Class AdviceAdapter

  • All Implemented Interfaces:
    Opcodes

    public abstract class AdviceAdapter
    extends GeneratorAdapter
    implements Opcodes
    A MethodVisitor to insert before, after and around advices in methods and constructors. For constructors, the code keeps track of the elements on the stack in order to detect when the super class constructor is called (note that there can be multiple such calls in different branches). onMethodEnter is called after each super class constructor call, because the object cannot be used before it is properly initialized.
    • Field Detail

      • methodAccess

        protected int methodAccess
        The access flags of the visited method.
      • methodDesc

        protected java.lang.String methodDesc
        The descriptor of the visited method.
    • Constructor Detail

      • AdviceAdapter

        protected AdviceAdapter​(int api,
                                MethodVisitor methodVisitor,
                                int access,
                                java.lang.String name,
                                java.lang.String descriptor)
        Constructs a new AdviceAdapter.
        Parameters:
        api - the ASM API version implemented by this visitor. Must be one of Opcodes.ASM4, Opcodes.ASM5, Opcodes.ASM6 or Opcodes.ASM7.
        methodVisitor - the method visitor to which this adapter delegates calls.
        access - the method's access flags (see Opcodes).
        name - the method's name.
        descriptor - the method's descriptor (see Type).
    • Method Detail

      • visitCode

        public void visitCode()
        Description copied from class: MethodVisitor
        Starts the visit of the method's code, if any (i.e. non abstract method).
        Overrides:
        visitCode in class MethodVisitor
      • visitLabel

        public void visitLabel​(Label label)
        Description copied from class: MethodVisitor
        Visits a label. A label designates the instruction that will be visited just after it.
        Overrides:
        visitLabel in class MethodVisitor
        Parameters:
        label - a Label object.
      • visitInsn

        public void visitInsn​(int opcode)
        Description copied from class: MethodVisitor
        Visits a zero operand instruction.
        Overrides:
        visitInsn in class MethodVisitor
        Parameters:
        opcode - the opcode of the instruction to be visited. This opcode is either NOP, ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, LCONST_0, LCONST_1, FCONST_0, FCONST_1, FCONST_2, DCONST_0, DCONST_1, IALOAD, LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD, IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE, SASTORE, POP, POP2, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP, IADD, LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB, IMUL, LMUL, FMUL, DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM, FREM, DREM, INEG, LNEG, FNEG, DNEG, ISHL, LSHL, ISHR, LSHR, IUSHR, LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, I2L, I2F, I2D, L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F, I2B, I2C, I2S, LCMP, FCMPL, FCMPG, DCMPL, DCMPG, IRETURN, LRETURN, FRETURN, DRETURN, ARETURN, RETURN, ARRAYLENGTH, ATHROW, MONITORENTER, or MONITOREXIT.
      • visitVarInsn

        public void visitVarInsn​(int opcode,
                                 int var)
        Description copied from class: MethodVisitor
        Visits a local variable instruction. A local variable instruction is an instruction that loads or stores the value of a local variable.
        Overrides:
        visitVarInsn in class LocalVariablesSorter
        Parameters:
        opcode - the opcode of the local variable instruction to be visited. This opcode is either ILOAD, LLOAD, FLOAD, DLOAD, ALOAD, ISTORE, LSTORE, FSTORE, DSTORE, ASTORE or RET.
        var - the operand of the instruction to be visited. This operand is the index of a local variable.
      • visitFieldInsn

        public void visitFieldInsn​(int opcode,
                                   java.lang.String owner,
                                   java.lang.String name,
                                   java.lang.String descriptor)
        Description copied from class: MethodVisitor
        Visits a field instruction. A field instruction is an instruction that loads or stores the value of a field of an object.
        Overrides:
        visitFieldInsn in class MethodVisitor
        Parameters:
        opcode - the opcode of the type instruction to be visited. This opcode is either GETSTATIC, PUTSTATIC, GETFIELD or PUTFIELD.
        owner - the internal name of the field's owner class (see Type.getInternalName()).
        name - the field's name.
        descriptor - the field's descriptor (see Type).
      • visitLdcInsn

        public void visitLdcInsn​(java.lang.Object value)
        Description copied from class: MethodVisitor
        Visits a LDC instruction. Note that new constant types may be added in future versions of the Java Virtual Machine. To easily detect new constant types, implementations of this method should check for unexpected constant types, like this:
         if (cst instanceof Integer) {
             // ...
         } else if (cst instanceof Float) {
             // ...
         } else if (cst instanceof Long) {
             // ...
         } else if (cst instanceof Double) {
             // ...
         } else if (cst instanceof String) {
             // ...
         } else if (cst instanceof Type) {
             int sort = ((Type) cst).getSort();
             if (sort == Type.OBJECT) {
                 // ...
             } else if (sort == Type.ARRAY) {
                 // ...
             } else if (sort == Type.METHOD) {
                 // ...
             } else {
                 // throw an exception
             }
         } else if (cst instanceof Handle) {
             // ...
         } else if (cst instanceof ConstantDynamic) {
             // ...
         } else {
             // throw an exception
         }
         
        Overrides:
        visitLdcInsn in class MethodVisitor
        Parameters:
        value - the constant to be loaded on the stack. This parameter must be a non null Integer, a Float, a Long, a Double, a String, a Type of OBJECT or ARRAY sort for .class constants, for classes whose version is 49, a Type of METHOD sort for MethodType, a Handle for MethodHandle constants, for classes whose version is 51 or a ConstantDynamic for a constant dynamic for classes whose version is 55.
      • visitMultiANewArrayInsn

        public void visitMultiANewArrayInsn​(java.lang.String descriptor,
                                            int numDimensions)
        Description copied from class: MethodVisitor
        Visits a MULTIANEWARRAY instruction.
        Overrides:
        visitMultiANewArrayInsn in class MethodVisitor
        Parameters:
        descriptor - an array type descriptor (see Type).
        numDimensions - the number of dimensions of the array to allocate.
      • visitTypeInsn

        public void visitTypeInsn​(int opcode,
                                  java.lang.String type)
        Description copied from class: MethodVisitor
        Visits a type instruction. A type instruction is an instruction that takes the internal name of a class as parameter.
        Overrides:
        visitTypeInsn in class MethodVisitor
        Parameters:
        opcode - the opcode of the type instruction to be visited. This opcode is either NEW, ANEWARRAY, CHECKCAST or INSTANCEOF.
        type - the operand of the instruction to be visited. This operand must be the internal name of an object or array class (see Type.getInternalName()).
      • visitMethodInsn

        public void visitMethodInsn​(int opcodeAndSource,
                                    java.lang.String owner,
                                    java.lang.String name,
                                    java.lang.String descriptor,
                                    boolean isInterface)
        Description copied from class: MethodVisitor
        Visits a method instruction. A method instruction is an instruction that invokes a method.
        Overrides:
        visitMethodInsn in class MethodVisitor
        Parameters:
        opcodeAndSource - the opcode of the type instruction to be visited. This opcode is either INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC or INVOKEINTERFACE.
        owner - the internal name of the method's owner class (see Type.getInternalName()).
        name - the method's name.
        descriptor - the method's descriptor (see Type).
        isInterface - if the method's owner class is an interface.
      • visitInvokeDynamicInsn

        public void visitInvokeDynamicInsn​(java.lang.String name,
                                           java.lang.String descriptor,
                                           Handle bootstrapMethodHandle,
                                           java.lang.Object... bootstrapMethodArguments)
        Description copied from class: MethodVisitor
        Visits an invokedynamic instruction.
        Overrides:
        visitInvokeDynamicInsn in class MethodVisitor
        Parameters:
        name - the method's name.
        descriptor - the method's descriptor (see Type).
        bootstrapMethodHandle - the bootstrap method.
        bootstrapMethodArguments - the bootstrap method constant arguments. Each argument must be an Integer, Float, Long, Double, String, Type, Handle or ConstantDynamic value. This method is allowed to modify the content of the array so a caller should expect that this array may change.
      • visitJumpInsn

        public void visitJumpInsn​(int opcode,
                                  Label label)
        Description copied from class: MethodVisitor
        Visits a jump instruction. A jump instruction is an instruction that may jump to another instruction.
        Overrides:
        visitJumpInsn in class MethodVisitor
        Parameters:
        opcode - the opcode of the type instruction to be visited. This opcode is either IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ, IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ACMPEQ, IF_ACMPNE, GOTO, JSR, IFNULL or IFNONNULL.
        label - the operand of the instruction to be visited. This operand is a label that designates the instruction to which the jump instruction may jump.
      • visitLookupSwitchInsn

        public void visitLookupSwitchInsn​(Label dflt,
                                          int[] keys,
                                          Label[] labels)
        Description copied from class: MethodVisitor
        Visits a LOOKUPSWITCH instruction.
        Overrides:
        visitLookupSwitchInsn in class MethodVisitor
        Parameters:
        dflt - beginning of the default handler block.
        keys - the values of the keys.
        labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the keys[i] key.
      • visitTableSwitchInsn

        public void visitTableSwitchInsn​(int min,
                                         int max,
                                         Label dflt,
                                         Label... labels)
        Description copied from class: MethodVisitor
        Visits a TABLESWITCH instruction.
        Overrides:
        visitTableSwitchInsn in class MethodVisitor
        Parameters:
        min - the minimum key value.
        max - the maximum key value.
        dflt - beginning of the default handler block.
        labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the min + i key.
      • visitTryCatchBlock

        public void visitTryCatchBlock​(Label start,
                                       Label end,
                                       Label handler,
                                       java.lang.String type)
        Description copied from class: MethodVisitor
        Visits a try catch block.
        Overrides:
        visitTryCatchBlock in class MethodVisitor
        Parameters:
        start - the beginning of the exception handler's scope (inclusive).
        end - the end of the exception handler's scope (exclusive).
        handler - the beginning of the exception handler's code.
        type - the internal name of the type of exceptions handled by the handler, or null to catch any exceptions (for "finally" blocks).
      • onMethodEnter

        protected void onMethodEnter()
        Generates the "before" advice for the visited method. The default implementation of this method does nothing. Subclasses can use or change all the local variables, but should not change state of the stack. This method is called at the beginning of the method or after super class constructor has been called (in constructors).
      • onMethodExit

        protected void onMethodExit​(int opcode)
        Generates the "after" advice for the visited method. The default implementation of this method does nothing. Subclasses can use or change all the local variables, but should not change state of the stack. This method is called at the end of the method, just before return and athrow instructions. The top element on the stack contains the return value or the exception instance. For example:
         public void onMethodExit(final int opcode) {
           if (opcode == RETURN) {
             visitInsn(ACONST_NULL);
           } else if (opcode == ARETURN || opcode == ATHROW) {
             dup();
           } else {
             if (opcode == LRETURN || opcode == DRETURN) {
               dup2();
             } else {
               dup();
             }
             box(Type.getReturnType(this.methodDesc));
           }
           visitIntInsn(SIPUSH, opcode);
           visitMethodInsn(INVOKESTATIC, owner, "onExit", "(Ljava/lang/Object;I)V");
         }
        
         // An actual call back method.
         public static void onExit(final Object exitValue, final int opcode) {
           ...
         }
         
        Parameters:
        opcode - one of Opcodes.RETURN, Opcodes.IRETURN, Opcodes.FRETURN, Opcodes.ARETURN, Opcodes.LRETURN, Opcodes.DRETURN or Opcodes.ATHROW.