«

I am new to 1.5.0 and was wondering if anyone knows how to fix the following
syntex/semantic errors. The following code produces the following error
(javac Debug.java Assert.java -xlint):

public class Assert {

"Aryeh M. Friedman" <> writes:

> Assert.java:81: warning: [unchecked] unchecked cast
> found : java.lang.Object
> required: java.lang.Comparable<java.lang.Object>
> if(((Comparable<Object>) val).compareTo(min)<=0)

You can turn off the cast check warning using a variant on the -lint
command line option to javac.

> TestFailException.java:11: warning: [serial] serializable class
> unittest.TestFailException has no definition of serialVersionUID
> public class TestFailException extends RuntimeException
> ^

The same with that warning.

> TestResult.java:49: unittest.TestErrorException is abstract; cannot be
> instantiated
> throw new TestErrorException();
> ^

You need to make a non-abstract subclass.

> TestResultTest.java:57: incompatible types
> found : unittest.TestErrorException
> required: java.lang.Throwable
> } catch(TestErrorException e) {
> ^

Your TestErrorException needs to extend Throwable or one of its
subclasses. Unlike C++, you cannot throw any object you want.

> Assert.assertRange(5,0,9);
> ^

When autoboxing the 5, the compiler uses Integer: That class does not
implement Comparable<Object> but Comparable<Integer> which is not the
same thing.

> AssertTest.java:89:
> assertRange(java.lang.Comparable<java.lang.Object> ,java.lang.Object,java.lang.Object)
> in unittest.Assert cannot be applied to (int,int,int)
> Assert.assertRange(-1,0,9);
> ^

Same thing.

> AssertTest.java:90:
> assertRange(java.lang.Comparable<java.lang.Object> ,java.lang.Object,java.lang.Object)
> in unittest.Assert cannot be applied to (int,int,int)
> Assert.assertRange(10,0,9);
> ^

And again.

The rest are the same you got before.

On Thu, 17 Mar 2005 01:57:23 -0500, "Aryeh M. Friedman"
<> wrote:

>public class Assert {
>
> .
> .
> .
>
> /**
>
> if val is between (inclusive) min and max pass else fail
>
> @param val the "real" value
> @param min the minimal value allowed
> @param max the maximum value allowed
> */
>
> public static void assertRange(Object val,Object min,Object max)
> {
> try {
> if(((Comparable<Object>) val).compareTo(min)<0)
> _assert("assertRange: value to low minimum value is "
> + min + " got " + val);
>
> // repeat test to see if more then max
> } catch(ClassCastException e) {
> TestResult.error(e);
> }
> }
>}

Change the method signature to:

public static <T extends Comparable<T>> void
assertRange(T val, T min, T max)


Then you won't need to do any casts, and the "unchecked" warnings
should go away.