provided.music
Class APhraseVisitor

java.lang.Object
  provided.music.APhraseVisitor

All Implemented Interfaces:

IPhraseVisitor

public abstract class APhraseVisitor
extends java.lang.Object
implements IPhraseVisitor

Command-based implementation of IPhraseVisitor that uses IPhraseVisitorCmds stored in a hash table.

Author:

swong

Field Summary

private java.util.Map<java.lang.String,IPhraseVisitorCmd>	cmds The dictionary of commands, implemented using a hash table.
private IPhraseVisitorCmd	defaultCmd The default command to use when caseAt is called with an ID that is not in the hashtable as a key.

Constructor Summary

APhraseVisitor()
Constructor that installs a default cmd that throws an IllegalArgumentException on any unknown host.

APhraseVisitor(IPhraseVisitorCmd defaultCmd)
Constructor that sets the default cmd to the supplied cmd.

Method Summary

void	addCmd(java.lang.String id, IPhraseVisitorCmd cmd) Add the given command to the dictionary, associated with the given id value.
java.lang.Object	caseAt(java.lang.String id, IPhrase host, java.lang.Object... params) Runs the command associated with the given id, passing along the given host and vararg parameters.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

defaultCmd

private IPhraseVisitorCmd defaultCmd

The default command to use when caseAt is called with an ID that is not in the hashtable as a key.

cmds

private java.util.Map<java.lang.String,IPhraseVisitorCmd> cmds

The dictionary of commands, implemented using a hash table.

Constructor Detail

APhraseVisitor

public APhraseVisitor()

Constructor that installs a default cmd that throws an IllegalArgumentException on any unknown host.

APhraseVisitor

public APhraseVisitor(IPhraseVisitorCmd defaultCmd)

Constructor that sets the default cmd to the supplied cmd.

Parameters:

defaultCmd - the default cmd to use.

Method Detail

caseAt

public java.lang.Object caseAt(java.lang.String id,
                               IPhrase host,
                               java.lang.Object... params)

Runs the command associated with the given id, passing along the given host and vararg parameters. If there is no cmd associated with the given id in the dictionary, then use the default cmd.

Specified by:

caseAt in interface IPhraseVisitor

Parameters:

id - The ID value that identifies the host

host - The host IPhrase object

params - vararg list of parameters that might be used. Can be called with no input params.

Returns:

the result of executing the associated cmd.

addCmd

public void addCmd(java.lang.String id,
                   IPhraseVisitorCmd cmd)

Add the given command to the dictionary, associated with the given id value.

Parameters:

id - The id of the host that will use this command

cmd - The command that will be run when the host calls for it.