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
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
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final int
index for any variable introduced in a BINDS clauseprivate Binding
static final int
index of $$ variable which is bound to the current helper instanceprivate int
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 variablestatic final int
index of $@ variable which is bound to an array of the invoked method params in an AT INVOKE rulestatic final int
index for any local variable which must be further identified via its nameprivate String
static final int
index of $METHOD variable which is bound to a String identifying the trigger method and signaturestatic final int
index of $* variable which is bound to an array of the trigger method paramsstatic final int
index of $# variable which is bound to the count of number of trigger method paramsstatic final int
index of $! variable which is bound to the current return value on stack in AT RETURN rulestatic final int
index of $@ variable which is bound to the current throwable on stack in AT THROW rulestatic final int
index of $CLASS variable which is bound to a String identifying the package-qualified trigger classstatic final int
index of $METHOD variable which is bound to a String identifying the trigger method and signature -
Constructor Summary
ConstructorsConstructorDescriptionDollarExpression
(Rule rule, Type type, ParseNode token, int index) constructor for param bindings or special bindingsDollarExpression
(Rule rule, Type type, ParseNode token, String name) constructor for local var bindings -
Method Summary
Modifier and TypeMethodDescriptionvoid
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 possiblevoid
bind
(boolean isUpdateable) void
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.interpret
(HelperAdapter helper) evaluate the expression by interpreting the expression treeinterpretAssign
(HelperAdapter helperAdapter, Object value) execute an assignment to the referenced location by interpretation of the expression, using the object passed in this callensure 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
typeCheckAssign
(Type expected) typecheck the expression as an lvalue of an assignment operationvoid
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
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Field Details
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name
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index
private int indexindex 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
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HELPER_IDX
public static final int HELPER_IDXindex of $$ variable which is bound to the current helper instance- See Also:
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BIND_IDX
public static final int BIND_IDXindex for any variable introduced in a BINDS clause- See Also:
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LOCAL_IDX
public static final int LOCAL_IDXindex for any local variable which must be further identified via its name- See Also:
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RETURN_VALUE_IDX
public static final int RETURN_VALUE_IDXindex of $! variable which is bound to the current return value on stack in AT RETURN rule- See Also:
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THROWABLE_VALUE_IDX
public static final int THROWABLE_VALUE_IDXindex of $@ variable which is bound to the current throwable on stack in AT THROW rule- See Also:
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PARAM_COUNT_IDX
public static final int PARAM_COUNT_IDXindex of $# variable which is bound to the count of number of trigger method params- See Also:
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PARAM_ARRAY_IDX
public static final int PARAM_ARRAY_IDXindex of $* variable which is bound to an array of the trigger method params- See Also:
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INVOKE_PARAM_ARRAY_IDX
public static final int INVOKE_PARAM_ARRAY_IDXindex of $@ variable which is bound to an array of the invoked method params in an AT INVOKE rule- See Also:
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TRIGGER_CLASS_IDX
public static final int TRIGGER_CLASS_IDXindex of $CLASS variable which is bound to a String identifying the package-qualified trigger class- See Also:
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TRIGGER_METHOD_IDX
public static final int TRIGGER_METHOD_IDXindex of $METHOD variable which is bound to a String identifying the trigger method and signature- See Also:
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NEW_CLASS_IDX
public static final int NEW_CLASS_IDXindex of $METHOD variable which is bound to a String identifying the trigger method and signature- See Also:
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Constructor Details
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DollarExpression
constructor for param bindings or special bindings- Parameters:
rule
- the rule for this expressiontype
- the type for this expressiontoken
- the token for this expressionindex
- the type of DollarExpression this is
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DollarExpression
constructor for local var bindings- Parameters:
rule
- the rule for this expressiontype
- the type for this expressiontoken
- the token for this expressionname
- the name of the local var referenced by this DollarVariable
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Method Details
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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- Specified by:
bind
in classExpression
- Throws:
TypeException
- if any variable is missing or has the wrong type
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bindAssign
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 classAssignableExpression
- Throws:
TypeException
- if any variable is missing or has the wrong type
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bind
- Throws:
TypeException
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typeCheck
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 classExpression
- 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
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typeCheckAssign
Description copied from class:AssignableExpression
typecheck the expression as an lvalue of an assignment operation- Specified by:
typeCheckAssign
in classAssignableExpression
- Parameters:
expected
- the expected type for the expression- Returns:
- the expression type
- Throws:
TypeException
- if a type check error occurs
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typeCheckAny
private void typeCheckAny() -
interpret
Description copied from class:Expression
evaluate the expression by interpreting the expression tree- Specified by:
interpret
in classExpression
- 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
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compile
public void compile(org.objectweb.asm.MethodVisitor mv, CompileContext compileContext) throws CompileException - Specified by:
compile
in classRuleElement
- Throws:
CompileException
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interpretAssign
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 classAssignableExpression
- 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
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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 classAssignableExpression
- Parameters:
mv
- the current method visitorcompileContext
- the current compile context- Throws:
CompileException
- if a compile error occurs
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writeTo
- Specified by:
writeTo
in classExpression
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