Package bsh

Class ClassGeneratorUtil

  • All Implemented Interfaces:
    bsh.org.objectweb.asm.Constants

    public class ClassGeneratorUtil
    extends java.lang.Object
    implements bsh.org.objectweb.asm.Constants
    ClassGeneratorUtil utilizes the ASM (www.objectweb.org) bytecode generator by Eric Bruneton in order to generate class "stubs" for BeanShell at runtime.

    Stub classes contain all of the fields of a BeanShell scripted class as well as two "callback" references to BeanShell namespaces: one for static methods and one for instance methods. Methods of the class are delegators which invoke corresponding methods on either the static or instance bsh object and then unpack and return the results. The static namespace utilizes a static import to delegate variable access to the class' static fields. The instance namespace utilizes a dynamic import (i.e. mixin) to delegate variable access to the class' instance variables.

    Constructors for the class delegate to the static initInstance() method of ClassGeneratorUtil to initialize new instances of the object. initInstance() invokes the instance intializer code (init vars and instance blocks) and then delegates to the corresponding scripted constructor method in the instance namespace. Constructors contain special switch logic which allows the BeanShell to control the calling of alternate constructors (this() or super() references) at runtime.

    Specially named superclass delegator methods are also generated in order to allow BeanShell to access overridden methods of the superclass (which reflection does not normally allow).

    Author:
    Pat Niemeyer
    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static class  ClassGeneratorUtil.ConstructorArgs
      A ConstructorArgs object holds evaluated arguments for a constructor call as well as the index of a possible alternate selector to invoke.
    • Field Summary

      • Fields inherited from interface bsh.org.objectweb.asm.Constants

        AALOAD, AASTORE, ACC_ABSTRACT, ACC_DEPRECATED, ACC_FINAL, ACC_INTERFACE, ACC_NATIVE, ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC, ACC_STATIC, ACC_STRICT, ACC_SUPER, ACC_SYNCHRONIZED, ACC_SYNTHETIC, ACC_TRANSIENT, ACC_VOLATILE, ACONST_NULL, ALOAD, ANEWARRAY, ARETURN, ARRAYLENGTH, ASTORE, ATHROW, BALOAD, BASTORE, BIPUSH, CALOAD, CASTORE, CHECKCAST, D2F, D2I, D2L, DADD, DALOAD, DASTORE, DCMPG, DCMPL, DCONST_0, DCONST_1, DDIV, DLOAD, DMUL, DNEG, DREM, DRETURN, DSTORE, DSUB, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, F2D, F2I, F2L, FADD, FALOAD, FASTORE, FCMPG, FCMPL, FCONST_0, FCONST_1, FCONST_2, FDIV, FLOAD, FMUL, FNEG, FREM, FRETURN, FSTORE, FSUB, GETFIELD, GETSTATIC, GOTO, I2B, I2C, I2D, I2F, I2L, I2S, IADD, IALOAD, IAND, IASTORE, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, ICONST_M1, IDIV, IF_ACMPEQ, IF_ACMPNE, IF_ICMPEQ, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ICMPLT, IF_ICMPNE, IFEQ, IFGE, IFGT, IFLE, IFLT, IFNE, IFNONNULL, IFNULL, IINC, ILOAD, IMUL, INEG, INSTANCEOF, INVOKEINTERFACE, INVOKESPECIAL, INVOKESTATIC, INVOKEVIRTUAL, IOR, IREM, IRETURN, ISHL, ISHR, ISTORE, ISUB, IUSHR, IXOR, JSR, L2D, L2F, L2I, LADD, LALOAD, LAND, LASTORE, LCMP, LCONST_0, LCONST_1, LDC, LDIV, LLOAD, LMUL, LNEG, LOOKUPSWITCH, LOR, LREM, LRETURN, LSHL, LSHR, LSTORE, LSUB, LUSHR, LXOR, MONITORENTER, MONITOREXIT, MULTIANEWARRAY, NEW, NEWARRAY, NOP, POP, POP2, PUTFIELD, PUTSTATIC, RET, RETURN, SALOAD, SASTORE, SIPUSH, SWAP, T_BOOLEAN, T_BYTE, T_CHAR, T_DOUBLE, T_FLOAT, T_INT, T_LONG, T_SHORT, TABLESWITCH
    • Constructor Summary

      Constructors 
      Constructor Description
      ClassGeneratorUtil​(Modifiers classModifiers, java.lang.String className, java.lang.String packageName, java.lang.Class superClass, java.lang.Class[] interfaces, Variable[] vars, DelayedEvalBshMethod[] bshmethods, NameSpace classStaticNameSpace, boolean isInterface)  
    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      byte[] generateClass()
      Generate the class bytecode for this class.
      static ClassGeneratorUtil.ConstructorArgs getConstructorArgs​(java.lang.String superClassName, This classStaticThis, java.lang.Object[] consArgs, int index)
      Evaluate the arguments (if any) for the constructor specified by the constructor index.
      static void initInstance​(GeneratedClass instance, java.lang.String className, java.lang.Object[] args)
      Initialize an instance of the class.
      • Methods inherited from class java.lang.Object

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

      • ClassGeneratorUtil

        public ClassGeneratorUtil​(Modifiers classModifiers,
                                  java.lang.String className,
                                  java.lang.String packageName,
                                  java.lang.Class superClass,
                                  java.lang.Class[] interfaces,
                                  Variable[] vars,
                                  DelayedEvalBshMethod[] bshmethods,
                                  NameSpace classStaticNameSpace,
                                  boolean isInterface)
        Parameters:
        packageName - e.g. "com.foo.bar"
    • Method Detail

      • generateClass

        public byte[] generateClass()
        Generate the class bytecode for this class.
      • getConstructorArgs

        public static ClassGeneratorUtil.ConstructorArgs getConstructorArgs​(java.lang.String superClassName,
                                                                            This classStaticThis,
                                                                            java.lang.Object[] consArgs,
                                                                            int index)
        Evaluate the arguments (if any) for the constructor specified by the constructor index. Return the ConstructorArgs object which contains the actual arguments to the alternate constructor and also the index of that constructor for the constructor switch.
        Parameters:
        consArgs - the arguments to the constructor. These are necessary in the evaluation of the alt constructor args. e.g. Foo(a) { super(a); }
        Returns:
        the ConstructorArgs object containing a constructor selector and evaluated arguments for the alternate constructor
      • initInstance

        public static void initInstance​(GeneratedClass instance,
                                        java.lang.String className,
                                        java.lang.Object[] args)
        Initialize an instance of the class. This method is called from the generated class constructor to evaluate the instance initializer and scripted constructor in the instance namespace.