org.apache.tomcat.util.bcel.classfile
Class Utility

java.lang.Object
  org.apache.tomcat.util.bcel.classfile.Utility

public abstract class Utility
extends Object

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

Version:

$Id: Utility.java 1181133 2011-10-10 18:49:14Z markt $

Author:

M. Dahm

Constructor Summary

Utility()

Method Summary

static String	accessToString(int access_flags) Convert bit field of flags into string such as `static final'.
static String	accessToString(int access_flags, boolean for_class) Convert bit field of flags into string such as `static final'.
static String	classOrInterface(int access_flags)
static String	codeToString(byte[] code, ConstantPool constant_pool, 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 String	codeToString(ByteSequence bytes, ConstantPool constant_pool, boolean verbose) Disassemble a stream of byte codes and return the string representation.
static String	compactClassName(String str) Shorten long class names, java/lang/String becomes String.
static String	compactClassName(String str, boolean chopit) Shorten long class names, java/lang/String becomes java.lang.String, e.g..
static String	compactClassName(String str, String prefix, boolean chopit) Shorten long class name str, i.e., chop off the prefix, if the class name starts with this string and the flag chopit is true.
static String	convertString(String label) Escape all occurences of newline chars '\n', quotes \", etc.
static String	fillup(String str, int length, boolean left_justify, char fill) Fillup char with up to length characters with char `fill' and justify it left or right.
static String	methodSignatureToString(String signature, String name, String access, boolean chopit, LocalVariableTable vars) A returntype signature represents the return value from a method.
static String	replace(String str, String old, String new_) Replace all occurrences of old in str with new.
static String	signatureToString(String signature) Converts signature to string with all class names compacted.
static String	signatureToString(String signature, boolean chopit) The field signature represents the value of an argument to a function or the value of a variable.
static String	toHexString(byte[] bytes) Convert bytes into hexadecimal string

Methods inherited from class java.lang.Object

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

Constructor Detail

Utility

public Utility()

Method Detail

accessToString

public static final String accessToString(int access_flags)

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

Parameters:

access_flags - Access flags

Returns:

String representation of flags

accessToString

public static final String accessToString(int access_flags,
                                          boolean for_class)

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:

access_flags - Access flags

for_class - access flags are for class qualifiers ?

Returns:

String representation of flags

classOrInterface

public static final String classOrInterface(int access_flags)

Parameters:

access_flags - the class flags

Returns:

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

codeToString

public static final String codeToString(byte[] code,
                                        ConstantPool constant_pool,
                                        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

constant_pool - 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, e.g. print constant pool index

Returns:

String representation of byte codes

codeToString

public static final String codeToString(ByteSequence bytes,
                                        ConstantPool constant_pool,
                                        boolean verbose)
                                 throws IOException

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

Parameters:

bytes - stream of bytes

constant_pool - Array of constants

verbose - be verbose, e.g. print constant pool index

Returns:

String representation of byte code

Throws:

IOException - if a failure from reading from the bytes argument occurs

compactClassName

public static final String compactClassName(String str)

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

Parameters:

str - The long class name

Returns:

Compacted class name

compactClassName

public static final String compactClassName(String str,
                                            String prefix,
                                            boolean chopit)

Shorten long class name str, i.e., 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

compactClassName

public static final String compactClassName(String str,
                                            boolean chopit)

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

methodSignatureToString

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

A returntype signature represents the return value from a method. It is a series of bytes in the following grammar: ::= | V The character V indicates that the method returns no value. Otherwise, the signature indicates the type of the return value. An argument signature represents an argument passed to a method: ::= A method signature represents the arguments that the method expects, and the value that it returns. ::= () ::= * This method converts such a 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 -

vars -

Returns:

Java type declaration

Throws:

ClassFormatException

replace

public static final String replace(String str,
                                   String old,
                                   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

signatureToString

public static final String signatureToString(String signature)

Converts signature to string with all class names compacted.

Parameters:

signature - to convert

Returns:

Human readable signature

signatureToString

public static final String signatureToString(String signature,
                                             boolean chopit)

The field signature represents the value of an argument to a function or the value of a variable. It is a series of bytes generated by the following grammar:

  ::= 
       ::= ||
        ::= B|C|D|F|I|J|S|Z
      ::= L;
       ::= [

 The meaning of the base types is as follows:
 B byte signed byte
 C char character
 D double double precision IEEE float
 F float single precision IEEE float
 I int integer
 J long long integer
 L; ... an object of the given class
 S short signed short
 Z boolean true or false
 [ ... array
 

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

Parameters:

signature - Class signature

chopit - Flag that determines whether chopping is executed or not

Returns:

Java type declaration

Throws:

ClassFormatException

toHexString

public static final String toHexString(byte[] bytes)

Convert bytes into hexadecimal string

Parameters:

bytes - an array of bytes to convert to hexadecimal

Returns:

bytes as hexadecimal string, e.g. 00 FA 12 ...

fillup

public static final String fillup(String str,
                                  int length,
                                  boolean left_justify,
                                  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

left_justify - format left or right

fill - fill character

Returns:

formatted string

convertString

public static final String convertString(String label)

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