Class CardTerminals

java.lang.Object

javax.smartcardio.CardTerminals

public abstract class CardTerminals
extends Object

The set of terminals supported by a TerminalFactory. This class allows applications to enumerate the available CardTerminals, obtain a specific CardTerminal, or wait for the insertion or removal of cards.

This class is multi-threading safe and can be used by multiple threads concurrently. However, this object keeps track of the card presence state of each of its terminals. Multiple objects should be used if independent calls to waitForChange() are required.

Applications can obtain instances of this class by calling TerminalFactory.terminals().

Since:

1.6

See Also:

• TerminalFactory
• CardTerminal

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	CardTerminals.State	Enumeration of attributes of a CardTerminal.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	CardTerminals()	Constructs a new CardTerminals object.

Method Summary

Modifier and Type	Method	Description
CardTerminal	getTerminal(String name)	Returns the terminal with the specified name or null if no such terminal exists.
List<CardTerminal>	list()	Returns an unmodifiable list of all available terminals.
abstract List<CardTerminal>	list(CardTerminals.State state)	Returns an unmodifiable list of all terminals matching the specified state.
void	waitForChange()	Waits for card insertion or removal in any of the terminals of this object.
abstract boolean	waitForChange(long timeout)	Waits for card insertion or removal in any of the terminals of this object or until the timeout expires.

Methods declared in class Object

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

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Constructor Details

CardTerminals

protected CardTerminals()

Constructs a new CardTerminals object.

This constructor is called by subclasses only. Application should call TerminalFactory.terminals() to obtain a CardTerminals object.

Method Details

list

public List<CardTerminal> list()
                        throws CardException

Returns an unmodifiable list of all available terminals.

Returns:

an unmodifiable list of all available terminals.

Throws:

CardException - if the card operation failed

list

public abstract List<CardTerminal> list(CardTerminals.State state)
                                 throws CardException

Returns an unmodifiable list of all terminals matching the specified state.

If state is State.ALL, this method returns all CardTerminals encapsulated by this object. If state is State.CARD_PRESENT or State.CARD_ABSENT, it returns all CardTerminals where a card is currently present or absent, respectively.

If state is State.CARD_INSERTION or State.CARD_REMOVAL, it returns all CardTerminals for which an insertion (or removal, respectively) was detected during the last call to waitForChange(). If waitForChange() has not been called on this object, CARD_INSERTION is equivalent to CARD_PRESENT and CARD_REMOVAL is equivalent to CARD_ABSENT. For an example of the use of CARD_INSERTION, see waitForChange().

Parameters:

state - the State

Returns:

an unmodifiable list of all terminals matching the specified state.

Throws:

NullPointerException - if state is null

CardException - if the card operation failed

getTerminal

public CardTerminal getTerminal(String name)

Returns the terminal with the specified name or null if no such terminal exists.

Parameters:

name - the terminal name

Returns:

the terminal with the specified name or null if no such terminal exists.

Throws:

NullPointerException - if name is null

waitForChange

public void waitForChange()
                   throws CardException

Waits for card insertion or removal in any of the terminals of this object.

This call is equivalent to calling waitForChange(0).

Throws:

IllegalStateException - if this CardTerminals object does not contain any terminals

CardException - if the card operation failed

waitForChange

public abstract boolean waitForChange(long timeout)
                               throws CardException

Waits for card insertion or removal in any of the terminals of this object or until the timeout expires.

This method examines each CardTerminal of this object. If a card was inserted into or removed from a CardTerminal since the previous call to waitForChange(), it returns immediately. Otherwise, or if this is the first call to waitForChange() on this object, it blocks until a card is inserted into or removed from a CardTerminal.

If timeout is greater than 0, the method returns after timeout milliseconds even if there is no change in state. In that case, this method returns false; otherwise it returns true.

This method is often used in a loop in combination with list(State.CARD_INSERTION), for example:

 TerminalFactory factory = ...;
 CardTerminals terminals = factory.terminals();
 while (true) {
     for (CardTerminal terminal : terminals.list(CARD_INSERTION)) {
         // examine Card in terminal, return if it matches
     }
     terminals.waitForChange();
 }

Parameters:

timeout - if positive, block for up to timeout milliseconds; if zero, block indefinitely; must not be negative

Returns:

false if the method returns due to an expired timeout, true otherwise.

Throws:

IllegalStateException - if this CardTerminals object does not contain any terminals

IllegalArgumentException - if timeout is negative

CardException - if the card operation failed