edu.wisc.cs.java
Class ClassFile

java.lang.Object
  |
  +--edu.wisc.cs.java.Accessible
        |
        +--edu.wisc.cs.java.ClassFile

public class ClassFile

extends Accessible

This object maintains a Class_file table, as specified by the Java Virtual Machine specification for class files.

Field Summary

protected AttributeInfo[]	attributes An array of AttributeInfo objects which represent the general attributes of thie class.
protected ConstantPool	constants The constant pool for this class.
protected java.util.Vector	fields An array of FieldInfo objects which represent the fields of thie class.
protected java.lang.String	filename The name of the file from which this class was read.
protected char[]	interfaces An array of indeces into the constant pool which are the interfaces directly implemented by this class.
static int	MAGIC All valid classfiles begin with this four byte number.
static int	MAJOR_FILE_VERSION The major file version number this class was designed to read and write.
protected int	major_version The major version number for this class file.
protected java.util.Vector	methods An array of MethodInfo objects which represent the methods of thie class.
static int	MINOR_FILE_VERSION The minor file version number this class was designed to read and write.
protected int	minor_version The minor version number for this class file.
protected char	super_class An index into the constant pool containing the symbolic reference to the super class.
protected char	this_class An index into the constant pool containing the symbolic reference to this class.

Fields inherited from class edu.wisc.cs.java.Accessible

ACC_ABSTRACT, ACC_FINAL, ACC_INTERFACE, ACC_NATIVE, ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC, ACC_STATIC, ACC_SUPER, ACC_SYNCHRONIZED, ACC_TRANSIENT, ACC_VOLATILE, access_flags

Constructor Summary

ClassFile(java.io.File file)
Constructs a new ClassFile object by reading data from the specified file.

Method Summary

FieldInfo	addField(int access, java.lang.String name, java.lang.String desc) Adds a new field to the class with the given access flags, name, and type.
MethodInfo	addMethod(int access, java.lang.String name, java.lang.String desc) Adds a new method to the class with the given access flags, name, and type.
java.lang.String	getClassName() Returns the name of the class.
ConstantPool	getConstantPool() Returns the constant pool for this class.
java.util.Enumeration	getFields() Returns an enumeration containing all of the fields for this class.
java.lang.String	getFileName() Returns the name of the file from which this class was read.
int	getMajorVersion() Returns the major version number of this class file.
java.util.Enumeration	getMethods() Returns an enumeration containing all of the methods for this class.
int	getMinorVersion() Returns the minor version number of this class file.
java.lang.String	getSuperClass() Returns the name of the superclass.
void	printData(java.io.PrintStream out) Writes textual information about the class represented by this ClassFile object to the specified destination.
void	writeClassFile(java.io.File f) Writes a class file according to the Java Virtual Machine specification.

Methods inherited from class edu.wisc.cs.java.Accessible

getFlag, setFlag, unSetFlag

Methods inherited from class java.lang.Object

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

Field Detail

MAGIC

public static final int MAGIC

All valid classfiles begin with this four byte number.

MAJOR_FILE_VERSION

public static final int MAJOR_FILE_VERSION

The major file version number this class was designed to read and write.

MINOR_FILE_VERSION

public static final int MINOR_FILE_VERSION

The minor file version number this class was designed to read and write.

filename

protected java.lang.String filename

The name of the file from which this class was read.

major_version

protected int major_version

The major version number for this class file.

minor_version

protected int minor_version

The minor version number for this class file.

this_class

protected char this_class

An index into the constant pool containing the symbolic reference to this class.

super_class

protected char super_class

An index into the constant pool containing the symbolic reference to the super class.

constants

protected ConstantPool constants

The constant pool for this class.

interfaces

protected char[] interfaces

An array of indeces into the constant pool which are the interfaces directly implemented by this class.

fields

protected java.util.Vector fields

An array of FieldInfo objects which represent the fields of thie class.

methods

protected java.util.Vector methods

An array of MethodInfo objects which represent the methods of thie class.

attributes

protected AttributeInfo[] attributes

An array of AttributeInfo objects which represent the general attributes of thie class.

Constructor Detail

ClassFile

public ClassFile(java.io.File file)
          throws java.io.EOFException

Constructs a new ClassFile object by reading data from the specified file. Note that this file is expected to have been verified as readable by this process by the caller.

Parameters:

filename - String containing the name a path of a class file.

Throws:

java.io.EOFException - if the end of file is encountered unexpectedly.

Method Detail

getFileName

public java.lang.String getFileName()

Returns the name of the file from which this class was read.

Returns:

the name of the file from which this class was read.

getMajorVersion

public int getMajorVersion()

Returns the major version number of this class file.

Returns:

the major version number of this class file.

getMinorVersion

public int getMinorVersion()

Returns the minor version number of this class file.

Returns:

the minor version number of this class file.

getConstantPool

public ConstantPool getConstantPool()

Returns the constant pool for this class.

Returns:

the constant pool for this class.

addField

public FieldInfo addField(int access,
                          java.lang.String name,
                          java.lang.String desc)

Adds a new field to the class with the given access flags, name, and type.

Parameters:

access - a bit field with the desired acess flags set.

name - the name of the new field.

desc - the descriptor for the new field.

Returns:

the new FieldInfo object.

addMethod

public MethodInfo addMethod(int access,
                            java.lang.String name,
                            java.lang.String desc)

Adds a new method to the class with the given access flags, name, and type.

Parameters:

access - a bit field with the desired acess flags set.

name - the name of the new field.

desc - the descriptor for the new field.

Returns:

the new MethodInfo object.

getFields

public java.util.Enumeration getFields()

Returns an enumeration containing all of the fields for this class.

getMethods

public java.util.Enumeration getMethods()

Returns an enumeration containing all of the methods for this class.

getSuperClass

public java.lang.String getSuperClass()

Returns the name of the superclass.

Returns:

a string containing the name of the superclass.

getClassName

public java.lang.String getClassName()

Returns the name of the class.

Returns:

a string containing the name of the class.

writeClassFile

public void writeClassFile(java.io.File f)
                    throws java.io.IOException

Writes a class file according to the Java Virtual Machine specification. Note that it is assumed that the file argument has been ok'ed for writing by the caller.

Parameters:

f - a file object representing the file on disk to write.

Throws:

java.io.IOException - if there is a problem writing the file.

printData

public void printData(java.io.PrintStream out)

Writes textual information about the class represented by this ClassFile object to the specified destination. The destination is usually System.out or System.err. This method is primarily for debugging purposes. Eventually, I would like to turn this into a robust Java disassembler, outputing the data in a format similar to java source code, but substituting the bytecode in the body of the methods.

Parameters:

out - a PrintStream connected to the desired destination.