org.apache.bytecode

Class ClassReader

java.lang.Object

java.io.InputStream

java.io.ByteArrayInputStream

org.apache.bytecode.ClassReader

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

Direct Known Subclasses:

ParamReader

public class ClassReader
extends java.io.ByteArrayInputStream

This is the class file reader for obtaining the parameter names for declared methods in a class. The class must have debugging attributes for us to obtain this information.

This does not work for inherited methods. To obtain parameter names for inherited methods, you must use a paramReader for the class that originally declared the method.

don't get tricky, it's the bare minimum. Instances of this class are not threadsafe -- don't share them.

Field Summary

Fields inherited from class java.io.ByteArrayInputStream

buf, count, mark, pos

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ClassReader(byte[] buf, java.util.Map attrMethods)

Method Summary

Modifier and Type	Method and Description
protected static java.util.Map	findAttributeReaders(java.lang.Class c)
protected static byte[]	getBytes(java.lang.Class c) Loads the bytecode for a given class, by using the class's defining classloader and assuming that for a class named P.C, the bytecodes are in a resource named /P/C.class.
protected static java.lang.String	getSignature(java.lang.reflect.Member method, java.lang.Class[] paramTypes)
protected void	readAttributes() Reads an attributes array.
void	readCode() Reads a code attribute.
protected void	readCpool()
protected int	readInt()
protected int	readShort()
protected java.lang.Class	resolveClass(int i)
protected java.lang.reflect.Field	resolveField(int i)
protected java.lang.reflect.Member	resolveMethod(int index)
protected org.apache.bytecode.ClassReader.NameAndType	resolveNameAndType(int i)
protected java.lang.String	resolveUtf8(int i)
protected void	skipAttributes()
protected void	skipFully(int n) Skips n bytes in the input stream.

Methods inherited from class java.io.ByteArrayInputStream

available, close, mark, markSupported, read, read, reset, skip

Methods inherited from class java.io.InputStream

read

Methods inherited from class java.lang.Object

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

Constructor Detail

ClassReader

protected ClassReader(byte[] buf,
                      java.util.Map attrMethods)

Method Detail

getBytes

protected static byte[] getBytes(java.lang.Class c)
                          throws java.io.IOException

Loads the bytecode for a given class, by using the class's defining classloader and assuming that for a class named P.C, the bytecodes are in a resource named /P/C.class.

Parameters:

c - the class of interest

Returns:

Returns a byte array containing the bytecode

Throws:

java.io.IOException

findAttributeReaders

protected static java.util.Map findAttributeReaders(java.lang.Class c)

getSignature

protected static java.lang.String getSignature(java.lang.reflect.Member method,
                                               java.lang.Class[] paramTypes)

readShort

protected final int readShort()

Returns:

Returns the next unsigned 16 bit value.

readInt

protected final int readInt()

Returns:

Returns the next signed 32 bit value.

skipFully

protected void skipFully(int n)
                  throws java.io.IOException

Skips n bytes in the input stream.

Throws:

java.io.IOException

resolveMethod

protected final java.lang.reflect.Member resolveMethod(int index)
                                                throws java.io.IOException,
                                                       java.lang.ClassNotFoundException,
                                                       java.lang.NoSuchMethodException

Throws:

java.io.IOException

java.lang.ClassNotFoundException

java.lang.NoSuchMethodException

resolveField

protected final java.lang.reflect.Field resolveField(int i)
                                              throws java.io.IOException,
                                                     java.lang.ClassNotFoundException,
                                                     java.lang.NoSuchFieldException

Throws:

java.io.IOException

java.lang.ClassNotFoundException

java.lang.NoSuchFieldException

resolveNameAndType

protected final org.apache.bytecode.ClassReader.NameAndType resolveNameAndType(int i)
                                                                        throws java.io.IOException

Throws:

java.io.IOException

resolveClass

protected final java.lang.Class resolveClass(int i)
                                      throws java.io.IOException,
                                             java.lang.ClassNotFoundException

Throws:

java.io.IOException

java.lang.ClassNotFoundException

resolveUtf8

protected final java.lang.String resolveUtf8(int i)
                                      throws java.io.IOException

Throws:

java.io.IOException

readCpool

protected final void readCpool()
                        throws java.io.IOException

Throws:

java.io.IOException

skipAttributes

protected final void skipAttributes()
                             throws java.io.IOException

Throws:

java.io.IOException

readAttributes

protected final void readAttributes()
                             throws java.io.IOException

Reads an attributes array. The elements of a class file that can contain attributes are: fields, methods, the class itself, and some other types of attributes.

Throws:

java.io.IOException

readCode

public void readCode()
              throws java.io.IOException

Reads a code attribute.

Throws:

java.io.IOException