javax.print
abstract public class: PrintServiceLookup [javadoc |
source]
java.lang.Object
javax.print.PrintServiceLookup
Implementations of this class provide lookup services for
print services (typically equivalent to printers) of a particular type.
Multiple implementations may be installed concurrently.
All implementations must be able to describe the located printers
as instances of a PrintService.
Typically implementations of this service class are located
automatically in JAR files (see the SPI JAR file specification).
These classes must be instantiable using a default constructor.
Alternatively applications may explicitly register instances
at runtime.
Applications use only the static methods of this abstract class.
The instance methods are implemented by a service provider in a subclass
and the unification of the results from all installed lookup classes
are reported by the static methods of this class when called by
the application.
A PrintServiceLookup implementor is recommended to check for the
SecurityManager.checkPrintJobAccess() to deny access to untrusted code.
Following this recommended policy means that untrusted code may not
be able to locate any print services. Downloaded applets are the most
common example of untrusted code.
This check is made on a per lookup service basis to allow flexibility in
the policy to reflect the needs of different lookup services.
Services which are registered by registerService(PrintService)
will not be included in lookup results if a security manager is
installed and its checkPrintJobAccess() method denies access.
| Methods from java.lang.Object: |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Method from javax.print.PrintServiceLookup Detail: |
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 abstract public PrintService getDefaultPrintService()
Not called directly by applications.
Implemented by a service provider, and called by the print lookup
service |
abstract public MultiDocPrintService[] getMultiDocPrintServices(DocFlavor[] flavors,
AttributeSet attributes) Not called directly by applications.
Implemented by a service provider, used by the static methods
of this class.
Locates MultiDoc print services which can be positively confirmed
to support the combination of attributes and DocFlavors specified.
|
abstract public PrintService[] getPrintServices() Not called directly by applications.
Implemented by a service provider, used by the static methods
of this class. |
abstract public PrintService[] getPrintServices(DocFlavor flavor,
AttributeSet attributes) Locates services that can be positively confirmed to support
the combination of attributes and DocFlavors specified.
This method is not called directly by applications.
Implemented by a service provider, used by the static methods
of this class.
The results should be the same as obtaining all the PrintServices
and querying each one individually on its support for the
specified attributes and flavors, but the process can be more
efficient by taking advantage of the capabilities of lookup services
for the print services. |
 public static final PrintService lookupDefaultPrintService() {
Iterator psIterator = getAllLookupServices().iterator();
while (psIterator.hasNext()) {
try {
PrintServiceLookup lus = (PrintServiceLookup)psIterator.next();
PrintService service = lus.getDefaultPrintService();
if (service != null) {
return service;
}
} catch (Exception e) {
}
}
return null;
}
Locates the default print service for this environment.
This may return null.
If multiple lookup services each specify a default, the
chosen service is not precisely defined, but a
platform native service, rather than an installed service,
is usually returned as the default. If there is no clearly
identifiable
platform native default print service, the default is the first
to be located in an implementation-dependent manner.
This may include making use of any preferences API that is available
as part of the Java or native platform.
This algorithm may be overridden by a user setting the property
javax.print.defaultPrinter.
A service specified must be discovered to be valid and currently
available to be returned as the default. |
public static final MultiDocPrintService[] lookupMultiDocPrintServices(DocFlavor[] flavors,
AttributeSet attributes) {
ArrayList list = getMultiDocServices(flavors, attributes);
return (MultiDocPrintService[])
list.toArray(new MultiDocPrintService[list.size()]);
} Locates MultiDoc print Services capable of printing MultiDocs
containing all the specified doc flavors.
This method is useful to help locate a service that can print
a MultiDoc in which the elements may be different
flavors. An application could perform this itself by multiple lookups
on each DocFlavor in turn and collating the results,
but the lookup service may be able to do this more efficiently. |
public static final PrintService[] lookupPrintServices(DocFlavor flavor,
AttributeSet attributes) {
ArrayList list = getServices(flavor, attributes);
return (PrintService[])(list.toArray(new PrintService[list.size()]));
} Locates print services capable of printing the specified
DocFlavor . |
public static boolean registerService(PrintService service) {
synchronized (PrintServiceLookup.class) {
if (service instanceof StreamPrintService) {
return false;
}
ArrayList registeredServices = getRegisteredServices();
if (registeredServices == null) {
registeredServices = initRegisteredServices();
}
else {
if (registeredServices.contains(service)) {
return false;
}
}
registeredServices.add(service);
return true;
}
} Allows an application to directly register an instance of a
class which implements a print service.
The lookup operations for this service will be
performed by the PrintServiceLookup class using the attribute
values and classes reported by the service.
This may be less efficient than a lookup
service tuned for that service.
Therefore registering a PrintServiceLookup instance
instead is recommended.
The method returns true if this service is not previously
registered and is now successfully registered.
This method should not be called with StreamPrintService instances.
They will always fail to register and the method will return false. |
public static boolean registerServiceProvider(PrintServiceLookup sp) {
synchronized (PrintServiceLookup.class) {
Iterator psIterator = getAllLookupServices().iterator();
while (psIterator.hasNext()) {
try {
Object lus = psIterator.next();
if (lus.getClass() == sp.getClass()) {
return false;
}
} catch (Exception e) {
}
}
getListOfLookupServices().add(sp);
return true;
}
} Allows an application to explicitly register a class that
implements lookup services. The registration will not persist
across VM invocations.
This is useful if an application needs to make a new service
available that is not part of the installation.
If the lookup service is already registered, or cannot be registered,
the method returns false.
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