Package org.apache.bcel.classfile

Class ClassParser

java.lang.Object

org.apache.bcel.classfile.ClassParser

public final class ClassParser
extends Object

Wrapper class that parses a given Java .class file. The method parse returns a JavaClass object on success. When an I/O error or an inconsistency occurs an appropiate exception is propagated back to the caller. The structure and the names comply, except for a few conveniences, exactly with the JVM specification 1.0. See this paper for further details about the structure of a bytecode file.

Field Summary

Fields

Modifier and Type	Field	Description
private int	access_flags
private Attribute[]	attributes
private static final int	BUFSIZE
private int	class_name_index
private ConstantPool	constant_pool
private DataInputStream	dataInputStream
private Field[]	fields
private final String	file_name
private final boolean	fileOwned
private int[]	interfaces
private final boolean	is_zip
private int	major
private Method[]	methods
private int	minor
private int	superclass_name_index
private String	zip_file

Constructor Summary

Constructors

Constructor	Description
ClassParser(InputStream inputStream, String file_name)	Parses class from the given stream.
ClassParser(String file_name)	Parses class from given .class file.
ClassParser(String zip_file, String file_name)	Parses class from given .class file in a ZIP-archive

Method Summary

Modifier and Type	Method	Description
JavaClass	parse()	Parses the given Java class file and return an object that represents the contained data, i.e., constants, methods, fields and commands.
private void	readAttributes()	Reads information about the attributes of the class.
private void	readClassInfo()	Reads information about the class and its super class.
private void	readConstantPool()	Reads constant pool entries.
private void	readFields()	Reads information about the fields of the class, i.e., its variables.
private void	readID()	Checks whether the header of the file is ok.
private void	readInterfaces()	Reads information about the interfaces implemented by this class.
private void	readMethods()	Reads information about the methods of the class.
private void	readVersion()	Reads major and minor version of compiler which created the file.

Methods inherited from class java.lang.Object

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

Field Details

dataInputStream

private DataInputStream dataInputStream

fileOwned

private final boolean fileOwned

file_name

private final String file_name

zip_file

private String zip_file

class_name_index

private int class_name_index

superclass_name_index

private int superclass_name_index

major

private int major

minor

private int minor

access_flags

private int access_flags

interfaces

private int[] interfaces

constant_pool

private ConstantPool constant_pool

fields

private Field[] fields

methods

private Method[] methods

attributes

private Attribute[] attributes

is_zip

private final boolean is_zip

BUFSIZE

private static final int BUFSIZE

See Also:

• Constant Field Values

Constructor Details

ClassParser

public ClassParser(InputStream inputStream,
 String file_name)

Parses class from the given stream.

Parameters:

inputStream - Input stream

file_name - File name

ClassParser

public ClassParser(String file_name)

Parses class from given .class file.

Parameters:

file_name - file name

ClassParser

public ClassParser(String zip_file,
 String file_name)

Parses class from given .class file in a ZIP-archive

Parameters:

zip_file - zip file name

file_name - file name

Method Details

parse

public JavaClass parse()
                throws IOException,
ClassFormatException

Parses the given Java class file and return an object that represents the contained data, i.e., constants, methods, fields and commands. A ClassFormatException is raised, if the file is not a valid .class file. (This does not include verification of the byte code as it is performed by the java interpreter).

Returns:

Class object representing the parsed class file

Throws:

IOException

ClassFormatException

readAttributes

private void readAttributes()
                     throws IOException,
ClassFormatException

Reads information about the attributes of the class.

Throws:

IOException

ClassFormatException

readClassInfo

private void readClassInfo()
                    throws IOException,
ClassFormatException

Reads information about the class and its super class.

Throws:

IOException

ClassFormatException

readConstantPool

private void readConstantPool()
                       throws IOException,
ClassFormatException

Reads constant pool entries.

Throws:

IOException

ClassFormatException

readFields

private void readFields()
                 throws IOException,
ClassFormatException

Reads information about the fields of the class, i.e., its variables.

Throws:

IOException

ClassFormatException

readID

private void readID()
             throws IOException,
ClassFormatException

Checks whether the header of the file is ok. Of course, this has to be the first action on successive file reads.

Throws:

IOException

ClassFormatException

readInterfaces

private void readInterfaces()
                     throws IOException,
ClassFormatException

Reads information about the interfaces implemented by this class.

Throws:

IOException

ClassFormatException

readMethods

private void readMethods()
                  throws IOException,
ClassFormatException

Reads information about the methods of the class.

Throws:

IOException

ClassFormatException

readVersion

private void readVersion()
                  throws IOException,
ClassFormatException

Reads major and minor version of compiler which created the file.

Throws:

IOException

ClassFormatException