Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Should Mirror Operations Be Dropped?,David BoothW3C Fellow/Hewlett-Packard,Current Status,Four Message Exchange Patterns(MEPs):,Input-Output(was Request-Response),Input-Only(was One-Way),Output-Input,(was Solicit-Response),Output-Only,(was Notification),Mirror ops:Output-Input,Output-Only,Problems with Mirror Ops,Multiple interpretations:event?callback?,Little evidence of use,Where to get the Clients address?,Inconsistent treatment of Faults?,Input-Output:Fault is an alternate,Output,Input-Only:(no Faults),Output-Input:Fault is an alternate,Input,Output-Only:(no Faults),What I Did,Abstract analysis:,Suppose we used WS descriptions in a larger context.Would we want mirror ops?,Example:Markets,Potential Application:Markets,Multiple Clients,Multiple Services,Any Client can talk to any Service(of the same type),Service,A3,Service,A2,Client,A1,Service,B3,Service,B2,Service,B1,Markets,Ways to match Client and Service:,Client and Service,share,same WSDL,Client and Service have,complementary,WSDLs,Service,A3,Service,A2,Client,A1,Service,B3,Service,B2,Service,B1,Shared Service Descriptions,Role must be separately indicated:,Client:Im a T Client,Service:Im a T Service,Binding information is lopsided(Service-centric),Binding has Service-specific info(address),Where is Client-specific info placed?,Service,A3,Service,A2,Client,A1,Service,B3,Service,B2,Service,B1,T,Shared:One WSDL per Service,T1,T2,T3 could be specific to B1,B2,B3,T1 has B1s address,T2 has B2s address,etc.,B1:Im a T1 Service,B2:Im a T2 Service,etc.,Each Client could reference all T1,T2,T3:Im a T1Client,a T2 Client and a T3 Client,Service,A3,Service,A2,Client,A1,Service,B3,Service,B2,Service,B1,T3,T2,T1,Shared:Referencing a Common T,T1,T2,T3 could reference generic T,T1 has B1s address,T2 has B2s address,etc.,B1:Im a T1,T is Service-centric,but not identity-centric(I.e.,no address),Client could reference generic T:,Im a T Client,Service,A3,Service,A2,Client,A1,Service,B3,Service,B2,Service,B1,T3,T2,T1,T,TA3,TA2,Shared:Client,Service Ref T,TA1,TA2,TA3,TB1,TB2,TB3 are all identity-specific,TA1:A1 is a T Client,TB1:B1 is a T Service,T does not contain address,Service,A3,Service,A2,Client,A1,Service,B3,Service,B2,Service,B1,TB3,TB2,TB1,T,TA1,TA3,TA2,Shared:Role-Specific Descriptions,TC and TS are role-specific,but not identity-specific:,TC:I am a T Client,TS:I am a T Service,T does not contain address or role info,Service,A3,Service,A2,Client,A1,Service,B3,Service,B2,Service,B1,TB3,TB2,TB1,T,TA1,TC,TS,TA3,TA2,Shared:Conclusion,Sharing requires mirror ops,only,if you think theyre important,Need Output-Input?,Need Output-Only?,Service,A3,Service,A2,Client,A1,Service,B3,Service,B2,Service,B1,TB3,TB2,TB1,T,TA1,Complementary Service Descriptions,Symmetric(Peer-to-Peer),T describes Service;T describes Client,T,T indicate:,Generic info(T),Role-specific info(Client vs.Service),Identity-specific info(address),Requires(complementary)equivalence to match,T,T,Service,B3,Service,B2,Service,B1,Service,A3,Service,A2,Client,A1,Complementary:Observation,Complementary approach,requires,mirror ops,Inputs of T are Outputs of T,Outputs of T are Inputs of T,T,T,Service,B3,Service,B2,Service,B1,Service,A3,Service,A2,Client,A1,TA3,TA2,Complementary:Identity-Specific Info,TA1,TA2,TA3,TB1,TB2,TB3 are all identity-specific,TA1:A1 is a T,TB1:B1 is a T,T,T do not contain addresses,Service,A3,Service,A2,Client,A1,Service,B3,Service,B2,Service,B1,TB3,TB2,TB1,T,TA1,T,Conclusions,Mirror ops add flexibility,Identity-specific info(address)should be,separated,from shared info,Other binding info can be shared:transport protocol,etc.,END,WSDL Information Sharing,From,most,shared to,least,shared:,Message types,Message direction(input/output),Transport protocol,Message encoding,Address(,Not,shared!),The least shared info should be latest bound,Observations on MEPs,MEPs,Sequence:,A sends W to B,B sends X to A,A sends Y to B,B sends Z to A,X,Y,Z,W,1,2,3,4,Bs View,As View,MEP:Bs View,One big MEP:,PWXYZ:Receive W,send X,receive Y,send Z,Bs View,X,Y,Z,W,1,2,3,4,As View,PWXYZ,MEP:Bs View,Two Request-Response MEPs:,PWX:Receive W,send X,PYZ:Receive Y,send Z,Bs View,X,Y,Z,W,1,2,3,4,As View,PWX,PYZ,MEP:Bs View,Q:Should B care how A models its interactions with B?,A:Of course not.,Bs View,X,Y,Z,W,1,2,3,4,As View,PWX,PYZ,MEP:As View 1,Two Solicit-Response MEPs:,PWX:Send W,receive X,PYZ:Send Y,receive Z,Bs View,X,Y,Z,W,1,2,3,4,As View,PWX,PYZ,MEP:As View 2,Three MEPs:,PW:Send W(Notification),PXY:Receive X,send Y(Request-Response),PZ:Receive Z(One-way),Bs View,X,Y,Z,W,1,2,3,4,As View,PXY,PW,PZ,MEP:As View 3,Four MEPs:,PW:Send W(Notification),PX:Receive X(One-way),PY:Send Y(Notification),PZ:Receive Z(One-way),Bs View,X,Y,Z,W,1,2,3,4,As View,PX,PW,PZ,PY,MEP:As View 4,Two MEPs:,PWX:Send W,receive X(Solicit-Response),PYZ:Send Y,receive Z(Request-Response),Bs View,X,Y,Z,W,1,2,3,4,As View,PWZ,PXY,MEPs