If I overload equals should I still override haschode in java? -

-

i know should override hascode everytime override equals overloading? should still override hashcode?

side note: before posting question i've read should avoid overloading equals in first place i'd still know should if i'd choose overload it.

no hash-based collection ever use overloaded equals() method. it's method, , decide should do. contract entirely yours.

but i'll repeat said in question: shouldn't overload equals() in first place. if do, should @ least make consistent actual equals(object) method avoid confusions. , since should consistent equals(), means need override equals(object), , override hashcode().


Comments

Post a Comment

Popular posts from this blog

sequelize.js - Sequelize group by with association includes id -

-
so when requesting group sequelize follows: return models.workingcalendar .findall({ attributes: [ 'workingcalendar.periodid', 'workingcalendar.date', 'period.name' ], include: [ { model: models.period, attributes: [] } ], where: { getsudoid: currentgetsudo.id, unitplantid: unitplantid }, group: ['workingcalendar.periodid', 'workingcalendar.date', 'period.name'], }); sequelize run query: select [workingcalendar].[id], [workingcalendar].[periodid], [workingcalendar].[date], [period].[name] [workingcalendars] [workingcalendar] left outer join [periods] [period] on [wor...
Read more

java - Android raising EPERM (Operation not permitted) when attempting to send UDP packet after network connection -

-
when responding supplicant_state_changed_action broadcast , attempting send udp packet, exception: java.net.socketexception: sendto failed: eperm (operation not permitted) @ libcore.io.iobridge.maybethrowaftersendto(iobridge.java:542) @ libcore.io.iobridge.sendto(iobridge.java:511) @ java.net.plaindatagramsocketimpl.send(plaindatagramsocketimpl.java:184) @ java.net.datagramsocket.send(datagramsocket.java:305) @ com.mycompany.app.serviceclass.discover(serviceclass.java:355)at com.mycompany.app.serviceclass.access$600(serviceclass.java:39) @ com.mycompany.app.serviceclass$statemachine.run(serviceclass.java:242) @ java.lang.thread.run(thread.java:818) caused by: android.system.errnoexception: sendto failed: eperm (operation not permitted) @ libcore.io.posix.sendtobytes(native method) @ libcore.io.posix.sendto(posix.java:211) @ libcore.io.blockguardos.sendto(blockguardos.java:278) @ libcore.io.iobridge.sendto(iobridge.java:509) @ java.net.plaindat...
Read more

c++ - Migration from QScriptEngine to QJSEngine -

-
i'm migrating qscriptengine code on qjsengine. now, have: class pars { public: static qscriptvalue printmainlog(qscriptcontext* c, qscriptengine* e); }; qscriptvalue pars::printmainlog(qscriptcontext* c, qscriptengine* e) { //some actions return e->globalobject().property(""); } ... qscriptengine engine; ... engine.globalobject().setproperty("printlog",engine.newfunction(pars::printmainlog)); so, user can put printlog("what ever"); in application in , example, qlineedit , function pars::printmainlog evalute. is there way qjsengine? so, user put same printlog("what ever");? way find here , user should put logger.printlog("what ever"); logger class inherited qobject printlog slot.
Read more