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Class oaa.agentlib.AgentLib

oaa.agentlib.AgentLib

public class AgentLib

client

Reference to the communication layer

connected

Status of the connection

copyright

Copyright information.

KSname

Knowledge source name

loop

To control the thread that performs the main oaa loop

rcsId

Version information.

received

Current incoming buffer

server

Reference to the communication layer (If working as server)

solveParams

Current parameters used to solve predicates

AgentLib(AgentInterface, String)

Constructor.

AgentLib(AgentInterface, String, String)

Constructor.

addRemoteTrigger(String, String, String, String, String, String)

Adds a trigger to the appropriate agent.

addTrigger(String, String, String, String)

Adds a trigger to the appropriate agent.

addTriggerToKs(String, String, String, String, String)

Adds a trigger to the specified agent.

args(String)

Extract the params from a term "head(params)"

argument(String, int)

Returns the nth argument in a term

argumentAsInt(String, int)

Returns the nth argument in a term as integer

delaySolution()

Defer solving a doEvent request until a later time.

deref(String, DynArray)

See if a variable can be resolved using existing variable bindings

disconnect()

Disconnects client from Facilitator.

doubleQuotes(String)

Doubles any "'" in the string, to prepare the string to be surrounded by "'".

extractEvent(String)

Parses an event (message from the facilitator) and returns KS,Event.

first(String)

Takes a list of terms (comma separated) and returns the first (car) one.

func(String)

Extract the head from a term "head(params)"

functor(String)

Splits a string containing a prolog-style term into a functor and arguments.

getEvent(boolean)

Reads an event from the TCP stream.

ifTraceOn(String, String)

Print a trace message if TraceOn is set.

isList(String)

Returns true if the term is an ICL list (in form [1,2,3])

isVar(String)

Returns true if the term is an ICL variable

listLen(String)

Returns the length of a comma separated list of ICL terms

listToTerms(String)

Converts an incoming ICL list [elt1, elt2, elt3] form) into a list of terms, on which we can use list_len, NthElt, etc.

nthElt(String, int)

Returns the Nth term in a list of terms

oaaLoop(boolean)

Heart of the application, provides the get_event-interpret loop for a java application.

oaaReady(boolean)

Let the Server know that setupCommunication is done any personal initializations.

paramValue(String, String)

Extracts the value from a parameter list

pollUntilEvent(String)

Waits until a matching event is returned from server

postEvent(String)

Sends an event (message) to the facilitator.

readBB(String, String)

Retrieves information from Facilitator's global data store.

readBB(String, String, boolean)

Retrieves information from Facilitator's global data store.

readBB(String, String, String)

Retrieves information from Facilitator's global data store.

readBB(String, String, String, boolean)

Retrieves information from Facilitator's global data store.

readSetupFile(String[])

Finds the host and port values for the facilitator, and possibly the name for the client agent, looking on the command line and/or in the setup file.

removeQuotes(String)

Removes leading and trailing ' and " marks

replaceBB(String, String, String)

Changes item value from Old to New.

rest(String)

Takes a list of terms (comma separated) and returns the rest (cdr) one.

retractBB(String, String)

Remove item from global data on blackboard.

returnDelayedSolutions(String, String)

Sends the solutions to a delayed event to the Facilitator, and removes the event from the delay table.

run()

Implements the run method of the thread (parent) class.

setupCommunication(String, String, int, String, boolean)

Establishes tcp connection to the facilitator.

solve(String, String)

Requests data or actions from distributed agents

startAsServer(String, int)

Starts an agent as a server.

term(String)

Takes a list of terms (comma separated) and returns the first (car) and rest (cdr) of the list.

undoubleQuotes(String)

Converts any '' marks inside a string to just '.

unify(String, String)

Perform true unification and return resulting term, or "" if failure

writeBB(String, String)

Add information to global data stored on blackboard server.

writeOnceBB(String, String)

Add information to global data stored on blackboard server at most one times (if exists, doesn't write).

writeReplaceBB(String, String)

Add information to global data stored on blackboard server, replacing old information with new information.

 public static final String copyright

Copyright information.

 public static final String rcsId

Version information.

 public CommLib client

Reference to the communication layer

 public CommServer server

Reference to the communication layer (If working as server)

 public String received

Current incoming buffer

 public boolean loop

To control the thread that performs the main oaa loop

 public String KSname

Knowledge source name

 public String solveParams

Current parameters used to solve predicates

 public static boolean connected

Status of the connection

 public AgentLib(AgentInterface a,
                 String inKSName)

Constructor.

Parameters:

AgentInterface - The interface between the agentlib and the agent

inKSName - Agent name

Remarks:

"KS" in the second argument stands for Knowledge Source, which

historically is synonymous with Agent

See Also:

AgentInterface

 public AgentLib(AgentInterface a,
                 String m1,
                 String m2)

Constructor.

Parameters:

AgentInterface - The interface between the agentlib and the agent

m1 - Agent name

m2 - Agent knowledge source name

Remarks:

This is obsolete; has been retained for backwards compatibility.

New code should use the 2-argument version instead.

See Also:

AgentInterface

 public void run()

Implements the run method of the thread (parent) class.

 public static String[] readSetupFile(String args[])

Finds the host and port values for the facilitator, and possibly the name for the client agent, looking on the command line and/or in the setup file.

Parameters:

args - Command line arguments. May contain :
-oaa_port PORT_NUMBER : Facilitator's port number
-oaa_host HOST_NAME : Facalitator's host
-oaa_name NAME : Agent name
-oaa : Ask for an automatic connection to the facilitator

Returns:

- String[0] : Port for the server process
- String[1] : Host for the server process
- String[2] : Name for agent provided on command line
- String[3] : Boolean: should autoconnect? Yes if -oaa or -oaa_host given on command line.

Remarks:

The function first looks on the command line (args). If it fails to

find BOTH host and port there, then it tries to find the information

in a setup.pl file (looking first in the current directory, then in the

root directory). If an agent name is found on the command line,

that is also returned.

 public boolean setupCommunication(String KS,
                                   String Host,
                                   int Port,
                                   String Solvable,
                                   boolean ServerQP32)

Establishes tcp connection to the facilitator.

Parameters:

KS: - Name for the Agent

Host: - host to connect to

Port: - port to connect to

Solvable: - ICL-formatted list of solvables provided by the Agent

ServerQP32: - Not used currently -- always pass in True

Returns:

True if the connection to the facilitator succeeded, False otherwise

Remarks:

"KS" in the first argument stands for Knowledge Source, which

historically is synonymous with Agent.

 public void disconnect()

Disconnects client from Facilitator.

 public void startAsServer(String host,
                           int port)

Starts an agent as a server.

Parameters:

host: - host number

port: - port number

Remarks:

This method is normally called only by a facilitator, not by a client

agent.

 public void postEvent(String Event)

Sends an event (message) to the facilitator.

Parameters:

Event: - event to be posted

 public String[] extractEvent(String one_event)

Parses an event (message from the facilitator) and returns KS,Event.

Parameters:

one_event: - event to be parsed

Returns:

- String[0] : KS
- String[1] : Event
- null if an error occurs (The event is not correctly wrapped)

Remarks:

If the event is in form "term(Result)." then String[0] = null, String[1] = Event

If the event is in form "term(KS,Result)." then String[0] = KS, String[1] = Event

 public void writeBB(String Item,
                     String Data)

Add information to global data stored on blackboard server.

Parameters:

Item: - type of data being written

Data: - value for the data type

Remarks:

ex: write_bb(name, "Adam Cheyer") adds name("Adam Cheyer") on blackboard

 public void writeReplaceBB(String Item,
                            String Data)

Add information to global data stored on blackboard server, replacing old information with new information.

Parameters:

Item: - type of data being written

Data: - value for the data type

 public void writeOnceBB(String Item,
                         String Data)

Add information to global data stored on blackboard server at most one times (if exists, doesn't write).

Parameters:

Item: - type of data being written

Data: - value for the data type

 public void retractBB(String Item,
                       String Data)

Remove item from global data on blackboard.

Parameters:

Item: - type of data being written

Data: - value for the data type

Remarks:

If Data points to a var, it will remove any value of type "item"

 public void replaceBB(String Item,
                       String OldData,
                       String NewData)

Changes item value from Old to New.

Parameters:

Item: - type of data being written

Data: - value for the data type

NewData: - newdata: new value of data

 public String readBB(String Item,
                      String Data,
                      boolean Async)

Retrieves information from Facilitator's global data store.

Parameters:

String - item: type of data being written

String - data: value for the data type, variable if requesting values

boolean - Async: Whether should return results asynchronously

String - answers: list containing results.

Remarks:

If Async is True, returns immediately with the empty list ("[]").

In this case, the doEvent method will be called with the results

when they arrive.

 public String readBB(String Item,
                      String Data)

Retrieves information from Facilitator's global data store.

Parameters:

String - item: type of data being written

String - data: value for the data type, variable if requesting values

Remarks:

Returns results synchronously

See Also:

readBB

 public String readBB(String KS,
                      String Item,
                      String Data,
                      boolean Async)

Retrieves information from Facilitator's global data store.

Parameters:

String - KS: (numeric) id of Agent having "ownership" of the data

String - item: type of data being written

String - data: value for the data type, variable if requesting values

String - answers: list containing results.

Remarks:

Allows to specify a KS

See Also:

readBB

 public String readBB(String KS,
                      String Item,
                      String Data)

Retrieves information from Facilitator's global data store.

Parameters:

String - KS: id of KS (agent) to read data about

String - item: type of data being written

String - data: value for the data type, variable if requesting values

String - answers: list containing results.

Remarks:

Allows to specify a KS

Returns results synchronously

See Also:

readBB

 public void addTrigger(String Kind,
                        String Type,
                        String Condition,
                        String Action)

Adds a trigger to the appropriate agent.

Parameters:

String - Kind: may be 'test', 'data', or 'alarm'

String - Type: may be 'when' or 'if' (single-use), or 'whenever' (permanent)

String - Condition: test condition

String - Action: action to be performed if Condition succeeds

Remarks:

add_trigger/4 does not require a KS to be specified, because the KS

will be determined automatically:

-data: always installed on Server

-test: installed on appropriate agent by solvable

-alarm: installed on alarm agent

For 'event' triggers, use add_trigger_on_ks()

addRemoteTrigger provides a more general functionality for creating

a trigger

 public void addTriggerToKs(String KS,
                            String Kind,
                            String Type,
                            String Condition,
                            String Action)

Adds a trigger to the specified agent.

Parameters:

String - KS: KS on which the trigger should be installed

String - Kind: may be 'test', 'event', or 'alarm' (not 'data'!)

String - Type: may be 'when', 'if' (single), 'whenever' (permanent)

String - Condition: test condition

String - Action: action to be performed if Condition succeeds

Remarks:

Cannot be used to install a data trigger.

addRemoteTrigger provides a more general functionality for creating

a trigger.

 public void addRemoteTrigger(String Kind,
                              String Type,
                              String OpMask,
                              String Template,
                              String Condition,
                              String Action)

Adds a trigger to the appropriate agent.

Parameters:

String - Kind: may be 'test', 'data', or 'alarm'

String - Type: may be 'when', 'if' (single), 'whenever' (permanent)

String - OpMask: on_write, on_replace, on_retract, on_write_replace, or a list combining several of these

String - Template: template against which to match the trigger (e.g. data, or test)

String - Condition: test condition

String - Action: action to be performed if Template is matched and Condition succeeds

Remarks:

add_trigger/6 does not require a KS to be specified, because the KS

will be determined automatically:

-data: always installed on Server

-test: installed on appropriate agent by solvable

-alarm: installed on alarm agent

For 'event' triggers, use add_trigger_on_ks()

 public void ifTraceOn(String msg,
                       String arg)

Print a trace message if TraceOn is set.

Parameters:

msg: - message to be printed

arg: - arguments to be printed

 public String delaySolution()

Defer solving a doEvent request until a later time. This procedure should be called in doEvent() when a programmer wants to return from doEvent() without returning an immediate solution. The return value should be returned from doEvent and should also be saved in a variable, which should be passed to returnDelayedSolutions(Var,Solutions) when ready.

 public void returnDelayedSolutions(String var,
                                    String answers)

Sends the solutions to a delayed event to the Facilitator, and removes the event from the delay table.

Parameters:

var: - the value previously returned by function delaySolution()

answers: - the solution list for the delayed event

Remarks:

If answer=NULL, an empty solution list ([]) is sent to the Facilitator.

 public static String func(String inTerm)

Extract the head from a term "head(params)"

Parameters:

String - predicate: In form "head(arg1, arg2, ...)"

Returns:

A string containing the functor of a prolog-style term.

 public static String args(String inTerm)

Extract the params from a term "head(params)"

Parameters:

String - predicate: In form "head(arg1, arg2, ...)"

Returns:

A string containing the arguments of a prolog-style term.

Remarks:

If no arguments exist, returns an empty string.

 public static String[] functor(String predicate)

Splits a string containing a prolog-style term into a functor and arguments.

Parameters:

predicate: - In form "a(arg1, arg2, ...)"

Returns:

outputs[] : array of strings

- outputs[0] contains "a"

- outputs[1] contains "arg1, arg2, ..."

Remarks:

If no arguments exist, the empty string is returned in outputs[].

 public static String[] term(String terms)

Takes a list of terms (comma separated) and returns the first (car) and rest (cdr) of the list.

Parameters:

terms: - a comma-separated list of ICL (prolog-style) terms.

Returns:

String outputs[] : array of strings

- outputs[0] : the first term in the list

- outputs[1] : the rest of the terms

Remarks:

This method, and others calling for a "comma-separated" list,

should NOT be passed an ICL list; that is, the list should not

begin and end with square brackets. Before calling this method,

square brackets should be removed by a call to listToTerms.

Terms may be nested arbitrarily deep; e.g., terms could be

"a(b(c(d,1))), X".

 public static String first(String inTerm)

Takes a list of terms (comma separated) and returns the first (car) one.

Parameters:

inTerms: - a comma-separated list of ICL terms

Returns:

The first term in the list

 public static String rest(String inTerm)

Takes a list of terms (comma separated) and returns the rest (cdr) one.

Parameters:

inTerms: - a list of ICL terms

Returns:

The rest of the list

 public static String nthElt(String list,
                             int n)

Returns the Nth term in a list of terms

Parameters:

list: - a string containing a comma-separated list of terms

n: - index into a list (nth term)

Returns:

String elt: the nth term in the list.

Remarks:

Returns null if index is longer than number of elements

The first element is at index 1 (not 0)

 public static String argument(String predicate,
                               int n)

Returns the nth argument in a term

Parameters:

predicate: - a prolog-style term: eg func(a1,a2,...)

n: - index into a list (nth term)

Returns:

String argument: the nth argument in the term. eg (a2 if n = 2)

Remarks:

Returns null if index is longer than number of elements

The first element is at index 1 (not 0)

 public static int argumentAsInt(String predicate,
                                 int n)

Returns the nth argument in a term as integer

Parameters:

predicate: - a prolog-style term: eg func(a1,a2,...)

n: - index into a list (nth term)

Returns:

The nth argument in the term as an integer

Remarks:

Returns null if index is longer than number of elements

The first element is at index 1 (not 0)

 public static boolean isList(String s)

Returns true if the term is an ICL list (in form [1,2,3])

Parameters:

s: - a string containing an ICL term

Returns:

True if the term is a list

 public static boolean isVar(String t)

Returns true if the term is an ICL variable

Parameters:

String - term: a string containing an ICL term (or variable)

Returns:

True if the term is a variable

 public static String paramValue(String aList,
                                 String param)

Extracts the value from a parameter list

Parameters:

aList: - a parameter list, in the form "[attr1(Value1), attr2(Value2)]"

param: - parameter to extract (e.g. attr1)

Returns:

Value of parameter or null if not found

 public static String doubleQuotes(String s)

Doubles any "'" in the string, to prepare the string to be surrounded by "'".

Parameters:

s: - a string containing ICL terms

Returns:

The string with any "'" --> "''"

 public static String undoubleQuotes(String s)

Converts any '' marks inside a string to just '. Single quotes inside strings will be doubled when coming from ICL

Parameters:

s: - a string containing ICL terms

Returns:

The string with all '' --> '

 public static String removeQuotes(String s)

Removes leading and trailing ' and " marks

Parameters:

s: - a string containing ICL terms

Returns:

The string minus leading and trailing quotes

 public static int listLen(String list)

Returns the length of a comma separated list of ICL terms

Parameters:

list: - An comma-separated list of ICL terms

Returns:

The length of the list

 public static String listToTerms(String s)

Converts an incoming ICL list [elt1, elt2, elt3] form) into a list of terms, on which we can use list_len, NthElt, etc. i.e. a comma-separated list "elt1, elt2, etl3". Basically, just removes the brackets...

Parameters:

s: - a list in ICL syntax

Returns:

The inner incoming list. (Removes brackets)

 public String deref(String var,
                     DynArray var_bindings)

See if a variable can be resolved using existing variable bindings

Parameters:

var: - will return value if one can be found in var_bindings

var_bindings: - A list stored with var/value in l[N]/l[N+1]

 public String unify(String term1,
                     String term2)

Perform true unification and return resulting term, or "" if failure

Parameters:

term1: - first term

term2: - second term

Returns:

If the two terms unify, returns the unified term. Otherwise returns "", representing failure

 public String pollUntilEvent(String wait_event)

Waits until a matching event is returned from server

Parameters:

wait_event: - event template we are waiting for

Returns:

The specific event returned

 public String solve(String Goal,
                     String Params)

Requests data or actions from distributed agents

Parameters:

goal: - an ICL goal to be solve/performed

params: - control parameters describing how the goal should be sent/resolved (see below).

Returns:

A list containing solutions to the requested goal. The answer value "[]" constitutes failure of the goal.

OAA parameters:
The params argument is a list which may contain:

cache : cache all solutions locally

level_limit(N) : highest number of levels to climb for solutions

address(KS) : ask a specific KS to solve goal

and_parallel : and-parallel solve of Goal list

or_parallel : or-parallel solve of Goal list

test(Test) : only solve goal on blackboards where Test succeeds locally

broadcast : just disseminate message, do not request results

asynchronous : solve will not block until solution returns, the solutions will be returned asynchronously in solved(FromKs,Goal,Params,Solutions) messages which should be handled by in doEvent()

solution_limit(N): limits the number of solutions found. Currently only works for 1...to N

time_limit(N) : Waits a maximum of N seconds before returning (failure if no solution)

 public String getEvent(boolean IsServer)

Reads an event from the TCP stream.

Returns:

The event read.

Remarks:

Called by CommLib.java each time something is received

 public void oaaReady(boolean print_ready)

Let the Server know that setupCommunication is done any personal initializations. Should be called by the agent just before entering the MainLoop().

 public void oaaLoop(boolean print_ready)

Heart of the application, provides the get_event-interpret loop for a java application.

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