File	Doc	Category	Size	Date	Package
ClassParser.java	API Doc	Java SE 5 API	11544	Fri Aug 26 14:55:16 BST 2005	com.sun.org.apache.bcel.internal.classfile

ClassParser

• java.lang.Object

Fields Summary
private DataInputStream	file
private ZipFile	zip
private String	file_name
private int	class_name_index
private int	superclass_name_index
private int	major
private int	minor
private int	access_flags
private int[]	interfaces
private ConstantPool	constant_pool
private Field[]	fields
private Method[]	methods
private Attribute[]	attributes
private boolean	is_zip
private static final int	BUFSIZE

Constructors Summary
public ClassParser(InputStream file, String file_name) Parse class from the given stream. param file Input stream param file_name File name this.file_name = file_name; String clazz = file.getClass().getName(); // Not a very clean solution ... is_zip = clazz.startsWith("java.util.zip.") || clazz.startsWith("java.util.jar."); if(file instanceof DataInputStream) // Is already a data stream this.file = (DataInputStream)file; else this.file = new DataInputStream(new BufferedInputStream(file, BUFSIZE));
public ClassParser(String file_name) Parse class from given .class file. param file_name file name throw IOException is_zip = false; this.file_name = file_name; file = new DataInputStream(new BufferedInputStream (new FileInputStream(file_name), BUFSIZE));
public ClassParser(String zip_file, String file_name) Parse class from given .class file in a ZIP-archive param file_name file name throw IOException is_zip = true; zip = new ZipFile(zip_file); ZipEntry entry = zip.getEntry(file_name); this.file_name = file_name; file = new DataInputStream(new BufferedInputStream(zip.getInputStream(entry), BUFSIZE));

Methods Summary
public com.sun.org.apache.bcel.internal.classfile.JavaClass	parse() Parse the given Java class file and return an object that represents the contained data, i.e., constants, methods, fields and commands. A ClassFormatError 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). return Class object representing the parsed class file throw IOException throw ClassFormatError /****************** Read headers ********************************/ // Check magic tag of class file readID(); // Get compiler version readVersion(); /****************** Read constant pool and related **************/ // Read constant pool entries readConstantPool(); // Get class information readClassInfo(); // Get interface information, i.e., implemented interfaces readInterfaces(); /****************** Read class fields and methods ***************/ // Read class fields, i.e., the variables of the class readFields(); // Read class methods, i.e., the functions in the class readMethods(); // Read class attributes readAttributes(); // Check for unknown variables //Unknown[] u = Unknown.getUnknownAttributes(); //for(int i=0; i < u.length; i++) // System.err.println("WARNING: " + u[i]); // Everything should have been read now // if(file.available() > 0) { // int bytes = file.available(); // byte[] buf = new byte[bytes]; // file.read(buf); // if(!(is_zip && (buf.length == 1))) { // System.err.println("WARNING: Trailing garbage at end of " + file_name); // System.err.println(bytes + " extra bytes: " + Utility.toHexString(buf)); // } // } // Read everything of interest, so close the file file.close(); if(zip != null) zip.close(); // Return the information we have gathered in a new object return new JavaClass(class_name_index, superclass_name_index, file_name, major, minor, access_flags, constant_pool, interfaces, fields, methods, attributes, is_zip? JavaClass.ZIP : JavaClass.FILE);
private final void	readAttributes() Read information about the attributes of the attributes of the class. throw IOException throw ClassFormatError int attributes_count; attributes_count = file.readUnsignedShort(); attributes = new Attribute[attributes_count]; for(int i=0; i < attributes_count; i++) attributes[i] = Attribute.readAttribute(file, constant_pool);
private final void	readClassInfo() Read information about the class and its super class. throw IOException throw ClassFormatError access_flags = file.readUnsignedShort(); /* Interfaces are implicitely abstract, the flag should be set * according to the JVM specification. */ if((access_flags & Constants.ACC_INTERFACE) != 0) access_flags |= Constants.ACC_ABSTRACT; if(((access_flags & Constants.ACC_ABSTRACT) != 0) && ((access_flags & Constants.ACC_FINAL) != 0 )) throw new ClassFormatError("Class can't be both final and abstract"); class_name_index = file.readUnsignedShort(); superclass_name_index = file.readUnsignedShort();
private final void	readConstantPool() Read constant pool entries. throw IOException throw ClassFormatError constant_pool = new ConstantPool(file);
private final void	readFields() Read information about the fields of the class, i.e., its variables. throw IOException throw ClassFormatError int fields_count; fields_count = file.readUnsignedShort(); fields = new Field[fields_count]; for(int i=0; i < fields_count; i++) fields[i] = new Field(file, constant_pool);
private final void	readID() Check whether the header of the file is ok. Of course, this has to be the first action on successive file reads. throw IOException throw ClassFormatError int magic = 0xCAFEBABE; if(file.readInt() != magic) throw new ClassFormatError(file_name + " is not a Java .class file");
private final void	readInterfaces() Read information about the interfaces implemented by this class. throw IOException throw ClassFormatError int interfaces_count; interfaces_count = file.readUnsignedShort(); interfaces = new int[interfaces_count]; for(int i=0; i < interfaces_count; i++) interfaces[i] = file.readUnsignedShort();
private final void	readMethods() Read information about the methods of the class. throw IOException throw ClassFormatError int methods_count; methods_count = file.readUnsignedShort(); methods = new Method[methods_count]; for(int i=0; i < methods_count; i++) methods[i] = new Method(file, constant_pool);
private final void	readVersion() Read major and minor version of compiler which created the file. throw IOException throw ClassFormatError minor = file.readUnsignedShort(); major = file.readUnsignedShort();