Class DollarExpression
- java.lang.Object
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- org.jboss.byteman.rule.RuleElement
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- org.jboss.byteman.rule.expression.Expression
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- org.jboss.byteman.rule.expression.AssignableExpression
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- org.jboss.byteman.rule.expression.DollarExpression
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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
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Field Summary
Fields Modifier and Type Field Description static int
BIND_IDX
index for any variable introduced in a BINDS clauseprivate Binding
binding
static int
HELPER_IDX
index of $$ variable which is bound to the current helper instanceprivate 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 variablestatic int
INVOKE_PARAM_ARRAY_IDX
index of $@ variable which is bound to an array of the invoked method params in an AT INVOKE rulestatic int
LOCAL_IDX
index for any local variable which must be further identified via its nameprivate java.lang.String
name
static int
NEW_CLASS_IDX
index of $METHOD variable which is bound to a String identifying the trigger method and signaturestatic int
PARAM_ARRAY_IDX
index of $* variable which is bound to an array of the trigger method paramsstatic int
PARAM_COUNT_IDX
index of $# variable which is bound to the count of number of trigger method paramsstatic int
RETURN_VALUE_IDX
index of $! variable which is bound to the current return value on stack in AT RETURN rulestatic int
THROWABLE_VALUE_IDX
index of $@ variable which is bound to the current throwable on stack in AT THROW rulestatic int
TRIGGER_CLASS_IDX
index of $CLASS variable which is bound to a String identifying the package-qualified trigger classstatic int
TRIGGER_METHOD_IDX
index of $METHOD variable which is bound to a String identifying the trigger method and signature
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Constructor Summary
Constructors Constructor Description DollarExpression(Rule rule, Type type, ParseNode token, int index)
constructor for param bindings or special bindingsDollarExpression(Rule rule, Type type, ParseNode token, java.lang.String name)
constructor for local var bindings
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Method Summary
All Methods Instance Methods Concrete Methods 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 possiblevoid
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.java.lang.Object
interpret(HelperAdapter helper)
evaluate the expression by interpreting the expression treejava.lang.Object
interpretAssign(HelperAdapter helperAdapter, java.lang.Object value)
execute an assignment to the referenced location by interpretation of the expression, using the object passed in this callType
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 operationvoid
writeTo(java.io.StringWriter stringWriter)
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Methods inherited from class org.jboss.byteman.rule.expression.Expression
getPos, getType
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Methods inherited from class org.jboss.byteman.rule.RuleElement
getBindings, getTypeGroup, rebox, toString
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Field Detail
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name
private java.lang.String name
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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
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binding
private Binding binding
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HELPER_IDX
public static final int HELPER_IDX
index of $$ variable which is bound to the current helper instance- See Also:
- Constant Field Values
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BIND_IDX
public static final int BIND_IDX
index for any variable introduced in a BINDS clause- See Also:
- Constant Field Values
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LOCAL_IDX
public static final int LOCAL_IDX
index for any local variable which must be further identified via its name- See Also:
- Constant Field Values
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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:
- Constant Field Values
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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:
- Constant Field Values
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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:
- Constant Field Values
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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:
- Constant Field Values
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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:
- Constant Field Values
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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:
- Constant Field Values
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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:
- Constant Field Values
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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:
- Constant Field Values
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Constructor Detail
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DollarExpression
public DollarExpression(Rule rule, Type type, ParseNode token, int index)
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
public DollarExpression(Rule rule, Type type, ParseNode token, java.lang.String name)
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 Detail
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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 classExpression
- Throws:
TypeException
- if any variable is missing or has the wrong type
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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 classAssignableExpression
- Throws:
TypeException
- if any variable is missing or has the wrong type
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bind
public void bind(boolean isUpdateable) throws TypeException
- Throws:
TypeException
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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 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
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 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()
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interpret
public java.lang.Object interpret(HelperAdapter helper) throws ExecuteException
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
public java.lang.Object interpretAssign(HelperAdapter helperAdapter, java.lang.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 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
public void writeTo(java.io.StringWriter stringWriter)
- Specified by:
writeTo
in classExpression
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