javax.smartcardio
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

static class

CardTerminals.State Enumeration of attributes of a CardTerminal.

Constructor Summary

protected

CardTerminals() Constructs a new CardTerminals object.

Method Summary

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 inherited from class java.lang.Object

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

Constructor Detail

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 Detail

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 attribute.

Throws:

NullPointerException - if attr 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.

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