org.gjt.jclasslib.structures
Class AbstractStructure

java.lang.Object
  |
  +--org.gjt.jclasslib.structures.AbstractStructure

Direct Known Subclasses:

AbstractStructureWithAttributes, CPInfo, ExceptionTableEntry, InnerClassesEntry, LineNumberTableEntry, LocalVariableTableEntry

public abstract class AbstractStructure

extends Object

Base class for all structures defined in the class file format.

Provides common services such as reading, writing and debugging.

Version:

$Revision: 1.4 $ $Date: 2003/08/18 07:52:54 $

Author:

Ingo Kegel

Field Summary

protected ClassFile	classFile Parent class file for this structure.
protected boolean	debug Flag for debugging while reading and writing class files.
static String	SYSTEM_PROPERTY_DEBUG Set this JVM System property to true to switch on debugging for reading and writing class files.

Constructor Summary

protected

AbstractStructure() Constructor.

Method Summary

protected void	debug(String message) Utility method for derived structures.
ClassFile	getClassFile() Get parent class file.
boolean	getDebug() Get the debug mode for this structure.
protected int	getLength(Object array) Utility method for derived structures.
protected String	printAccessFlags(int accessFlags) Utility method for derived structures.
protected String	printAccessFlagsVerbose(int accessFlags) Utility method for derived structures.
protected String	printBytes(int bytes) Utility method for derived structures.
void	read(DataInput in) Read this structure from the given DataInput.
void	setClassFile(ClassFile classFile) Set parent class file.
void	setDebug(boolean debug) Set the debug mode for this structure.
void	write(DataOutput out) Write this structure to the given DataOutput.

Methods inherited from class java.lang.Object

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

Field Detail

SYSTEM_PROPERTY_DEBUG

public static final String SYSTEM_PROPERTY_DEBUG

Set this JVM System property to true to switch on debugging for reading and writing class files.

See Also:

Constant Field Values

classFile

protected ClassFile classFile

Parent class file for this structure. Null for a ClassFile structure.

debug

protected boolean debug

Flag for debugging while reading and writing class files.

Constructor Detail

AbstractStructure

protected AbstractStructure()

Constructor.

Method Detail

getClassFile

public ClassFile getClassFile()

Get parent class file.

Returns:

the class file

setClassFile

public void setClassFile(ClassFile classFile)

Set parent class file.

Has to be called at least once on a structure.

Parameters:

classFile - the new parent class file

read

public void read(DataInput in)
          throws InvalidByteCodeException,
                 IOException

Read this structure from the given DataInput.

Excpects DataInput to be in JVM class file format and just before a structure of this kind. No look ahead parsing since the class file format is deterministic.

Parameters:

in - the DataInput from which to read

Throws:

InvalidByteCodeException - if the byte code is invalid

IOException - if an exception occurs with the DataInput

write

public void write(DataOutput out)
           throws InvalidByteCodeException,
                  IOException

Write this structure to the given DataOutput.

The written bytes are in JVM class file format.

Parameters:

out - the DataOutput to which to write

Throws:

InvalidByteCodeException - if the structure is internally inconsistent

IOException - if an exception occurs with the DataOutput

getDebug

public boolean getDebug()

Get the debug mode for this structure.

Returns:

whether debug is on or not

setDebug

public void setDebug(boolean debug)

Set the debug mode for this structure.

Parameters:

debug - the new debug mode

getLength

protected int getLength(Object array)

Utility method for derived structures. Get the length of an arbitrary array which may hold primitive types or reference types or may be null.

Parameters:

array - the array for which the length is requested

Returns:

the length

debug

protected void debug(String message)

Utility method for derived structures. Dump a specific debug message.

Parameters:

message - the debug message

printBytes

protected String printBytes(int bytes)

Utility method for derived structures. Print an int value as a hex string.

Parameters:

bytes - the int value to print as a hex string

Returns:

the hex string

printAccessFlags

protected String printAccessFlags(int accessFlags)

Utility method for derived structures. Print an access flag or an unsigned short value as a hex string.

Parameters:

accessFlags - the unsigned short value to print as a hex string

Returns:

the hex string

printAccessFlagsVerbose

protected String printAccessFlagsVerbose(int accessFlags)

Utility method for derived structures. Print an access flag as a space separated list of verbose java access modifiers.

Parameters:

accessFlags - the unsigned short value to print as a hex string

Returns:

the hex string