Provider

public abstract class Provider 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:

NameValue
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()

Nested Class Summary

class Provider.Service The description of a security service. 

Inherited Field Summary

Protected Constructor Summary

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

Public Method Summary

synchronized void
clear()
Clears this provider so that it no longer contains the properties used to look up facilities implemented by the provider.
Enumeration<Object>
elements()
Returns an enumeration of the values in this hashtable.
synchronized Set<Entry<ObjectObject>>
entrySet()
Returns an unmodifiable Set view of the property entries contained in this Provider.
synchronized void
forEach(BiConsumer<? super Object, ? super Object> action)
Performs the given action for each entry in this map until all entries have been processed or the action throws an exception.
Object
get(Object key)
Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.
String
getInfo()
Returns a human-readable description of the provider and its services.
String
getName()
Returns the name of this provider.
String
getProperty(String key)
Searches for the property with the specified key in this property list.
synchronized Provider.Service
getService(String type, String algorithm)
Get the service describing this Provider's implementation of the specified type of this algorithm or alias.
synchronized 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.
Enumeration<Object>
keys()
Returns an enumeration of the keys in this hashtable.
synchronized void
load(InputStream inStream)
Reads a property list (key and element pairs) from the input stream.
synchronized Object
put(Object key, Object value)
Sets the key property to have the specified value.
synchronized void
putAll(Map<?, ?> t)
Copies all of the mappings from the specified Map to this provider.
synchronized Object
remove(Object key)
Removes the key property (and its corresponding value).
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.

Protected Method Summary

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

Inherited Method Summary

Protected Constructors

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.

Public Methods

public synchronized 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.

Throws
SecurityException if a security manager exists and its checkSecurityAccess(String) method denies access to clear this provider

public Enumeration<Object> elements ()

Returns an enumeration of the values in this hashtable. Use the Enumeration methods on the returned object to fetch the elements sequentially.

Returns
  • an enumeration of the values in this hashtable.

public synchronized Set<Entry<ObjectObject>> entrySet ()

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

Returns
  • a set view of the mappings contained in this map
See Also

public synchronized void forEach (BiConsumer<? super Object, ? super Object> action)

Performs the given action for each entry in this map until all entries have been processed or the action throws an exception. Unless otherwise specified by the implementing class, actions are performed in the order of entry set iteration (if an iteration order is specified.) Exceptions thrown by the action are relayed to the caller.

Parameters
action The action to be performed for each entry

public Object get (Object key)

Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.

More formally, if this map contains a mapping from a key k to a value v such that (key.equals(k)), then this method returns v; otherwise it returns null. (There can be at most one such mapping.)

Parameters
key the key whose associated value is to be returned
Returns
  • the value to which the specified key is mapped, or null if this map contains no mapping for the key

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.

public String getName ()

Returns the name of this provider.

Returns
  • the name of this provider.

public String getProperty (String key)

Searches for the property with the specified key in this property list. If the key is not found in this property list, the default property list, and its defaults, recursively, are then checked. The method returns null if the property is not found.

Parameters
key the property key.
Returns
  • the value in this property list with the specified key value.

public synchronized 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

public synchronized 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

public double getVersion ()

Returns the version number for this provider.

Returns
  • the version number for this provider.

public Set<Object> keySet ()

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

Returns
  • a set view of the keys contained in this map

public Enumeration<Object> keys ()

Returns an enumeration of the keys in this hashtable.

Returns
  • an enumeration of the keys in this hashtable.

public synchronized void load (InputStream inStream)

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

Parameters
inStream the input stream.
Throws
IOException if an error occurred when reading from the input stream.

public synchronized 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.

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 checkSecurityAccess(String) method denies access to set property values.

public synchronized 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.

Parameters
t mappings to be stored in this map

public synchronized 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.

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 checkSecurityAccess(String) method denies access to remove this provider's properties.

public String toString ()

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

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

public Collection<Object> values ()

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

Returns
  • a collection view of the values contained in this map

Protected Methods

protected synchronized 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 checkSecurityAccess(String) method denies access to set property values.
NullPointerException if s is null

protected synchronized 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 checkSecurityAccess(String) method denies access to remove this provider's properties.
NullPointerException if s is null