java - Command Pattern basics -


suppose have file contents this, combination of config information , commands:

server1 192.168.0.1   server2 192.168.0.12   file1 /home/user1/file1   upload file1 server1   ping server1   replicate server1 shutdown server1   

the command pattern well-suited each of "upload", "ping", "replicate", , "shutdown" can represented command.

however, still have few questions:

1. responsibility parse input?
input file has necessary information files , servers are. parsing? client? receiver? invoker?

2. should parsed information stored?
parsed information first 3 lines go in hashmap. according dzone's blog post,

the receiver has knowledge of carry out request.

so, guessing receiver 1 hashmap stored?

3. can commands return results?
commands "ping" or "shutdown" should indicate happened after command executed. can these commands return values?

  1. whose responsibility parse input?

each line has 2 parts: command name, , arguments. arguments command-specific, should have commandsprovider should:

  • split file lines
  • for each line separate first word , other words
  • create command according first word (you may have commandsregistry knows how find command name)
  • provide arguments command

command pingcommand knows first argument server. in theory, may pair each command argumentsparser takes array of words , configures command it, not sure necessary.

  1. where should parsed information stored?

information stored in command, receiver executes it.

  1. can commands return results?

yes, can implement execute() method like.


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