Package gnu.jel

Class ClassFile

  • All Implemented Interfaces:
    java.lang.Cloneable

    public class ClassFile
    extends java.lang.Object
    implements java.lang.Cloneable
    This class represents a classfile image in JEL.
    • Constructor Summary

      Constructors 
      Constructor Description
      ClassFile​(int modifiers, java.lang.String name, java.lang.Class<?> superClass, java.lang.Class[] interfaces, LocalField[] fields)
      Starts creation of a new class file.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      ClassFile clone()
      Makes a clone of this object.
      void code​(long op)
      code up to 8 operations.
      void codeB​(long op)  
      void codeLDC​(java.lang.Object o, int primitiveID)
      generates code for code loading constant of primitive type or string.
      void codeM​(java.lang.reflect.Member m)  
      byte[] getImage()
      Finishes class and returns the resulting bytecode.
      int getIndex​(java.lang.Object item, int typeid)
      Used to determine an old CP index or to create a new one for an item.
      void newMethod​(LocalMethod m, java.lang.Class[] vars)
      Starts a new method of this class.
      void noteStk​(int s, int a)
      Notes removal of typeID s and subsequent addition of typeID a to Java stack.
      • Methods inherited from class java.lang.Object

        equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • ClassFile

        public ClassFile​(int modifiers,
                         java.lang.String name,
                         java.lang.Class<?> superClass,
                         java.lang.Class[] interfaces,
                         LocalField[] fields)
        Starts creation of a new class file.

        Sizes of fAccess, fNames and fTypes arrays must be the same.

        Parameters:
        modifiers - sum of one or more of PUBLIC, FINAL, INTERFACE, ABSTRACT constants of java.lang.reflect.Modifier
        name - is the name of new class (must be in Java historical form, i.e. with dots replaced by slashes '/')
        superClass - is the superclass of this class
        interfaces - array of interfaces this class implements
        fields - fields this class will have
    • Method Detail

      • clone

        public ClassFile clone()
        Makes a clone of this object.

        This is used in JEL to avoid step-by step creation of service methods of gnu.jel.CompiledExpression (, getType, ...). They are created only once, and then the resulting ClassFile is cloned at the point, when it is ready to accept the code for evaluation method.

        Overrides:
        clone in class java.lang.Object
        Returns:
        a clone of this object
      • newMethod

        public void newMethod​(LocalMethod m,
                              java.lang.Class[] vars)
        Starts a new method of this class.
        Parameters:
        m - method descriptor.
        vars - types of local variables by number.
      • getImage

        public byte[] getImage()
        Finishes class and returns the resulting bytecode.
        Returns:
        array of bytes of the resulting *.class file.
      • noteStk

        public void noteStk​(int s,
                            int a)
        Notes removal of typeID s and subsequent addition of typeID a to Java stack.

        If either is negative the corresponding operation (addition/removal) is skipped. This method is needed to allow ClassFile to compute the maximum stack occupation for the generated code. It is responsibility of the user (of this class) to call noteStk() each time the stack is changed from within the code.

        Parameters:
        s - typeid to be put on stack (-1 if none).
        a - typeid to be taken off Java stack (-1 if none).
      • codeB

        public final void codeB​(long op)
      • codeM

        public final void codeM​(java.lang.reflect.Member m)
      • code

        public final void code​(long op)
        code up to 8 operations.

        Additionally to Java bytecodes this method accepts (and interprets) some more commands. See the implementation.

        Parameters:
        op - operations to code (least significant bytes coded first).
      • codeLDC

        public final void codeLDC​(java.lang.Object o,
                                  int primitiveID)
        generates code for code loading constant of primitive type or string.
        Parameters:
        o - reflection object or String containing the constant
        primitiveID - type ID to save lookups.
      • getIndex

        public int getIndex​(java.lang.Object item,
                            int typeid)
        Used to determine an old CP index or to create a new one for an item.
        Parameters:
        item - an item to create or get an index for
        typeid - identifies type of argument to avoid linear searches
        Returns:
        index for an item (negative if it has to be written)