Provider (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

java.lang.Object
  java.util.Dictionary<K,V>
      java.util.Hashtable<Object,Object>
          java.util.Properties
              java.security.Provider

All Implemented Interfaces:: Serializable, Cloneable, Map<Object,Object>

Direct Known Subclasses:: AuthProvider

public abstract class Provider
extends Properties
extends Properties

This class represents a "provider" for the Java Security API, where a provider implements some or all parts of Java Security. Services that a provider may implement include:

Algorithms (such as DSA, RSA, MD5 or SHA-1).
Key generation, conversion, and management facilities (such as for algorithm-specific keys).

Each provider has a name and a version number, and is configured in each runtime it is installed in.

See The Provider Class in the "Java Cryptography Architecture API Specification & Reference" for information about how a particular type of provider, the cryptographic service provider, works and is installed. However, please note that a provider can be used to implement any security service in Java that uses a pluggable architecture with a choice of implementations that fit underneath.

Some provider implementations may encounter unrecoverable internal errors during their operation, for example a failure to communicate with a security token. A ProviderException should be used to indicate such errors.

The service type Provider is reserved for use by the security framework. Services of this type cannot be added, removed, or modified by applications. The following attributes are automatically placed in each Provider object:

Name Value
Provider.id name String.valueOf(provider.getName())
Provider.id version String.valueOf(provider.getVersion())
Provider.id info String.valueOf(provider.getInfo())
Provider.id className provider.getClass().getName()

Name	Value
`Provider.id name`	`String.valueOf(provider.getName())`
`Provider.id version`	`String.valueOf(provider.getVersion())`
`Provider.id info`	`String.valueOf(provider.getInfo())`
`Provider.id className`	`provider.getClass().getName()`

See Also:: Serialized Form

Nested Class Summary

static class Provider.Service
          The description of a security service.

Field Summary

Fields inherited from class java.util.Properties

defaults

Constructor Summary

protected Provider(String name, double version, String info)
          Constructs a provider with the specified name, version number, and information.

Method Summary

void clear()
          Clears this provider so that it no longer contains the properties used to look up facilities implemented by the provider.

Set<Map.Entry<Object,Object>> entrySet()
          Returns an unmodifiable Set view of the property entries contained in this Provider.

String getInfo()
          Returns a human-readable description of the provider and its services.

String getName()
          Returns the name of this provider.

Provider.Service getService(String type, String algorithm)
          Get the service describing this Provider's implementation of the specified type of this algorithm or alias.

Set<Provider.Service> getServices()
          Get an unmodifiable Set of all services supported by this Provider.

double getVersion()
          Returns the version number for this provider.

Set<Object> keySet()
          Returns an unmodifiable Set view of the property keys contained in this provider.

void load(InputStream inStream)
          Reads a property list (key and element pairs) from the input stream.

Object put(Object key, Object value)
          Sets the key property to have the specified value.

void putAll(Map<?,?> t)
          Copies all of the mappings from the specified Map to this provider.

protected void putService(Provider.Service s)
          Add a service.

Object remove(Object key)
          Removes the key property (and its corresponding value).

protected void removeService(Provider.Service s)
          Remove a service previously added using putService().

String toString()
          Returns a string with the name and the version number of this provider.

Collection<Object> values()
          Returns an unmodifiable Collection view of the property values contained in this provider.

Methods inherited from class java.util.Properties

getProperty, getProperty, list, list, loadFromXML, propertyNames, save, setProperty, store, storeToXML, storeToXML

Methods inherited from class java.util.Hashtable

clone, contains, containsKey, containsValue, elements, equals, get, hashCode, isEmpty, keys, rehash, size

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Nested Class Summary
`static class`	`Provider.Service` The description of a security service.

Fields inherited from class java.util.Properties
`defaults`

Constructor Summary
`protected`	`Provider(String name, double version, String info)` Constructs a provider with the specified name, version number, and information.

Method Summary
`void`	`clear()` Clears this provider so that it no longer contains the properties used to look up facilities implemented by the provider.
`Set<Map.Entry<Object,Object>>`	`entrySet()` Returns an unmodifiable Set view of the property entries contained in this Provider.
`String`	`getInfo()` Returns a human-readable description of the provider and its services.
`String`	`getName()` Returns the name of this provider.
`Provider.Service`	`getService(String type, String algorithm)` Get the service describing this Provider's implementation of the specified type of this algorithm or alias.
`Set<Provider.Service>`	`getServices()` Get an unmodifiable Set of all services supported by this Provider.
`double`	`getVersion()` Returns the version number for this provider.
`Set<Object>`	`keySet()` Returns an unmodifiable Set view of the property keys contained in this provider.
`void`	`load(InputStream inStream)` Reads a property list (key and element pairs) from the input stream.
`Object`	`put(Object key, Object value)` Sets the `key` property to have the specified `value`.
`void`	`putAll(Map<?,?> t)` Copies all of the mappings from the specified Map to this provider.
`protected void`	`putService(Provider.Service s)` Add a service.
`Object`	`remove(Object key)` Removes the `key` property (and its corresponding `value`).
`protected void`	`removeService(Provider.Service s)` Remove a service previously added using `putService()`.
`String`	`toString()` Returns a string with the name and the version number of this provider.
`Collection<Object>`	`values()` Returns an unmodifiable Collection view of the property values contained in this provider.

Methods inherited from class java.util.Properties
`getProperty, getProperty, list, list, loadFromXML, propertyNames, save, setProperty, store, storeToXML, storeToXML`

Methods inherited from class java.util.Hashtable
`clone, contains, containsKey, containsValue, elements, equals, get, hashCode, isEmpty, keys, rehash, size`

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

Constructor Detail

Provider

protected Provider(String name,
                   double version,
                   String info)

Constructs a provider with the specified name, version number, and information.

Parameters:: name - the provider name.; version - the provider version number.; info - a description of the provider and its services.

Method Detail

getName

public String getName()

Returns the name of this provider.

Returns:: the name of this provider.

getVersion

public double getVersion()

Returns the version number for this provider.

Returns:: the version number for this provider.

getInfo

public String getInfo()

Returns a human-readable description of the provider and its services. This may return an HTML page, with relevant links.

Returns:: a description of the provider and its services.

toString

public String toString()

Returns a string with the name and the version number of this provider.

Overrides:: toString in class Hashtable<Object,Object>

Returns:: the string with the name and the version number for this provider.

clear

public void clear()

Clears this provider so that it no longer contains the properties used to look up facilities implemented by the provider.

First, if there is a security manager, its checkSecurityAccess method is called with the string "clearProviderProperties."+name (where name is the provider name) to see if it's ok to clear this provider. If the default implementation of checkSecurityAccess is used (that is, that method is not overriden), then this results in a call to the security manager's checkPermission method with a SecurityPermission("clearProviderProperties."+name) permission.

Specified by:: clear in interface Map<Object,Object>
Overrides:: clear in class Hashtable<Object,Object>

Throws:: SecurityException - if a security manager exists and its SecurityManager.checkSecurityAccess(java.lang.String) method denies access to clear this provider
Since:: 1.2

load

public void load(InputStream inStream)
          throws IOException

Reads a property list (key and element pairs) from the input stream.

Overrides:: load in class Properties

Parameters:: inStream - the input stream.
Throws:: IOException - if an error occurred when reading from the input stream.
See Also:: Properties.load(java.io.InputStream)

putAll

public void putAll(Map<?,?> t)

Copies all of the mappings from the specified Map to this provider. These mappings will replace any properties that this provider had for any of the keys currently in the specified Map.

Specified by:: putAll in interface Map<Object,Object>
Overrides:: putAll in class Hashtable<Object,Object>

Parameters:: t - Mappings to be stored in this map.
Since:: 1.2

entrySet

public Set<Map.Entry<Object,Object>> entrySet()

Returns an unmodifiable Set view of the property entries contained in this Provider.

Specified by:: entrySet in interface Map<Object,Object>
Overrides:: entrySet in class Hashtable<Object,Object>

Returns:: a set view of the mappings contained in this map.
Since:: 1.2
See Also:: Map.Entry

keySet

public Set<Object> keySet()

Returns an unmodifiable Set view of the property keys contained in this provider.

Specified by:: keySet in interface Map<Object,Object>
Overrides:: keySet in class Hashtable<Object,Object>

Returns:: a set view of the keys contained in this map.
Since:: 1.2

values

public Collection<Object> values()

Returns an unmodifiable Collection view of the property values contained in this provider.

Specified by:: values in interface Map<Object,Object>
Overrides:: values in class Hashtable<Object,Object>

Returns:: a collection view of the values contained in this map.
Since:: 1.2

put

public Object put(Object key,
                  Object value)

Sets the key property to have the specified value.

First, if there is a security manager, its checkSecurityAccess method is called with the string "putProviderProperty."+name, where name is the provider name, to see if it's ok to set this provider's property values. If the default implementation of checkSecurityAccess is used (that is, that method is not overriden), then this results in a call to the security manager's checkPermission method with a SecurityPermission("putProviderProperty."+name) permission.

Specified by:: put in interface Map<Object,Object>
Overrides:: put in class Hashtable<Object,Object>

Parameters:: key - the property key.; value - the property value.
Returns:: the previous value of the specified property (key), or null if it did not have one.
Throws:: SecurityException - if a security manager exists and its SecurityManager.checkSecurityAccess(java.lang.String) method denies access to set property values.
Since:: 1.2
See Also:: Object.equals(Object), Hashtable.get(Object)

remove

public Object remove(Object key)

Removes the key property (and its corresponding value).

First, if there is a security manager, its checkSecurityAccess method is called with the string "removeProviderProperty."+name, where name is the provider name, to see if it's ok to remove this provider's properties. If the default implementation of checkSecurityAccess is used (that is, that method is not overriden), then this results in a call to the security manager's checkPermission method with a SecurityPermission("removeProviderProperty."+name) permission.

Specified by:: remove in interface Map<Object,Object>
Overrides:: remove in class Hashtable<Object,Object>

Parameters:: key - the key for the property to be removed.
Returns:: the value to which the key had been mapped, or null if the key did not have a mapping.
Throws:: SecurityException - if a security manager exists and its SecurityManager.checkSecurityAccess(java.lang.String) method denies access to remove this provider's properties.
Since:: 1.2

getService

public Provider.Service getService(String type,
                                   String algorithm)

Get the service describing this Provider's implementation of the specified type of this algorithm or alias. If no such implementation exists, this method returns null. If there are two matching services, one added to this provider using putService() and one added via put(), the service added via putService() is returned.

Parameters:: type - the type of service requested (for example, MessageDigest); algorithm - the case insensitive algorithm name (or alternate alias) of the service requested (for example, SHA-1)
Returns:: the service describing this Provider's matching service or null if no such service exists
Throws:: NullPointerException - if type or algorithm is null
Since:: 1.5

getServices

public Set<Provider.Service> getServices()

Get an unmodifiable Set of all services supported by this Provider.

Returns:: an unmodifiable Set of all services supported by this Provider
Since:: 1.5

putService

protected void putService(Provider.Service s)

Add a service. If a service of the same type with the same algorithm name exists and it was added using putService(), it is replaced by the new service. This method also places information about this service in the provider's Hashtable values in the format described in the Java Cryptography Architecture API Specification & Reference .

Also, if there is a security manager, its checkSecurityAccess method is called with the string "putProviderProperty."+name, where name is the provider name, to see if it's ok to set this provider's property values. If the default implementation of checkSecurityAccess is used (that is, that method is not overriden), then this results in a call to the security manager's checkPermission method with a SecurityPermission("putProviderProperty."+name) permission.

Parameters:: s - the Service to add
Throws:: SecurityException - if a security manager exists and its SecurityManager.checkSecurityAccess(java.lang.String) method denies access to set property values.; NullPointerException - if s is null
Since:: 1.5

removeService

protected void removeService(Provider.Service s)

Remove a service previously added using putService(). The specified service is removed from this provider. It will no longer be returned by getService() and its information will be removed from this provider's Hashtable.

Also, if there is a security manager, its checkSecurityAccess method is called with the string "removeProviderProperty."+name, where name is the provider name, to see if it's ok to remove this provider's properties. If the default implementation of checkSecurityAccess is used (that is, that method is not overriden), then this results in a call to the security manager's checkPermission method with a SecurityPermission("removeProviderProperty."+name) permission.

Parameters:: s - the Service to be removed
Throws:: SecurityException - if a security manager exists and its SecurityManager.checkSecurityAccess(java.lang.String) method denies access to remove this provider's properties.; NullPointerException - if s is null
Since:: 1.5