ps Sstat ffa e t s Java RMI

1
???p???s? S?st?µat?? ??f?f???a? µe t? ???s? Java
RMI

• ?a?a?as?d?? ????a?d???
• ?ast?d?? Ge????a
• ?apaf?t? ?a??a
• ??ts??? St?fa??? ???/???
• Sa?t?a? ?a???e??? ?a?a???t??

2
Ge????

• ?? Java RMI
• ep?t??pe? se efa?µ???? t?? ???s? µe??d?? ap?
  ap?µa???sµ??a a?t??e?µe?a
• ?pa?te?ta? ? ?pa??? e??? RMI client ?a? e??? RMI
  server.
• ?a???e? t? µ??a??sµ? ep???????a? a??µesa st??
  Client ?a? st?? Server
• ep?t??pe? se ?p???d?p?te a?t??e?µe?? t?? Java ?a
  ???s?µ?p????e?, a??µa ?a? a? ? RMI server de? t?
  ??e? ?a?as??a?t?se?

3
?fa?µ???? ?e??t? ???p???t?

• ??a t?p??? efa?µ??? e??p???t? d?µ?????e?
• ap?µa???sµ??a a?t??e?µe?a
• a?af???? se a?t? ?ste ?a e??a? p??sß?s?µa
• pe??µ??e? t??? pe??te? ?a ?a??s??? µe??d??? p???
  se a?t?.
• ??a t?p??? efa?µ??? pe??t?
• ?a?e? µe??d??? p??? se ap?µa???sµ??a a?t??e?µe?a
  µ?s? µ?a? ap?µa???sµ???? a?af????.

4
?e?t?????e? Client ?a? Server

• Server
• ??????s? p???t???? asfa?e?a? (?ta? de? ????µe
  HTTP µp????µe ?a f??t?????µe t??? pe??te? p?? ?a
  ????? p??sßas?)
• S??des? µe t? Registry
• ??aµ??? ??a rmi requests
• Client
• ??????s? p???t???? asfa?e?a? (a? ??e???eta?).
• ??t?p?sµ?? ?a? s??des? µe t?? e??p???t?.
• ??a?µat?p???s? ap?µa???sµ???? ???se??.

5
???es? ?p?µa???sµ???? ??t??e?µ???? ???s? t??
Registry

• ?? RMI p??sf??e? ??a ap?? s??µa ???µat?d?s?a?,
  st? ?p??? ??a ap?µa???sµ??? a?t??e?µe?? d??e?
  st?? ea?t? t?? ??a ???µa ?ta? t???e? ??a p??t?
  f???.
• St? s????e?a ?ata???e?ta? st? RMI registry µe µ?a
  d?ad??as?a e???af??.
• ?? registry s??d?e? t? ???µa t?? a?t??e?µ????
  (??? t? ???µa t?? ???s??) ?a? t? ?d?? t?
  a?t??e?µe??.
• St? Java, ?ta? ??a ap?µa???sµ??? a?t??e?µe??
  e????feta? st? registry µ?a? s???e???µ????
  µ??a???, s??d?ta? µe ??a a?t??e?µe??
  ???µat?d?s?a?.
• ?? ??a pe??t?? ???e? ?a ???s?µ?p???se? ??a
  a?t??e?µe??, t? ?p??? ß??s?eta? se ??a?
  ap?µa???sµ??? ??µß? (?st? ??µß?? A),
• ???e? µ?a a?a??t?s? st? Registry t?? ??µß?? ?.
• ???s?µ?p??e? t? ap?t??esµa t?? a?a??t?s?? ??a ?a
  s??de?e? µe t? ap?µa???sµ??? a?t??e?µe??, ?a? ?a
  pa?eµß???e? t?? µe??d??? t??.

6
???aµ??? f??t?s? ???se??

• ?a???eta? ? d??at?t?ta, ? pe??t?? ?a ste??e? st??
  e??p???t? t? µ???d? p?? ep???µe? ?a e?te?este?.
• G?a ?a ???e? a?t? ?a p??pe? ?a ?p???e? ?a? st??
  pe??t? e? ?e?t?????a e??p???t?? Web.
• ?? de? ?p???e? e??p???t?? Web st? s?st?µa, t?te
  t? RMI e?te?e? a?t?µata ??a ap?? e??p???t? Web,
  ??a t?? a?ta??a?? µ???µ?t?? ?a? t? µetaf??? t??
  ???se??

7
????te?t????? Client ?a? Server
8
?e?t?????a t?? stub

• ?at? t?? ep????s? µ?a? µe??d?? t?? stub, ?????ta?
  ta pa?a??t?
• ??????s? µ?a? s??des?? µe t?? ap?µa???sµ??? JVM
  p?? pe????e? t? ap?µa???sµ??? a?t??e?µe??.
• ????af? ?a? µet?d?s? t?? pa?aµ?t??? st??
  ap?µa???sµ??? JVM.
• ??aµ??? t?? ap?t??sµat?? t?? ap?µa???sµ????
  ep????s?? t?? µe??d??.
• ??????s? t?? ap??t?s?? ? t?? e?a??es?? p??
  ep?st??feta? ap? t?? ap?µa???sµ??? ep????s?.
• ?p?st??f? t?? t?µ?? st?? ?a???ta.

9
?e?t?????a t?? skeleton

• ?ta? t? skeleton ?aµß??e? ??a µ???µa ???e? ta
  e???
• ??aß??e? t?? pa?aµ?t???? ??a t?? ap?µa???sµ???
  µ???d?
• ???e? ep????s? t?? µe??d?? st? p?a?µat???
  ap?µa???sµ??? a?t??e?µe??
• G??fe? ?a? µetad?de? t? ap?t??esµa (t?µ? ?
  e?a??es?) st?? pe??t?.

10
Stubs ?a? Skeletons
11
?pa?t?se??

• ?pa??? e??p???t? Web t??????st?? st?? RMI server
• ??t??es? JRE t?s? st?? RMI client ?s? ?a? st??
  RMI server

12
?e?????sµ?? ?a? ??t?µata ?p?d?se??

• ? ???s? t?? HTTP ??a t?? a?ta??a?? µ???µ?t??
  µe???e? t?? ap?d?s? ?at? t??????st?? µ?a t???
  µe??????
• ??t?µet?p?s? firewalls
• ???at?t?ta tunelling µe t? ???s? e??? e?d??µes??
  ??µß?? µe t?? ?p??? µp????? ?a ep????????s??? ?a?
  ?? d?? ???e?

13
??ad??as?a ?eta???t?s?? ?a? ??t??es?? Client ?a?
Server

• G?a t?? e??p???t?
• ?eta???t?ss? t?? e??p???t?
• javac server.java
• ??µ??????a t?? Skeleton ?a? Stub
• rmic server
• ??????s? t?? registry
• rmiregistry
• ??t??es? t?? e??p???t?
• java server hostname
• G?a t?? pe??t?
• ?eta???t?ss? t?? pe??t?
• javac client.java
• ??t??es? t?? pe??t? ?a? ?a????sµ? t?? ??s?? t??
  stub
• java -Djava.rmi.server.codebase
  http//hostname/username/directory/ clientclass
  hostname method parameters

14
??af????

• http//www.javacoffeebreak.com/articles/javarmi/ja
  varmi.html
• http//java.sun.com/docs/books/tutorial/rmi/
• Andrew S. Tanenbaum and Maarten Van Steen,
  "Distributed Systems Principles and Paradigms",
  Prentice Hall, 2002