Provider.Service (Java 2 Platform SE 5.0) - JDK 5 Documentation v1.5.0, Java 2 SDK 英文文档

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Java^TM 2 Platform
Standard Ed. 5.0

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java.security
Class Provider.Service

java.lang.Object
  java.security.Provider.Service

Enclosing class:: Provider

public static class Provider.Service
extends Object
extends Object

The description of a security service. It encapsulates the properties of a service and contains a factory method to obtain new implementation instances of this service.

Each service has a provider that offers the service, a type, an algorithm name, and the name of the class that implements the service. Optionally, it also includes a list of alternate algorithm names for this service (aliases) and attributes, which are a map of (name, value) String pairs.

This class defines the methods supportsParameter() and newInstance() which are used by the Java security framework when it searches for suitable services and instantes them. The valid arguments to those methods depend on the type of service. For the service types defined within J2SE, see the Java Cryptography Architecture API Specification & Reference for the valid values. Note that components outside of J2SE can define additional types of services and their behavior.

Instances of this class are immutable.

Since:: 1.5

Constructor Summary

Provider.Service(Provider provider, String type, String algorithm, String className, List<String> aliases, Map<String,String> attributes)
          Construct a new service.

Method Summary

String getAlgorithm()
          Return the name of the algorithm of this service.

String getAttribute(String name)
          Return the value of the specified attribute or null if this attribute is not set for this Service.

String getClassName()
          Return the name of the class implementing this service.

Provider getProvider()
          Return the Provider of this service.

String getType()
          Get the type of this service.

Object newInstance(Object constructorParameter)
          Return a new instance of the implementation described by this service.

boolean supportsParameter(Object parameter)
          Test whether this Service can use the specified parameter.

String toString()
          Return a String representation of this service.

Methods inherited from class java.lang.Object

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

Constructor Summary
`Provider.Service(Provider provider, String type, String algorithm, String className, List<String> aliases, Map<String,String> attributes)` Construct a new service.

Method Summary
`String`	`getAlgorithm()` Return the name of the algorithm of this service.
`String`	`getAttribute(String name)` Return the value of the specified attribute or null if this attribute is not set for this Service.
`String`	`getClassName()` Return the name of the class implementing this service.
`Provider`	`getProvider()` Return the Provider of this service.
`String`	`getType()` Get the type of this service.
`Object`	`newInstance(Object constructorParameter)` Return a new instance of the implementation described by this service.
`boolean`	`supportsParameter(Object parameter)` Test whether this Service can use the specified parameter.
`String`	`toString()` Return a String representation of this service.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Constructor Detail

Provider.Service

public Provider.Service(Provider provider,
                        String type,
                        String algorithm,
                        String className,
                        List<String> aliases,
                        Map<String,String> attributes)

Construct a new service.

Parameters:: provider - the provider that offers this service; type - the type of this service; algorithm - the algorithm name; className - the name of the class implementing this service; aliases - List of aliases or null if algorithm has no aliases; attributes - Map of attributes or null if this implementation has no attributes
Throws:: NullPointerException - if provider, type, algorithm, or className is null

Method Detail

getType

public final String getType()

Get the type of this service. For example, MessageDigest.

Returns:: the type of this service

getAlgorithm

public final String getAlgorithm()

Return the name of the algorithm of this service. For example, SHA-1.

Returns:: the algorithm of this service

getProvider

public final Provider getProvider()

Return the Provider of this service.

Returns:: the Provider of this service

getClassName

public final String getClassName()

Return the name of the class implementing this service.

Returns:: the name of the class implementing this service

getAttribute

public final String getAttribute(String name)

Return the value of the specified attribute or null if this attribute is not set for this Service.

Parameters:: name - the name of the requested attribute
Returns:: the value of the specified attribute or null if the attribute is not present
Throws:: NullPointerException - if name is null

newInstance

public Object newInstance(Object constructorParameter)
                   throws NoSuchAlgorithmException

Return a new instance of the implementation described by this service. The security provider framework uses this method to construct implementations. Applications will typically not need to call it.

The default implementation uses reflection to invoke the standard constructor for this type of service. Security providers can override this method to implement instantiation in a different way. For details and the values of constructorParameter that are valid for the various types of services see the Java Cryptography Architecture API Specification & Reference.

Parameters:: constructorParameter - the value to pass to the constructor, or null if this type of service does not use a constructorParameter.
Returns:: a new implementation of this service
Throws:: InvalidParameterException - if the value of constructorParameter is invalid for this type of service.; NoSuchAlgorithmException - if instantation failed for any other reason.

supportsParameter

public boolean supportsParameter(Object parameter)

Test whether this Service can use the specified parameter. Returns false if this service cannot use the parameter. Returns true if this service can use the parameter, if a fast test is infeasible, or if the status is unknown.

The security provider framework uses this method with some types of services to quickly exclude non-matching implementations for consideration. Applications will typically not need to call it.

For details and the values of parameter that are valid for the various types of services see the top of this class and the Java Cryptography Architecture API Specification & Reference. Security providers can override it to implement their own test.

Parameters:: parameter - the parameter to test
Returns:: false if this this service cannot use the specified parameter; true if it can possibly use the parameter
Throws:: InvalidParameterException - if the value of parameter is invalid for this type of service or if this method cannot be used with this type of service

toString

public String toString()

Return a String representation of this service.

Overrides:: toString in class Object

Returns:: a String representation of this service.