Package astra.util

Class TupleSpace

java.lang.Object

astra.core.Module

astra.util.TupleSpace

public class TupleSpace
extends Module

This class implements an in JVM tuple space.

Tuple spaces are shared spaces are an alternative (to message passing) mechanism for implementing coordination mechanisms in multi-agent systems. This class implements an in JVM tuple space.

To use this class, you will need to import this class and add it as a module:

package ts;

import astra.util.TupleSpace;

agent Template {
module TupleSpace ts;
}


Author:

Rem Collier

Nested Class Summary

Nested classes/interfaces inherited from class astra.core.Module

Module.ACTION, Module.EVENT, Module.FORMULA, Module.SENSOR, Module.SUPPRESS_NOTIFICATIONS, Module.TERM

Field Summary

Fields inherited from class astra.core.Module

agent

Constructor Summary

Constructors

Constructor	Description
TupleSpace()

Method Summary

Modifier and Type	Method	Description
Boolean	getBoolean(String id, String key)	Term to retrieve a boolean from a space stored under a given key
char	getChar(String id, String key)	Term to retrieve a char from a space stored under a given key
Double	getDouble(String id, String key)	Term to retrieve a double from a space stored under a given key
Float	getFloat(String id, String key)	Term to retrieve a float from a space stored under a given key
Integer	getInt(String id, String key)	Term to retrieve an int from a space stored under a given key
ListTerm	getList(String id, String key)	Term to retrieve a list from a space stored under a given key
Long	getLong(String id, String key)	Term to retrieve a long from a space stored under a given key
Object	getObject(String id, String key)	Term to retrieve an object from a space stored under a given key
ListTerm	getSpaceList()	Return a list of the spaces that the agent has joined.
String	getString(String id, String key)	Term to retrieve a string from a space stored under a given key
Formula	hasSpace(String id)	Formula to check whether a space exists
Formula	hasTuple(String id, String key)	Formula to check whether a space contains a key
boolean	join(String id)	Action that lets the agent join a tuple space
boolean	leave(String id)	Action for an agent to leave a tuple space
boolean	post(String id, String key, boolean value)	Action to post a boolean to the specified space.
boolean	post(String id, String key, char value)	Action to post a char to the specified space.
boolean	post(String id, String key, double value)	Action to post an double to the specified space.
boolean	post(String id, String key, float value)	Action to post an float bject to the specified space.
boolean	post(String id, String key, int value)	Action to post an int to the specified space.
boolean	post(String id, String key, long value)	Action to post an long to the specified space.
boolean	post(String id, String key, ListTerm value)	Action to post an list to the specified space.
boolean	post(String id, String key, Object value)	Action to post an object to the specified space.
boolean	post(String id, String key, String value)	Action to post a string to the specified space.

Methods inherited from class astra.core.Module

inline, setAgent

Methods inherited from class java.lang.Object

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

Constructor Detail

TupleSpace

public TupleSpace()

Method Detail

join

public boolean join(String id)

Action that lets the agent join a tuple space

This action should be used to connect an agent to a tuple space. If a tuple space with the given id exists, then the agent joins that space, alternatively, the space is first created and then the agent joins it.

Parameters:

id - the id of the tuple space that the agent is to join.

Returns:

true if the action succeeds, false otherwise

leave

public boolean leave(String id)

Action for an agent to leave a tuple space

This action should be used when an agent wants to leave a tuple space. If the tuple space is empty after the agent has left, then the space is deleted.

This action fails if:

1. The space does not exist.
2. The agent is not in the space.

Parameters:

id - the id of the space.

Returns:

true if the action succeeds, false otherwise

post

public boolean post(String id,
                    String key,
                    Object value)

Action to post an object to the specified space.

This action will fail if the space does not exist.

Parameters:

id - the space id

key - the key that the object will be stored under

value - the object

Returns:

true if the action succeeds, false otherwise

post

public boolean post(String id,
                    String key,
                    String value)

Action to post a string to the specified space.

This action will fail if the space does not exist.

Parameters:

id - the space id

key - the key that the string will be stored under

value - the string

Returns:

true if the action succeeds, false otherwise

post

public boolean post(String id,
                    String key,
                    int value)

Action to post an int to the specified space.

This action will fail if the space does not exist.

Parameters:

id - the space id

key - the key that the int will be stored under

value - the int

Returns:

true if the action succeeds, false otherwise

post

public boolean post(String id,
                    String key,
                    long value)

Action to post an long to the specified space.

This action will fail if the space does not exist.

Parameters:

id - the space id

key - the key that the long will be stored under

value - the long

Returns:

true if the action succeeds, false otherwise

post

public boolean post(String id,
                    String key,
                    float value)

Action to post an float bject to the specified space.

This action will fail if the space does not exist.

Parameters:

id - the space id

key - the key that the float will be stored under

value - the float

Returns:

true if the action succeeds, false otherwise

post

public boolean post(String id,
                    String key,
                    double value)

Action to post an double to the specified space.

This action will fail if the space does not exist.

Parameters:

id - the space id

key - the key that the double will be stored under

value - the double

Returns:

true if the action succeeds, false otherwise

post

public boolean post(String id,
                    String key,
                    char value)

Action to post a char to the specified space.

This action will fail if the space does not exist.

Parameters:

id - the space id

key - the key that the char will be stored under

value - the char

Returns:

true if the action succeeds, false otherwise

post

public boolean post(String id,
                    String key,
                    boolean value)

Action to post a boolean to the specified space.

This action will fail if the space does not exist.

Parameters:

id - the space id

key - the key that the boolean will be stored under

value - the boolean

Returns:

true if the action succeeds, false otherwise

post

public boolean post(String id,
                    String key,
                    ListTerm value)

Action to post an list to the specified space.

This action will fail if the space does not exist.

Parameters:

id - the space id

key - the key that the list will be stored under

value - the list

Returns:

true if the action succeeds, false otherwise

getString

public String getString(String id,
                        String key)

Term to retrieve a string from a space stored under a given key

This term fails if there is not tuple space with the given id.

Parameters:

id - the space id

key - the key that the value is stored under

Returns:

the value associated with key

getInt

public Integer getInt(String id,
                      String key)

Term to retrieve an int from a space stored under a given key

This term fails if there is not tuple space with the given id.

Parameters:

id - the space id

key - the key that the value is stored under

Returns:

the value associated with key

getLong

public Long getLong(String id,
                    String key)

Term to retrieve a long from a space stored under a given key

This term fails if there is not tuple space with the given id.

Parameters:

id - the space id

key - the key that the value is stored under

Returns:

the value associated with key

getFloat

public Float getFloat(String id,
                      String key)

Term to retrieve a float from a space stored under a given key

This term fails if there is not tuple space with the given id.

Parameters:

id - the space id

key - the key that the value is stored under

Returns:

the value associated with key

getDouble

public Double getDouble(String id,
                        String key)

Term to retrieve a double from a space stored under a given key

This term fails if there is not tuple space with the given id.

Parameters:

id - the space id

key - the key that the value is stored under

Returns:

the value associated with key

getList

public ListTerm getList(String id,
                        String key)

Term to retrieve a list from a space stored under a given key

This term fails if there is not tuple space with the given id.

Parameters:

id - the space id

key - the key that the value is stored under

Returns:

the value associated with key

getObject

public Object getObject(String id,
                        String key)

Term to retrieve an object from a space stored under a given key

This term fails if there is not tuple space with the given id.

Parameters:

id - the space id

key - the key that the value is stored under

Returns:

the value associated with key

getChar

public char getChar(String id,
                    String key)

Term to retrieve a char from a space stored under a given key

This term fails if there is not tuple space with the given id.

Parameters:

id - the space id

key - the key that the value is stored under

Returns:

the value associated with key

getBoolean

public Boolean getBoolean(String id,
                          String key)

Term to retrieve a boolean from a space stored under a given key

This term fails if there is not tuple space with the given id.

Parameters:

id - the space id

key - the key that the value is stored under

Returns:

the value associated with key

hasTuple

public Formula hasTuple(String id,
                        String key)

Formula to check whether a space contains a key

Parameters:

id - the space id

key - the key

Returns:

returns formuala TRUE if the tuple space has the given key, the formula FALSE otherwise

hasSpace

public Formula hasSpace(String id)

Formula to check whether a space exists

Parameters:

id - the space id

Returns:

returns formuala TRUE if the tuple space exists, the formula FALSE otherwise

getSpaceList

public ListTerm getSpaceList()

Return a list of the spaces that the agent has joined.

Returns:

returns an ASTRA list of tuple space ids