net.mtu.eggplant.dbc
Class AssertTools

java.lang.Object
  net.mtu.eggplant.dbc.AssertTools

public final class AssertTools

extends Object

class of static helper methods for assertions.

Version:

$Revision: 1.9 $

Nested Class Summary

static class

AssertTools.MethodLock Used for locking methods.

Field Summary

static String	ASSERT_BEHAVIOR what to do if an assertion violation is raised
static boolean	ENFORCE_ASSERT_CONDITION if assert conditions should be enforced
static boolean	ENFORCE_INHERITED_CONDITIONS if inherited conditions should be enforced
static boolean	ENFORCE_INVARIANT_CONDITION if invariant conditions should be enforced
static boolean	ENFORCE_POST_CONDITION if post conditions should be enforced
static boolean	ENFORCE_PRE_CONDITION if pre conditions should be enforced
static net.mtu.eggplant.dbc.AssertTools.NONE	NO_CLASS Used to represent no class.
static Method	NO_METHOD Used in caching to represent that no super method can be found.

Method Summary

static void	assertFailed(AssertionViolation av) Called when an assert fails.
static Class	classForName(String className) Get the class object for this class name.
static boolean	extendsObject(AssertClass clazz)
static void	fail(AssertionViolation av) Called to signal an assertion failure.
static Class[]	findAssertClassInterfaces(Class[] interfaces) Do a depth first search of each interface heirarchy and return the class objects that implement the DBC conditions, if found.
static Method	findSuperMethod(Class thisClass, String methodName, Class[] methodArgs) Find the superclasses method, this is my version of a superClass method, this means that the method name is ____methodName where packageName is the package the class is in with the characters '.'
static AssertionViolation	getCurrentAssertionViolation()
static void	internalError(String message) called whenever an erorr occurs in the code that was generated that is not caused by the user.
static void	invariantFailed(AssertionViolation av) called when an invariant fails.
static boolean	isPrimative(String type)
static AssertTools.MethodLock	lockMethod(String signature, Object instance) Lock a method.
static void	postConditionFailed(AssertionViolation av) called when a post condition fails.
static void	preConditionFailed(AssertionViolation av) Called when a precondition fails.
static void	setCurrentAssertionViolation(AssertionViolation violation) set the assertion violation that should be throw next.
static void	setUniqueParams(AssertClass assertClass) Calculate the unique parameters for all constructors for class and set those values on the AssertMethod objects.
static boolean	unlockMethod(AssertTools.MethodLock lock) Unlock a method.

Methods inherited from class java.lang.Object

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

Field Detail

ENFORCE_INHERITED_CONDITIONS

public static final boolean ENFORCE_INHERITED_CONDITIONS

if inherited conditions should be enforced

See Also:

net.mtu.eggplant.dbc

ENFORCE_ASSERT_CONDITION

public static final boolean ENFORCE_ASSERT_CONDITION

if assert conditions should be enforced

See Also:

net.mtu.eggplant.dbc

ENFORCE_INVARIANT_CONDITION

public static final boolean ENFORCE_INVARIANT_CONDITION

if invariant conditions should be enforced

See Also:

net.mtu.eggplant.dbc

ENFORCE_PRE_CONDITION

public static final boolean ENFORCE_PRE_CONDITION

if pre conditions should be enforced

See Also:

net.mtu.eggplant.dbc

ENFORCE_POST_CONDITION

public static final boolean ENFORCE_POST_CONDITION

if post conditions should be enforced

See Also:

net.mtu.eggplant.dbc

ASSERT_BEHAVIOR

public static final String ASSERT_BEHAVIOR

what to do if an assertion violation is raised

See Also:

net.mtu.eggplant.dbc

NO_CLASS

public static final net.mtu.eggplant.dbc.AssertTools.NONE NO_CLASS

Used to represent no class. This is used for caching. If this class is encountered it, then one can be assured that it's already been determined that a class has been checked for and not found.

NO_METHOD

public static final Method NO_METHOD

Used in caching to represent that no super method can be found.

Method Detail

findAssertClassInterfaces

public static Class[] findAssertClassInterfaces(Class[] interfaces)

Do a depth first search of each interface heirarchy and return the class objects that implement the DBC conditions, if found.

Parameters:

interfaces - the interfaces to look in

Returns:

the DBC classes, may be an empty array if no DBC classes can be found

PreConditions

(null != interfaces)

PostConditions

(null != $return)

findSuperMethod

public static Method findSuperMethod(Class thisClass,
                                     String methodName,
                                     Class[] methodArgs)

Find the superclasses method, this is my version of a superClass method, this means that the method name is ____methodName where packageName is the package the class is in with the characters '.' and '$' replaced with '_' and className is the name of the class.

Returns:

the method found, if no such method can be found null is returned

PreConditions

(thisClass != null), (methodName != null), (methodArgs != null)

setCurrentAssertionViolation

public static void setCurrentAssertionViolation(AssertionViolation violation)

set the assertion violation that should be throw next.

getCurrentAssertionViolation

public static AssertionViolation getCurrentAssertionViolation()

assertFailed

public static void assertFailed(AssertionViolation av)

Called when an assert fails.

Parameters:

av - AssertionViolation with information about the failure

See Also:

ENFORCE_ASSERT_CONDITION

PreConditions

(av != null)

invariantFailed

public static void invariantFailed(AssertionViolation av)

called when an invariant fails.

Parameters:

av - AssertionViolation with information about the failure

See Also:

ENFORCE_INVARIANT_CONDITION

PreConditions

(av != null)

postConditionFailed

public static void postConditionFailed(AssertionViolation av)

called when a post condition fails.

Parameters:

av - AssertionViolation with information about the failure

See Also:

ENFORCE_POST_CONDITION

PreConditions

(av != null)

preConditionFailed

public static void preConditionFailed(AssertionViolation av)

Called when a precondition fails.

Parameters:

av - AssertionViolation with information about the failure

See Also:

ENFORCE_PRE_CONDITION

PreConditions

(av != null)

fail

public static void fail(AssertionViolation av)

Called to signal an assertion failure.

See Also:

ASSERT_BEHAVIOR

PreConditions

(null != av)

internalError

public static void internalError(String message)

called whenever an erorr occurs in the code that was generated that is not caused by the user. Generate some useful message and then blow up.

classForName

public static Class classForName(String className)

Get the class object for this class name. Just like Class.forName(), but returns null on an exception.

Returns:

null for no such class found

lockMethod

public static AssertTools.MethodLock lockMethod(String signature,
                                                Object instance)

Lock a method. This is used at the top of the pre, post and invariant check methods so that the methods don't get called recursively.

Parameters:

signature - the signature of the method to lock

instance - the instance that should be locked. this or null (for static methods)

Returns:

the lock if it succeeded, null if it failed

unlockMethod

public static boolean unlockMethod(AssertTools.MethodLock lock)

Unlock a method.

Parameters:

lock - the lock that was recieved from lockMethod()

Returns:

true if the method was locked

See Also:

lockMethod(String, Object)

setUniqueParams

public static void setUniqueParams(AssertClass assertClass)

Calculate the unique parameters for all constructors for class and set those values on the AssertMethod objects. This is for creating a unique parameter list for checking preconditions on constructors. If in a class there exists a constructor C1 such that there is another constructor C2 that has number parameters N+1, where N is the number of parameters to C1, and the first N parameter types match exactly and the N+1 parameter is not a primative there is a possibility for ambiguity errors with the generated constructors. So boolean parameters are added to such constructors to guarentee uniqueness.

Here is an example:

 This won't work:
 public class A {
   public A(int i) {
     this(i, new AssertDummy(i));
   }
   private A(int i, AssertDummy ad) {
     //generated to handle preconditions
   }
 
   public A(int i, int j) {
    this(i, null);
    //should call following constructor, but with generated constructor is ambiguous
   }
   
   public A(int i, Component c) {
     //do something
   }
 }
 This will work:
 public class A {
   public A(int i) {
     this(i, true, new AssertDummy(i));
   }
   private A(int i, boolean dummy0, AssertDummy ad) {
     //generated to handle preconditions
   }
 
   public A(int i, int j) {
    this(i, null);
    //should call following constructor, and now will since the code is no longer ambigous
   }
   
   public A(int i, Component c) {
     //do something
   }
 }
 

PreConditions

(assertClass != null)

isPrimative

public static boolean isPrimative(String type)

Parameters:

type - String that represents a java type

Returns:

true if type represents a java primative

PreConditions

(type != null)

extendsObject

public static boolean extendsObject(AssertClass clazz)

Returns:

true if clazz extends Object and has no implemented interfaces. This signals a case where optimizations can be done by not generated assertion methods.