Hello, As a follow-up from Joe Darcy's proposal (2013-02-06) to add @FunctionalInterface to some interfaces matching the requirements of FI.
I propose that this improvement is applied to all the VM Java libs. Doing a quick search, I've found some interfaces are not tagged as FunctionaInterfaces but clearly look good candidates : Here is the list of public API I have found so far : java.security.PriviledgeAction java.awt.event.ActionListener java.lang.util.concurrent.Callable java.util.Formattable javax.management.remote.JMXAddressable javax.naming.Referenceable java.awt.print.Printable Private packages also have some : sun.nio.ch.Cancelable sun.nio.ch.Groupable sun.net.www.http.Hurryable sun.misc.Timeable sun.awt.image.ImageFetchable sun.jvm.hotspot.utilities.soql.Callable com.sun.jdi.Locatable Tier lib used/derivated are also impacted (just FYI as it might be out of scope of OpenJDK) : com.sun.xml.internal.ws.api.config.management.Reconfigurable com.sun.xml.internal.ws.api.config.management com.sun.corba.se.spi.ior.MakeImmutable jdk.internal.org.objectweb.asm.util.ASMifiable jdk.internal.org.objectweb.asm.util.Textifiable Some interfaces got two methods 1 "functional like" and 1 getter. I propose to put the getter with a default and let the function unimplemented so matching with the lambda. Hence, the changes should be : javax.security.auth.Destroyable : remove the default from destroy() javax.security.auth.Refreshable : add a default to false to isCurrent() javax.script.Compilable : add a default to the version with String parameter (or the Reader version ?) java.nio.file.Watchable : add a default on the method without modifiers calling the method with modifiers but with empty array javax.accessibility.AccessibleStreamable : add a default version to getMimeTypes() returning a default raw byte stream mime type like application/octet-stream for instance sun.awt.SubRegionShowable : add a default to showIfNotLost() More complex cases exists like : java.lang.Appendable, lot of methods but for the same semantics, should we provide defaults for variants and make it @FI ? java.lang.Cloneable : clearly here it would be nice to get a defaulted clone() as it will improve/ease the clonable semantics (implementing Clonable will bring the default requirement). Here I am assuming there is no side effect of droping cases where you declare Clonable but did not implement clone(). Is it so ? Please forgive my post if this suggestion has not already been debatted but I neither found it in the ML search on GG nor in the hg revs. Also, please not that if the idea is followed, we should performe a more comprehensive search, as mine is only done starting on all "*able.java" files at this time. Best Regards, JB (b...@dev.java.net)
