public abstract class CardTerminals extends Object
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().
TerminalFactory
,
CardTerminal
Modifier and Type | Class and Description |
---|---|
static class |
CardTerminals.State
Enumeration of attributes of a CardTerminal.
|
Modifier | Constructor and Description |
---|---|
protected |
CardTerminals()
Constructs a new CardTerminals object.
|
Modifier and Type | Method and 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.
|
protected CardTerminals()
This constructor is called by subclasses only. Application should call TerminalFactory.terminals() to obtain a CardTerminals object.
public List<CardTerminal> list() throws CardException
CardException
- if the card operation failedpublic abstract List<CardTerminal> list(CardTerminals.State state) throws CardException
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()
.
state
- the StateNullPointerException
- if attr is nullCardException
- if the card operation failedpublic CardTerminal getTerminal(String name)
NullPointerException
- if name is nullpublic void waitForChange() throws CardException
This call is equivalent to calling waitForChange(0).
IllegalStateException
- if this CardTerminals
object does not contain any terminalsCardException
- if the card operation failedpublic abstract boolean waitForChange(long timeout) throws CardException
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(); }
timeout
- if positive, block for up to timeout
milliseconds; if zero, block indefinitely; must not be negativeIllegalStateException
- if this CardTerminals
object does not contain any terminalsIllegalArgumentException
- if timeout is negativeCardException
- if the card operation failed
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