Rule Definition
If you have different functionalities, you probably do not want every class of each to be accessible from any other functional areas. This rule makes sure that no restricted classes is accessed from outside its own function area.

Remediation
Keep every functional area loosely coupled.

Violation Code Sample

package functional
{
 import functional.func1.api.Func1ExposedClass;
 import functional.func1.restricted.Func1RestrictedClass; // VIOLATION
 import functional.func2.api.Func2ExposedClass;
 import functional.func2.restricted.Func2RestrictedClass; // VIOLATION
 
 public class FunctionClient
 {
 }
}
package functional.func1.api

{
 import functional.func1.restricted.Func1RestrictedClass; 
 import functional.func2.api.Func2ExposedClass;
 import functional.func2.restricted.Func2RestrictedClass; // VIOLATION
 
 public class Func1ExposedClass
 {
 }
}
package functional.func1.restricted
{
 import functional.func1.api.Func1ExposedClass;
 import functional.func2.api.Func2ExposedClass;
 import functional.func2.restricted.Func2RestrictedClass; // VIOLATION
 
 public class Func1RestrictedClass
 {
 }
}
package functional.func2.api
{
 import functional.func1.api.Func1ExposedClass;
 import functional.func1.restricted.Func1RestrictedClass; // VIOLATION
 import functional.func2.restricted.Func2RestrictedClass;
 
 public class Func2ExposedClass
 {
 }
}
package functional.func2.restricted
{
 import functional.func1.api.Func1ExposedClass;
 import functional.func1.restricted.Func1RestrictedClass; // VIOLATION
 import functional.func2.api.Func2ExposedClass;
 
 public class Func2RestrictedClass
 {
 }
}

http://opensource.adobe.com/wiki/display/flexpmd/FlexPMD