jif.types.principal
Class Principal_c

java.lang.Object
  polyglot.types.TypeObject_c
      jif.types.principal.Principal_c

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, Param, Principal, polyglot.types.TypeObject, polyglot.util.Copy

Direct Known Subclasses:

BottomPrincipal_c, ConjunctivePrincipal_c, DisjunctivePrincipal_c, DynamicPrincipal_c, ExternalPrincipal_c, ParamPrincipal_c, TopPrincipal_c, UnknownPrincipal_c, VarPrincipal_c

public abstract class Principal_c
extends polyglot.types.TypeObject_c
implements Principal

An abstract implementation of the Principal interface.

See Also:

Serialized Form

Field Summary

protected java.util.Set

variables

Fields inherited from class polyglot.types.TypeObject_c

position, ts

Constructor Summary

Principal_c(JifTypeSystem ts, polyglot.util.Position pos)

Principal_c(JifTypeSystem ts, polyglot.util.Position pos, PrincipalToJavaExpr toJava)

Method Summary

abstract boolean	equalsImpl(polyglot.types.TypeObject o)
abstract int	hashCode()
boolean	hasVariables() Does the label contain any variables at all? This includes variables that are in bounds of arg labels.
boolean	isBottomPrincipal()
abstract boolean	isCanonical()
abstract boolean	isRuntimeRepresentable()
boolean	isTopPrincipal()
PathMap	labelCheck(JifContext A, LabelChecker lc) Label check the principal, which will determine how much information may be gained if the principal is evaluated at runtime.
Principal	simplify() Simplify the label, using the actsfor relation if needed
Principal	subst(LabelSubstitution substitution)
java.util.List	throwTypes(polyglot.types.TypeSystem ts) If the principal is runtime representable, when it is evaluated at runtime it may throw exceptions.
polyglot.ast.Expr	toJava(JifToJavaRewriter rw)
java.util.Set	variables() The set of variables that this label contains including variables contained in upper bounds of arg labels.

Methods inherited from class polyglot.types.TypeObject_c

copy, equals, position, typeSystem

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface polyglot.types.TypeObject

position, typeSystem

Methods inherited from interface polyglot.util.Copy

copy

Field Detail

variables

protected java.util.Set variables

Constructor Detail

Principal_c

public Principal_c(JifTypeSystem ts,
                   polyglot.util.Position pos)

Principal_c

public Principal_c(JifTypeSystem ts,
                   polyglot.util.Position pos,
                   PrincipalToJavaExpr toJava)

Method Detail

toJava

public polyglot.ast.Expr toJava(JifToJavaRewriter rw)
                         throws polyglot.types.SemanticException

Specified by:

toJava in interface Principal

Throws:

polyglot.types.SemanticException

hasVariables

public final boolean hasVariables()

Description copied from interface: Principal

Does the label contain any variables at all? This includes variables that are in bounds of arg labels.

Specified by:

hasVariables in interface Principal

isTopPrincipal

public boolean isTopPrincipal()

Specified by:

isTopPrincipal in interface Principal

isBottomPrincipal

public boolean isBottomPrincipal()

Specified by:

isBottomPrincipal in interface Principal

isCanonical

public abstract boolean isCanonical()

Specified by:

isCanonical in interface Param

Specified by:

isCanonical in interface polyglot.types.TypeObject

isRuntimeRepresentable

public abstract boolean isRuntimeRepresentable()

Specified by:

isRuntimeRepresentable in interface Param

equalsImpl

public abstract boolean equalsImpl(polyglot.types.TypeObject o)

Specified by:

equalsImpl in interface polyglot.types.TypeObject

Overrides:

equalsImpl in class polyglot.types.TypeObject_c

hashCode

public abstract int hashCode()

Overrides:

hashCode in class polyglot.types.TypeObject_c

throwTypes

public java.util.List throwTypes(polyglot.types.TypeSystem ts)

Description copied from interface: Principal

If the principal is runtime representable, when it is evaluated at runtime it may throw exceptions. This method returns a list of the exceptions that the runtime evaluation of the principal may produce. If the principal cannot be evaluated at runtime, an empty list should be returned.

Specified by:

throwTypes in interface Principal

subst

public Principal subst(LabelSubstitution substitution)
                throws polyglot.types.SemanticException

Specified by:

subst in interface Principal

Parameters:

substitution - The LabelSubstitution to apply to this principal

Returns:

the result of applying labelSubst to this principal.

Throws:

polyglot.types.SemanticException

labelCheck

public PathMap labelCheck(JifContext A,
                          LabelChecker lc)

Description copied from interface: Principal

Label check the principal, which will determine how much information may be gained if the principal is evaluated at runtime. For example, given the dynamic principal p, where p is a local variable, evaluation of this label at runtime will reveal as much information as the label of p. For example, the following code is illegal, as the runtime evaluation of the principal reveals too much information

 boolean{Alice:} secret = ...;
 final principal{Alice:} p = secret?Bob:Chuck;
 boolean{} leak = false;
 if (p actsfor Bob) { // evaluation of p reveals
                      // information at level {Alice:}
     leak = true;
        } 
 

Specified by:

labelCheck in interface Principal

See Also:

Jif.labelCheck(LabelChecker), Label.labelCheck(JifContext, LabelChecker)

variables

public java.util.Set variables()

Description copied from interface: Principal

The set of variables that this label contains including variables contained in upper bounds of arg labels.

Specified by:

variables in interface Principal

simplify

public Principal simplify()

Description copied from interface: Principal

Simplify the label, using the actsfor relation if needed

Specified by:

simplify in interface Principal