Use default for UnitConverter.isLinear() and isIdentity() about unit-api HOT 3 CLOSED

Should we really provide such default method? In the collection framework, all default methods provide a default implementation that fulfill the method contract documented in the javadoc. They may not be optimal - subclasses override those default methods for providing a more efficient implementation - but not for changing their behavior.

In the case of isLinear(), a default implementation returning isIdentity() does not fulfill the method contract. A return value of true means that the converter is linear (okay), but a return value of false does not mean that the converter is non-linear. It does not seem to me that the javadoc allowed this flexibility.

from unit-api.

Currently the same is done in AbstractConverter. At least for isIdentity(). Which always seems to be false except in the actual Identity converter class.
If you think isLinear() may better be excluded from providing a default, please create a separate ticket.

from unit-api.

Filled a new issue #76. As explained in this issue, I think it is okay to have those default implementation in AbstractConverter. Only in Unit-API, I think we should not not provide any default method except when we can do that in a way that really fulfill the method contract. For the reference implementation, this is different for the reason explained in #76.

from unit-api.