Package org.jboss.byteman.rule.expression

Class DollarExpression

java.lang.Object
org.jboss.byteman.rule.RuleElement
org.jboss.byteman.rule.expression.Expression
org.jboss.byteman.rule.expression.AssignableExpression
org.jboss.byteman.rule.expression.DollarExpression
public class DollarExpression extends AssignableExpression
an expression which refers either to a builtin variable or to a bound parameter of the triggering method for an ECA rule. builtin variables are written as a dollar sign followed by a leading alpha-underscore, trailing alpha-numeric-underscore string. bound parameters are written as a dollar sign followed by a non-negativeinteger parameter index e.g. if the rule applies to method foo.bar(int baz, Mumble mumble) then an occurrence of $2 appearing as an expression in a rule would have type Mumble and evaluate to the value of mumble at the point when the rule was triggered. At present there are no special variables but we may need to add some later

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    BIND_IDX
    index for any variable introduced in a BINDS clause
    private Binding
    binding
     
    static final int
    HELPER_IDX
    index of $$ variable which is bound to the current helper instance
    private int
    index
    index is positive or zero if this is a reference to a method param and negative if this is a reference to the current helper, the return value on the stack in an AT EXIT rule or a local or BIND variable
    static final int
    INVOKE_PARAM_ARRAY_IDX
    index of $@ variable which is bound to an array of the invoked method params in an AT INVOKE rule
    static final int
    LOCAL_IDX
    index for any local variable which must be further identified via its name
    private String
    name
     
    static final int
    NEW_CLASS_IDX
    index of $METHOD variable which is bound to a String identifying the trigger method and signature
    static final int
    PARAM_ARRAY_IDX
    index of $* variable which is bound to an array of the trigger method params
    static final int
    PARAM_COUNT_IDX
    index of $# variable which is bound to the count of number of trigger method params
    static final int
    RETURN_VALUE_IDX
    index of $! variable which is bound to the current return value on stack in AT RETURN rule
    static final int
    THROWABLE_VALUE_IDX
    index of $@ variable which is bound to the current throwable on stack in AT THROW rule
    static final int
    TRIGGER_CLASS_IDX
    index of $CLASS variable which is bound to a String identifying the package-qualified trigger class
    static final int
    TRIGGER_METHOD_IDX
    index of $METHOD variable which is bound to a String identifying the trigger method and signature

    Fields inherited from class org.jboss.byteman.rule.expression.Expression

    charPos, line, rule, token, type

  • Constructor Summary

    Constructors
    Constructor
    Description
    DollarExpression(Rule rule, Type type, ParseNode token, int index)
    constructor for param bindings or special bindings
    DollarExpression(Rule rule, Type type, ParseNode token, String name)
    constructor for local var bindings

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    bind()
    verify that variables mentioned in this expression are actually available in the supplied bindings list and infer/validate the type of this expression or its subexpressions where possible
    void
    bind(boolean isUpdateable)
     
    void
    bindAssign()
    verify that variables mentioned in this expression are actually available in the supplied bindings list.
    void
    compile(org.objectweb.asm.MethodVisitor mv, CompileContext compileContext)
     
    void
    compileAssign(org.objectweb.asm.MethodVisitor mv, CompileContext compileContext)
    compile an assignment to the referenced location using the value on the top of the Java stack.
    Object
    interpret(HelperAdapter helper)
    evaluate the expression by interpreting the expression tree
    Object
    interpretAssign(HelperAdapter helperAdapter, Object value)
    execute an assignment to the referenced location by interpretation of the expression, using the object passed in this call
    Type
    typeCheck(Type expected)
    ensure that all type references in the expression and its component expressions can be resolved, that the type of the expression is well-defined and that it is compatible with the type expected in the context in which it occurs.
    private void
    typeCheckAny()
     
    Type
    typeCheckAssign(Type expected)
    typecheck the expression as an lvalue of an assignment operation
    void
    writeTo(StringWriter stringWriter)
     

    Methods inherited from class org.jboss.byteman.rule.expression.Expression

    getPos, getType

    Methods inherited from class org.jboss.byteman.rule.RuleElement

    getBindings, getTypeGroup, rebox, toString

    Methods inherited from class java.lang.Object

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

  • Field Details

    • name

      private String name

    • index

      private int index
      index is positive or zero if this is a reference to a method param and negative if this is a reference to the current helper, the return value on the stack in an AT EXIT rule or a local or BIND variable

    • binding

      private Binding binding

    • HELPER_IDX

      public static final int HELPER_IDX
      index of $$ variable which is bound to the current helper instance
      See Also:

    • BIND_IDX

      public static final int BIND_IDX
      index for any variable introduced in a BINDS clause
      See Also:

    • LOCAL_IDX

      public static final int LOCAL_IDX
      index for any local variable which must be further identified via its name
      See Also:

    • RETURN_VALUE_IDX

      public static final int RETURN_VALUE_IDX
      index of $! variable which is bound to the current return value on stack in AT RETURN rule
      See Also:

    • THROWABLE_VALUE_IDX

      public static final int THROWABLE_VALUE_IDX
      index of $@ variable which is bound to the current throwable on stack in AT THROW rule
      See Also:

    • PARAM_COUNT_IDX

      public static final int PARAM_COUNT_IDX
      index of $# variable which is bound to the count of number of trigger method params
      See Also:

    • PARAM_ARRAY_IDX

      public static final int PARAM_ARRAY_IDX
      index of $* variable which is bound to an array of the trigger method params
      See Also:

    • INVOKE_PARAM_ARRAY_IDX

      public static final int INVOKE_PARAM_ARRAY_IDX
      index of $@ variable which is bound to an array of the invoked method params in an AT INVOKE rule
      See Also:

    • TRIGGER_CLASS_IDX

      public static final int TRIGGER_CLASS_IDX
      index of $CLASS variable which is bound to a String identifying the package-qualified trigger class
      See Also:

    • TRIGGER_METHOD_IDX

      public static final int TRIGGER_METHOD_IDX
      index of $METHOD variable which is bound to a String identifying the trigger method and signature
      See Also:

    • NEW_CLASS_IDX

      public static final int NEW_CLASS_IDX
      index of $METHOD variable which is bound to a String identifying the trigger method and signature
      See Also:

  • Constructor Details

    • DollarExpression

      public DollarExpression(Rule rule, Type type, ParseNode token, int index)
      constructor for param bindings or special bindings
      Parameters:
      rule - the rule for this expression
      type - the type for this expression
      token - the token for this expression
      index - the type of DollarExpression this is

    • DollarExpression

      public DollarExpression(Rule rule, Type type, ParseNode token, String name)
      constructor for local var bindings
      Parameters:
      rule - the rule for this expression
      type - the type for this expression
      token - the token for this expression
      name - the name of the local var referenced by this DollarVariable

  • Method Details

    • bind

      public void bind() throws TypeException
      verify that variables mentioned in this expression are actually available in the supplied bindings list and infer/validate the type of this expression or its subexpressions where possible
      Specified by:
      bind in class Expression
      Throws:
      TypeException - if any variable is missing or has the wrong type

    • bindAssign

      public void bindAssign() throws TypeException
      verify that variables mentioned in this expression are actually available in the supplied bindings list. infer/validate the type of this expression or its subexpressions where possible
      Specified by:
      bindAssign in class AssignableExpression
      Throws:
      TypeException - if any variable is missing or has the wrong type

    • bind

      public void bind(boolean isUpdateable) throws TypeException
      Throws:
      TypeException

    • typeCheck

      public Type typeCheck(Type expected) throws TypeException
      Description copied from class: Expression
      ensure that all type references in the expression and its component expressions can be resolved, that the type of the expression is well-defined and that it is compatible with the type expected in the context in which it occurs.
      Specified by:
      typeCheck in class Expression
      Parameters:
      expected - the type expected for the expression in the contxet in which it occurs. this may be void but should not be undefined at the point where type checking is performed.
      Returns:
      the type of the expression
      Throws:
      TypeException - if a type check failure occurs

    • typeCheckAssign

      public Type typeCheckAssign(Type expected) throws TypeException
      Description copied from class: AssignableExpression
      typecheck the expression as an lvalue of an assignment operation
      Specified by:
      typeCheckAssign in class AssignableExpression
      Parameters:
      expected - the expected type for the expression
      Returns:
      the expression type
      Throws:
      TypeException - if a type check error occurs

    • typeCheckAny

      private void typeCheckAny()

    • interpret

      public Object interpret(HelperAdapter helper) throws ExecuteException
      Description copied from class: Expression
      evaluate the expression by interpreting the expression tree
      Specified by:
      interpret in class Expression
      Parameters:
      helper - an execution context associated with the rule which contains a map of current bindings for rule variables and another map of their declared types both of which are indexed by variable name. This includes entries for the helper (name "-1"), the recipient if the trigger method is not static (name "0") and the trigger method arguments (names "1", ...)
      Returns:
      the result of evaluation as an Object
      Throws:
      ExecuteException - if an error occurs during execution

    • compile

      public void compile(org.objectweb.asm.MethodVisitor mv, CompileContext compileContext) throws CompileException
      Specified by:
      compile in class RuleElement
      Throws:
      CompileException

    • interpretAssign

      public Object interpretAssign(HelperAdapter helperAdapter, Object value) throws ExecuteException
      Description copied from class: AssignableExpression
      execute an assignment to the referenced location by interpretation of the expression, using the object passed in this call
      Specified by:
      interpretAssign in class AssignableExpression
      Parameters:
      helperAdapter - an execution context associated with the rule which contains a map of current bindings for rule variables and another map of their declared types both of which are indexed by variable name. This includes entries for the helper (name "-1"), the recipient if the trigger method is not static (name "0") and the trigger method arguments (names "1", ...)
      value - the value to be assigned to this object
      Returns:
      the result of evaluation as an Object
      Throws:
      ExecuteException - if an error occurs during execution

    • compileAssign

      public void compileAssign(org.objectweb.asm.MethodVisitor mv, CompileContext compileContext) throws CompileException
      Description copied from class: AssignableExpression
      compile an assignment to the referenced location using the value on the top of the Java stack.
      Specified by:
      compileAssign in class AssignableExpression
      Parameters:
      mv - the current method visitor
      compileContext - the current compile context
      Throws:
      CompileException - if a compile error occurs

    • writeTo

      public void writeTo(StringWriter stringWriter)
      Specified by:
      writeTo in class Expression