CHAR_MAP

private static final int[] CHAR_MAP

MAP_CHAR

private static final int[] MAP_CHAR

ESCAPE_CHAR

private static final char ESCAPE_CHAR

See Also:

Constant Field Values

Constructor Detail

Utility

public Utility()

Method Detail

accessToString

public static java.lang.String accessToString(int accessFlags)

Convert bit field of flags into string such as 'static final'.

Parameters:

accessFlags - Access flags.

Returns:

String representation of flags.

accessToString

public static java.lang.String accessToString(int accessFlags,
                                              boolean forClass)

Convert bit field of flags into string such as 'static final'.

Special case: Classes compiled with new compilers and with the 'ACC_SUPER' flag would be said to be "synchronized". This is because SUN used the same value for the flags 'ACC_SUPER' and 'ACC_SYNCHRONIZED'.

Parameters:

accessFlags - Access flags.

forClass - access flags are for class qualifiers ?.

Returns:

String representation of flags.

byteToShort

private static short byteToShort(byte b)

Convert (signed) byte to (unsigned) short value, that is, all negative values become positive.

classOrInterface

public static java.lang.String classOrInterface(int accessFlags)

Parameters:

accessFlags - the class flags.

Returns:

"class" or "interface", depending on the ACC_INTERFACE flag.

clearBit

public static int clearBit(int flag,
                           int i)

Returns:

'flag' with bit 'i' set to 0.

codeToString

public static java.lang.String codeToString(byte[] code,
                                            ConstantPool constantPool,
                                            int index,
                                            int length)

codeToString

public static java.lang.String codeToString(byte[] code,
                                            ConstantPool constantPool,
                                            int index,
                                            int length,
                                            boolean verbose)

Disassemble a byte array of JVM byte codes starting from code line 'index' and return the disassembled string representation. Decode only 'num' opcodes (including their operands), use -1 if you want to decompile everything.

Parameters:

code - byte code array.

constantPool - Array of constants.

index - offset in 'code' array (number of opcodes, not bytes!).

length - number of opcodes to decompile, -1 for all.

verbose - be verbose, for example print constant pool index.

Returns:

String representation of byte codes.

codeToString

public static java.lang.String codeToString(ByteSequence bytes,
                                            ConstantPool constantPool)
                                     throws java.io.IOException

Throws:

java.io.IOException

codeToString

public static java.lang.String codeToString(ByteSequence bytes,
                                            ConstantPool constantPool,
                                            boolean verbose)
                                     throws java.io.IOException

Disassemble a stream of byte codes and return the string representation.

Parameters:

bytes - stream of bytes.

constantPool - Array of constants.

verbose - be verbose, for example print constant pool index.

Returns:

String representation of byte code.

Throws:

java.io.IOException - if a failure from reading from the bytes argument occurs

compactClassName

public static java.lang.String compactClassName(java.lang.String str)

Shorten long class names, java/lang/String becomes String.

Parameters:

str - The long class name.

Returns:

Compacted class name.

compactClassName

public static java.lang.String compactClassName(java.lang.String str,
                                                boolean chopit)

Shorten long class names, java/lang/String becomes java.lang.String, for example. If chopit is true the prefix java.lang is also removed.

Parameters:

str - The long class name.

chopit - flag that determines whether chopping is executed or not.

Returns:

Compacted class name.

compactClassName

public static java.lang.String compactClassName(java.lang.String str,
                                                java.lang.String prefix,
                                                boolean chopit)

Shorten long class name str, that is, chop off the prefix, if the class name starts with this string and the flag chopit is true. Slashes / are converted to dots ..

Parameters:

str - The long class name.

prefix - The prefix the get rid off.

chopit - flag that determines whether chopping is executed or not.

Returns:

Compacted class name.

convertString

public static java.lang.String convertString(java.lang.String label)

Escape all occurrences of newline chars '\n', quotes \", etc.

countBrackets

private static int countBrackets(java.lang.String brackets)

decode

public static byte[] decode(java.lang.String s,
                            boolean uncompress)
                     throws java.io.IOException

Decode a string back to a byte array.

Parameters:

s - the string to convert.

uncompress - use gzip to uncompress the stream of bytes.

Throws:

java.io.IOException - if there's a gzip exception

encode

public static java.lang.String encode(byte[] bytes,
                                      boolean compress)
                               throws java.io.IOException

Encode byte array it into Java identifier string, that is, a string that only contains the following characters: (a, ... z, A, ... Z, 0, ... 9, _, $). The encoding algorithm itself is not too clever: if the current byte's ASCII value already is a valid Java identifier part, leave it as it is. Otherwise it writes the escape character($) followed by:

• the ASCII value as a hexadecimal string, if the value is not in the range 200..247
• a Java identifier char not used in a lowercase hexadecimal string, if the value is in the range 200..247

This operation inflates the original byte array by roughly 40-50%

Parameters:

bytes - the byte array to convert.

compress - use gzip to minimize string.

Throws:

java.io.IOException - if there's a gzip exception

fillup

public static java.lang.String fillup(java.lang.String str,
                                      int length,
                                      boolean leftJustify,
                                      char fill)

Fillup char with up to length characters with char 'fill' and justify it left or right.

Parameters:

str - string to format.

length - length of desired string.

leftJustify - format left or right.

fill - fill character.

Returns:

formatted string.

format

public static java.lang.String format(int i,
                                      int length,
                                      boolean leftJustify,
                                      char fill)

Return a string for an integer justified left or right and filled up with 'fill' characters if necessary.

Parameters:

i - integer to format.

length - length of desired string.

leftJustify - format left or right.

fill - fill character.

Returns:

formatted int.

getSignature

public static java.lang.String getSignature(java.lang.String type)

Parse Java type such as "char", or "java.lang.String[]" and return the signature in byte code format, for example "C" or "[Ljava/lang/String;" respectively.

Parameters:

type - Java type.

Returns:

byte code signature.

isJavaIdentifierPart

public static boolean isJavaIdentifierPart(char ch)

Parameters:

ch - the character to test if it's part of an identifier.

Returns:

true, if character is one of (a, ... z, A, ... Z, 0, ... 9, _).

isSet

public static boolean isSet(int flag,
                            int i)

Returns:

true, if bit 'i' in 'flag' is set.

methodSignatureArgumentTypes

public static java.lang.String[] methodSignatureArgumentTypes(java.lang.String signature)
                                                       throws ClassFormatException

Converts argument list portion of method signature to string with all class names compacted.

Parameters:

signature - Method signature.

Returns:

String Array of argument types.

Throws:

ClassFormatException - if a class is malformed or cannot be interpreted as a class file

methodSignatureArgumentTypes

public static java.lang.String[] methodSignatureArgumentTypes(java.lang.String signature,
                                                              boolean chopit)
                                                       throws ClassFormatException

Converts argument list portion of method signature to string.

Parameters:

signature - Method signature.

chopit - flag that determines whether chopping is executed or not.

Returns:

String Array of argument types.

Throws:

ClassFormatException - if a class is malformed or cannot be interpreted as a class file

methodSignatureReturnType

public static java.lang.String methodSignatureReturnType(java.lang.String signature)
                                                  throws ClassFormatException

Converts return type portion of method signature to string with all class names compacted.

Parameters:

signature - Method signature.

Returns:

String representation of method return type.

Throws:

ClassFormatException - if a class is malformed or cannot be interpreted as a class file

methodSignatureReturnType

public static java.lang.String methodSignatureReturnType(java.lang.String signature,
                                                         boolean chopit)
                                                  throws ClassFormatException

Converts return type portion of method signature to string.

Parameters:

signature - Method signature.

chopit - flag that determines whether chopping is executed or not.

Returns:

String representation of method return type.

Throws:

ClassFormatException - if a class is malformed or cannot be interpreted as a class file

methodSignatureToString

public static java.lang.String methodSignatureToString(java.lang.String signature,
                                                       java.lang.String name,
                                                       java.lang.String access)

Converts method signature to string with all class names compacted.

Parameters:

signature - to convert.

name - of method.

access - flags of method.

Returns:

Human readable signature.

methodSignatureToString

public static java.lang.String methodSignatureToString(java.lang.String signature,
                                                       java.lang.String name,
                                                       java.lang.String access,
                                                       boolean chopit)

Converts method signature to string.

Parameters:

signature - to convert.

name - of method.

access - flags of method.

chopit - flag that determines whether chopping is executed or not.

Returns:

Human readable signature.

methodSignatureToString

public static java.lang.String methodSignatureToString(java.lang.String signature,
                                                       java.lang.String name,
                                                       java.lang.String access,
                                                       boolean chopit,
                                                       LocalVariableTable vars)
                                                throws ClassFormatException

This method converts a method signature string into a Java type declaration like 'void main(String[])' and throws a 'ClassFormatException' when the parsed type is invalid.

Parameters:

signature - Method signature.

name - Method name.

access - Method access rights.

chopit - flag that determines whether chopping is executed or not.

vars - the LocalVariableTable for the method.

Returns:

Java type declaration.

Throws:

ClassFormatException - if a class is malformed or cannot be interpreted as a class file

methodTypeToSignature

public static java.lang.String methodTypeToSignature(java.lang.String ret,
                                                     java.lang.String[] argv)
                                              throws ClassFormatException

Converts string containing the method return and argument types to a byte code method signature.

Parameters:

ret - Return type of method.

argv - Types of method arguments.

Returns:

Byte code representation of method signature.

Throws:

ClassFormatException - if the signature is for Void

packageToPath

public static java.lang.String packageToPath(java.lang.String name)

Converts '.'s to '/'s.

Parameters:

name - Source.

Returns:

converted value.

Since:

6.7.0

pathToPackage

public static java.lang.String pathToPackage(java.lang.String str)

Converts a path to a package name.

Parameters:

str - the source path.

Returns:

a package name.

Since:

6.6.0

pow2

private static int pow2(int n)

printArray

public static java.lang.String printArray(java.lang.Object[] obj)

printArray

public static java.lang.String printArray(java.lang.Object[] obj,
                                          boolean braces)

printArray

public static java.lang.String printArray(java.lang.Object[] obj,
                                          boolean braces,
                                          boolean quote)

printArray

public static void printArray(java.io.PrintStream out,
                              java.lang.Object[] obj)

printArray

public static void printArray(java.io.PrintWriter out,
                              java.lang.Object[] obj)

replace

public static java.lang.String replace(java.lang.String str,
                                       java.lang.String old,
                                       java.lang.String new_)

Replace all occurrences of old in str with new.

Parameters:

str - String to permute.

old - String to be replaced.

new_ - Replacement string.

Returns:

new String object.

searchOpcode

public static short searchOpcode(java.lang.String name)

Map opcode names to opcode numbers. E.g., return Constants.ALOAD for "aload".

Parameters:

name - The opcode name.

Returns:

the value.

setBit

public static int setBit(int flag,
                         int i)

Returns:

'flag' with bit 'i' set to 1.

signatureToString

public static java.lang.String signatureToString(java.lang.String signature)

Converts a signature to a string with all class names compacted. Class, Method and Type signatures are supported. Enum and Interface signatures are not supported.

Parameters:

signature - signature to convert.

Returns:

String containg human readable signature.

signatureToString

public static java.lang.String signatureToString(java.lang.String signature,
                                                 boolean chopit)

Converts a signature to a string. Class, Method and Type signatures are supported. Enum and Interface signatures are not supported.

Parameters:

signature - signature to convert.

chopit - flag that determines whether chopping is executed or not.

Returns:

String containg human readable signature.

toHexString

public static java.lang.String toHexString(byte[] bytes)

Convert bytes into hexadecimal string

Parameters:

bytes - an array of bytes to convert to hexadecimal.

Returns:

bytes as hexadecimal string, for example 00 fa 12 ...

typeOfMethodSignature

public static byte typeOfMethodSignature(java.lang.String signature)
                                  throws ClassFormatException

Return type of method signature as a byte value as defined in Constants

Parameters:

signature - in format described above.

Returns:

type of method signature.

Throws:

ClassFormatException - if signature is not a method signature

See Also:

Const

typeOfSignature

public static byte typeOfSignature(java.lang.String signature)
                            throws ClassFormatException

Return type of signature as a byte value as defined in Constants

Parameters:

signature - in format described above.

Returns:

type of signature.

Throws:

ClassFormatException - if signature isn't a known type

See Also:

Const

typeParamTypesToString

private static java.lang.String typeParamTypesToString(java.lang.String signature,
                                                       boolean chopit)

Converts a type parameter list signature to a string.

Parameters:

signature - signature to convert.

chopit - flag that determines whether chopping is executed or not.

Returns:

String containg human readable signature.

typeParamTypeToString

private static java.lang.String typeParamTypeToString(java.lang.String signature,
                                                      boolean chopit)

Converts a type parameter signature to a string.

Parameters:

signature - signature to convert.

chopit - flag that determines whether chopping is executed or not.

Returns:

String containg human readable signature.

typeSignaturesToString

private static java.lang.String typeSignaturesToString(java.lang.String signature,
                                                       boolean chopit,
                                                       char term)

Converts a list of type signatures to a string.

Parameters:

signature - signature to convert.

chopit - flag that determines whether chopping is executed or not.

term - character indicating the end of the list.

Returns:

String containg human readable signature.

typeSignatureToString

public static java.lang.String typeSignatureToString(java.lang.String signature,
                                                     boolean chopit)
                                              throws ClassFormatException

This method converts a type signature string into a Java type declaration such as 'String[]' and throws a 'ClassFormatException' when the parsed type is invalid.

Parameters:

signature - type signature.

chopit - flag that determines whether chopping is executed or not.

Returns:

string containing human readable type signature.

Throws:

ClassFormatException - if a class is malformed or cannot be interpreted as a class file

Since:

6.4.0

unwrap

private static int unwrap(java.lang.ThreadLocal<java.lang.Integer> tl)

wrap

private static void wrap(java.lang.ThreadLocal<java.lang.Integer> tl,
                         int value)