Hi Jia,
isEqualTo() is used by DoubleToken and ComplexToken to
compare two tokens with an epsilon factor.
Token.isEqualTo() says:
/** Test that the value of this Token is close to the argument
* Token. In this base class, we call isEqualTo(). This method
* should be overridden in derived classes such as DoubleToken
* and ComplexToken to provide type specific actions for
* equality testing using an epsilon factor.
*
* @see #isEqualTo
* @param token The token to test closeness of this token with.
* @return a boolean token that contains the value true if the
* value and units of this token are close to those of the
* argument token.
* If either this token or the argument token is a nil token, then
* a boolean token that contains the value false is returned.
* @exception IllegalActionException If the argument token is not
* of a type that can be compared with this token.
*/
public final BooleanToken isCloseTo(Token token)
throws IllegalActionException {
return isCloseTo(token, ptolemy.math.Complex.EPSILON);
}
It looks like gr SceneGraphToken, gr Scene2DToken and ActorToken
all look like:
public BooleanToken isEqualTo(Token token) throws IllegalActionException {
if (token instanceof ActorToken) {
return new BooleanToken(this == token);
} else {
throw new IllegalActionException(
"Equality test not supported between "
+ this.getClass().getName() + " and "
+ token.getClass().getName() + ".");
}
}
In theory, isEqualTo could call equals(), but I think they are fine
as is.
So, I think we are all set here.
_Christopher
--------
Hi Christopher,
I checked through that list. I do have a questions:
First, for classes like these:
ptolemy/domains/gr/kernel/SceneGraphToken.java
ptolemy/domains/gr/kernel/Scene2DToken.java
ptolemy/data/ActorToken.java
Each has a isEqualTo method (Not sure why we are not overwriting the equals
method), but each also has a type class corresponding to the token, and the
equals method in that type only uses ==. I'm not sure how that works?
Thanks,
Jia
On Tue, Jul 8, 2008 at 4:30 PM, Jia Zou <[EMAIL PROTECTED]> wrote:
> Hi Christopher,
> Thanks for pointing that out. I'll check the rest of the types soon.
>
> Jia
>
>
> On Tue, Jul 8, 2008 at 3:37 PM, Christopher Brooks <[EMAIL PROTECTED]
>
> wrote:
>
>> Hi Jia,
>>
>> Actually, the Javadoc for java.lang.Comparable says that java.
>> "Note that null is not an instance of any class, and e.compareTo(null)
>> should throw a NullPointerException even though e.equals(null)
>> returns false."
>>
>> So, equals(null) should return false and compareTo(null) should throw
>> an NPE.
>>
>> See
>> http://java.sun.com/javase/6/docs/api/java/lang/Comparable.html
>> for details about natural ordering
>>
>>
>> There were no unit tests for ptolemy.actor.util.Time.
>>
>> I created a unit test for this bug and fixed Time.java.
>>
>> One way around this is to do an instanceof check because null is not
>> an instance of a class. So, you'll see equals implemented like:
>>
>> public boolean equals(Object time) {
>> if (time instanceof Time) {
>> return this.compareTo(time) == 0;
>> }
>> return false;
>> }
>>
>> In Ptolemy, the classes have equals() methods. I checked the classes
>> upto DEEvent, could you take a look at the classes below DEEvent?
>>
>> doc/tutorial/LeftRightDirector.java
>> com/JLex/Main.java
>> com/jgoodies/forms/layout/ConstantSize.java
>> com/jgoodies/forms/layout/BoundedSize.java
>> ptolemy/kernel/attributes/VersionAttribute.java
>> ptolemy/backtrack/eclipse/ast/Type.java
>>
>> # No need to check these, they are used for back tracking
>> ptolemy/backtrack/util/java/util/AbstractList.java
>> ptolemy/backtrack/util/java/util/AbstractMap.java
>> ptolemy/backtrack/util/java/util/Collections.java
>> ptolemy/backtrack/util/java/util/Collections.java
>> ptolemy/backtrack/util/java/util/Collections.java
>> ptolemy/backtrack/util/java/util/Collections.java
>> ptolemy/backtrack/util/java/util/Collections.java
>> ptolemy/backtrack/util/java/util/Collections.java
>> ptolemy/backtrack/util/java/util/Collections.java
>> ptolemy/backtrack/util/java/util/Collections.java
>> ptolemy/backtrack/util/java/util/Collections.java
>> ptolemy/backtrack/util/java/util/Collections.java
>> ptolemy/backtrack/util/java/util/Collections.java
>> ptolemy/backtrack/util/java/util/AbstractSet.java
>> ptolemy/backtrack/util/java/util/WeakHashMap.java
>> ptolemy/backtrack/util/java/util/WeakHashMap.java
>> ptolemy/backtrack/util/java/util/Hashtable.java
>>
>> # I checked these
>> ptolemy/math/FixPoint.java
>> ptolemy/math/Overflow.java
>> ptolemy/math/Fraction.java
>> ptolemy/math/FixPointQuantization.java
>> ptolemy/math/Quantization.java
>> ptolemy/math/Precision.java
>> ptolemy/math/Rounding.java
>> ptolemy/domains/fsm/kernel/ia/StatePair.java
>> ptolemy/domains/csp/demo/DiningPhilosophers/Coordinate.java
>> ptolemy/domains/de/kernel/DEEvent.java
>>
>> # Start checking here
>> ptolemy/domains/gr/kernel/SceneGraphToken.java
>> ptolemy/domains/gr/kernel/Scene2DToken.java
>> ptolemy/graph/mapping/MapMapping.java
>> ptolemy/graph/Graph.java
>> ptolemy/graph/Inequality.java
>> ptolemy/graph/LabeledList.java
>> ptolemy/component/data/type/TupleType.java
>> ptolemy/component/data/TupleToken.java
>> ptolemy/apps/cacheAwareScheduler/kernel/MemoryAddress.java
>> ptolemy/codegen/kernel/CodeGeneratorHelper.java
>> ptolemy/codegen/kernel/CodeStream.java
>> ptolemy/caltrop/ddi/util/DataflowActorInterpreter.java
>> ptolemy/caltrop/ddi/DataflowWithRates.java
>> ptolemy/moml/unit/Unit.java
>> ptolemy/actor/gt/GraphAnalyzer.java
>> ptolemy/actor/gt/GraphAnalyzer.java
>> ptolemy/actor/util/Time.java
>> ptolemy/data/type/MatrixType.java
>> ptolemy/data/type/ObjectType.java
>> ptolemy/data/type/BaseType.java
>> ptolemy/data/type/RecordType.java
>> ptolemy/data/type/ArrayType.java
>> ptolemy/data/type/Type.java
>> ptolemy/data/type/FunctionType.java
>> ptolemy/data/type/FixType.java
>> ptolemy/data/type/UnionType.java
>> ptolemy/data/type/TypeConstant.java
>> ptolemy/data/expr/CachedMethod.java
>> ptolemy/data/properties/token/PropertyToken.java
>> ptolemy/data/properties/PropertyHelper.java
>> ptolemy/data/ShortToken.java
>> ptolemy/data/LongToken.java
>> ptolemy/data/UnsignedByteToken.java
>> ptolemy/data/FloatToken.java
>> ptolemy/data/StringToken.java
>> ptolemy/data/ObjectToken.java
>> ptolemy/data/ComplexToken.java
>> ptolemy/data/ArrayToken.java
>> ptolemy/data/IntMatrixToken.java
>> ptolemy/data/UnionToken.java
>> ptolemy/data/PetiteToken.java
>> ptolemy/data/IntToken.java
>> ptolemy/data/DoubleMatrixToken.java
>> ptolemy/data/BooleanMatrixToken.java
>> ptolemy/data/ActorToken.java
>> ptolemy/data/DoubleToken.java
>> ptolemy/data/FixMatrixToken.java
>> ptolemy/data/RecordToken.java
>> ptolemy/data/BooleanToken.java
>> ptolemy/data/EventToken.java
>> ptolemy/data/LongMatrixToken.java
>> ptolemy/data/FixToken.java
>> ptolemy/data/ComplexMatrixToken.java
>> ptolemy/copernicus/kernel/SideEffectAnalysis.java
>>
>> _Christopher
>>
>> --------
>>
>>
>> It's because when you are comparing one time object with another, bot
h
>> of
>> them have to be actual objects, and null is not an object. You should
>> probably have a:
>> if (a != null && b !=null) when you are using the equals method.
>>
>> Jia
>>
>> On Sun, Jul 6, 2008 at 3:54 PM, Richard Ware <[EMAIL PROTECTED]>
>> wrote:
>>
>> > When I do this,
>> >
>> > Time a = ourDirector.getModelTime();
>> > Time b = null;
>> > boolean comparison = a.equals( b );
>> >
>> > I get a NullPointerException.
>> >
>> > That isn't what the equals() method of a Java object is supposed t
o
>> do.
>> > If
>> > given null as the argument, it's supposed to calmly return the
>> boolean
>> > value "false".
>> >
>> >
>> >
>> >
>> >
>> ------------------------------------------------------------------------
-
>> ---
>> > Posted to the ptolemy-hackers mailing list. Please send
>> administrative
>> > mail for this list to:
>> [EMAIL PROTECTED]
>> >
>>
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