Provider

public abstract class Provider
extends Properties

java.lang.Object
   ↳ java.util.Dictionary<java.lang.Objectjava.lang.Object>
     ↳ java.util.Hashtable<java.lang.Objectjava.lang.Object>
       ↳ java.util.Properties
         ↳ java.security.Provider


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:

Attributes Automatically Placed in a 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()

Summary

Nested classes

class Provider.Service

The description of a security service. 

Inherited fields

Protected constructors

Provider(String name, double version, String info)

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

Public methods

void clear()

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

Object compute(Object key, BiFunction<? super Object, ? super Object, ?> remappingFunction)

Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping).

Object computeIfAbsent(Object key, Function<? super Object, ?> mappingFunction)

If the specified key is not already associated with a value (or is mapped to null), attempts to compute its value using the given mapping function and enters it into this map unless null.

Object computeIfPresent(Object key, BiFunction<? super Object, ? super Object, ?> remappingFunction)

If the value for the specified key is present and non-null, attempts to compute a new mapping given the key and its current mapped value.

Enumeration<Object> elements()

Returns an enumeration of the values in this hashtable.

Set<Entry<ObjectObject>> entrySet()

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

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.

Object getOrDefault(Object key, Object defaultValue)

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

String getProperty(String key)

Searches for the property with the specified key in this property list.

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.

Enumeration<Object> keys()

Returns an enumeration of the keys in this hashtable.

void load(InputStream inStream)

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

Object merge(Object key, Object value, BiFunction<? super Object, ? super Object, ?> remappingFunction)

If the specified key is not already associated with a value or is associated with null, associates it with the given value.

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.

Object putIfAbsent(Object key, Object value)

If the specified key is not already associated with a value (or is mapped to null) associates it with the given value and returns null, else returns the current value.

boolean remove(Object key, Object value)

Removes the entry for the specified key only if it is currently mapped to the specified value.

Object remove(Object key)

Removes the key property (and its corresponding value).

Object replace(Object key, Object value)

Replaces the entry for the specified key only if it is currently mapped to some value.

boolean replace(Object key, Object oldValue, Object newValue)

Replaces the entry for the specified key only if currently mapped to the specified value.

void replaceAll(BiFunction<? super Object, ? super Object, ?> function)

Replaces each entry's value with the result of invoking the given function on that entry, in the order entries are returned by an entry set iterator, until all entries have been processed or the function throws an exception.

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 methods

void putService(Provider.Service s)

Add a service.

void removeService(Provider.Service s)

Remove a service previously added using putService().

Inherited methods

Protected constructors

Provider

Added in API level 1
protected Provider (String name, 
                double version, 
                String info)

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

Parameters
name String: the provider name.

version double: the provider version number.

info String: a description of the provider and its services.

Public methods

clear

Added in API level 1
public void clear ()

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

If a security manager is enabled, 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.

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

compute

Added in API level 24
public Object compute (Object key, 
                BiFunction<? super Object, ? super Object, ?> remappingFunction)

Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping).

If a security manager is enabled, its checkSecurityAccess method is called with the strings "putProviderProperty."+name and "removeProviderProperty."+name, where name is the provider name, to see if it's ok to set this provider's property values and remove this provider's properties.

Parameters
key Object: key with which the specified value is to be associated

remappingFunction BiFunction: the remapping function to compute a value

Returns
Object the new value associated with the specified key, or null if none

Throws
SecurityException if a security manager exists and its SecurityManager.checkSecurityAccess(String) method denies access to set property values or remove properties.

computeIfAbsent

Added in API level 24
public Object computeIfAbsent (Object key, 
                Function<? super Object, ?> mappingFunction)

If the specified key is not already associated with a value (or is mapped to null), attempts to compute its value using the given mapping function and enters it into this map unless null.

If a security manager is enabled, its checkSecurityAccess method is called with the strings "putProviderProperty."+name and "removeProviderProperty."+name, where name is the provider name, to see if it's ok to set this provider's property values and remove this provider's properties.

Parameters
key Object: key with which the specified value is to be associated

mappingFunction Function: the mapping function to compute a value

Returns
Object the current (existing or computed) value associated with the specified key, or null if the computed value is null

Throws
SecurityException if a security manager exists and its SecurityManager.checkSecurityAccess(String) method denies access to set property values and remove properties.

computeIfPresent

Added in API level 24
public Object computeIfPresent (Object key, 
                BiFunction<? super Object, ? super Object, ?> remappingFunction)

If the value for the specified key is present and non-null, attempts to compute a new mapping given the key and its current mapped value.

If a security manager is enabled, its checkSecurityAccess method is called with the strings "putProviderProperty."+name and "removeProviderProperty."+name, where name is the provider name, to see if it's ok to set this provider's property values and remove this provider's properties.

Parameters
key Object: key with which the specified value is to be associated

remappingFunction BiFunction: the remapping function to compute a value

Returns
Object the new value associated with the specified key, or null if none

Throws
SecurityException if a security manager exists and its SecurityManager.checkSecurityAccess(String) method denies access to set property values or remove properties.

elements

Added in API level 1
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. If the hashtable is structurally modified while enumerating over the values then the results of enumerating are undefined.

Returns
Enumeration<Object> an enumeration of the values in this hashtable.

entrySet

Added in API level 1
public Set<Entry<ObjectObject>> entrySet ()

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

Returns
Set<Entry<ObjectObject>> a set view of the mappings contained in this map

See also:

forEach

Added in API level 24
public 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 BiConsumer: The action to be performed for each entry

get

Added in API level 1
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 Object: the key whose associated value is to be returned

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

getInfo

Added in API level 1
public String getInfo ()

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

Returns
String a description of the provider and its services.

getName

Added in API level 1
public String getName ()

Returns the name of this provider.

Returns
String the name of this provider.

getOrDefault

Added in API level 24
public Object getOrDefault (Object key, 
                Object defaultValue)

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

Parameters
key Object: the key whose associated value is to be returned

defaultValue Object: the default mapping of the key

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

getProperty

Added in API level 1
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 String: the property key.

Returns
String the value in this property list with the specified key value.

getService

Added in API level 1
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 String: the type of service requested (for example, MessageDigest)

algorithm String: the case insensitive algorithm name (or alternate alias) of the service requested (for example, SHA-1)

Returns
Provider.Service the service describing this Provider's matching service or null if no such service exists

Throws
NullPointerException if type or algorithm is null

getServices

Added in API level 1
public Set<Provider.Service> getServices ()

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

Returns
Set<Provider.Service> an unmodifiable Set of all services supported by this Provider

getVersion

Added in API level 1
public double getVersion ()

Returns the version number for this provider.

Returns
double the version number for this provider.

keySet

Added in API level 1
public Set<Object> keySet ()

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

Returns
Set<Object> a set view of the keys contained in this map

keys

Added in API level 1
public Enumeration<Object> keys ()

Returns an enumeration of the keys in this hashtable. Use the Enumeration methods on the returned object to fetch the keys sequentially. If the hashtable is structurally modified while enumerating over the keys then the results of enumerating are undefined.

Returns
Enumeration<Object> an enumeration of the keys in this hashtable.

load

Added in API level 1
public void load (InputStream inStream)

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

Parameters
inStream InputStream: the input stream.

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

merge

Added in API level 24
public Object merge (Object key, 
                Object value, 
                BiFunction<? super Object, ? super Object, ?> remappingFunction)

If the specified key is not already associated with a value or is associated with null, associates it with the given value. Otherwise, replaces the value with the results of the given remapping function, or removes if the result is null. This method may be of use when combining multiple mapped values for a key.

If a security manager is enabled, its checkSecurityAccess method is called with the strings "putProviderProperty."+name and "removeProviderProperty."+name, where name is the provider name, to see if it's ok to set this provider's property values and remove this provider's properties.

Parameters
key Object: key with which the resulting value is to be associated

value Object: the non-null value to be merged with the existing value associated with the key or, if no existing value or a null value is associated with the key, to be associated with the key

remappingFunction BiFunction: the remapping function to recompute a value if present

Returns
Object the new value associated with the specified key, or null if no value is associated with the key

Throws
SecurityException if a security manager exists and its SecurityManager.checkSecurityAccess(String) method denies access to set property values or remove properties.

put

Added in API level 1
public Object put (Object key, 
                Object value)

Sets the key property to have the specified value.

If a security manager is enabled, 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.

Parameters
key Object: the hashtable key

value Object: the value

Returns
Object the previous value of the specified key in this hashtable, or null if it did not have one

Throws
SecurityException if a security manager exists and its SecurityManager.checkSecurityAccess(String) method denies access to set property values.

putAll

Added in API level 1
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.

Parameters
t Map: mappings to be stored in this map

putIfAbsent

Added in API level 24
public Object putIfAbsent (Object key, 
                Object value)

If the specified key is not already associated with a value (or is mapped to null) associates it with the given value and returns null, else returns the current value.

If a security manager is enabled, 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.

Parameters
key Object: key with which the specified value is to be associated

value Object: value to be associated with the specified key

Returns
Object the previous value associated with the specified key, or null if there was no mapping for the key. (A null return can also indicate that the map previously associated null with the key, if the implementation supports null values.)

Throws
SecurityException if a security manager exists and its SecurityManager.checkSecurityAccess(String) method denies access to set property values.

remove

Added in API level 24
public boolean remove (Object key, 
                Object value)

Removes the entry for the specified key only if it is currently mapped to the specified value.

If a security manager is enabled, 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.

Parameters
key Object: key with which the specified value is associated

value Object: value expected to be associated with the specified key

Returns
boolean true if the value was removed

Throws
SecurityException if a security manager exists and its SecurityManager.checkSecurityAccess(String) method denies access to remove this provider's properties.

remove

Added in API level 1
public Object remove (Object key)

Removes the key property (and its corresponding value).

If a security manager is enabled, 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.

Parameters
key Object: the key that needs to be removed

Returns
Object the value to which the key had been mapped in this hashtable, or null if the key did not have a mapping

Throws
SecurityException if a security manager exists and its SecurityManager.checkSecurityAccess(String) method denies access to remove this provider's properties.

replace

Added in API level 24
public Object replace (Object key, 
                Object value)

Replaces the entry for the specified key only if it is currently mapped to some value.

If a security manager is enabled, 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.

Parameters
key Object: key with which the specified value is associated

value Object: value to be associated with the specified key

Returns
Object the previous value associated with the specified key, or null if there was no mapping for the key. (A null return can also indicate that the map previously associated null with the key, if the implementation supports null values.)

Throws
SecurityException if a security manager exists and its SecurityManager.checkSecurityAccess(String) method denies access to set property values.

replace

Added in API level 24
public boolean replace (Object key, 
                Object oldValue, 
                Object newValue)

Replaces the entry for the specified key only if currently mapped to the specified value.

If a security manager is enabled, 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.

Parameters
key Object: key with which the specified value is associated

oldValue Object: value expected to be associated with the specified key

newValue Object: value to be associated with the specified key

Returns
boolean true if the value was replaced

Throws
SecurityException if a security manager exists and its SecurityManager.checkSecurityAccess(String) method denies access to set property values.

replaceAll

Added in API level 24
public void replaceAll (BiFunction<? super Object, ? super Object, ?> function)

Replaces each entry's value with the result of invoking the given function on that entry, in the order entries are returned by an entry set iterator, until all entries have been processed or the function throws an exception.

If a security manager is enabled, 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.

Parameters
function BiFunction: the function to apply to each entry

Throws
SecurityException if a security manager exists and its SecurityManager.checkSecurityAccess(String) method denies access to set property values.

toString

Added in API level 1
public String toString ()

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

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

values

Added in API level 1
public Collection<Object> values ()

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

Returns
Collection<Object> a collection view of the values contained in this map

Protected methods

putService

Added in API level 1
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 Provider.Service: the Service to add

Throws
SecurityException if a security manager exists and its SecurityManager.checkSecurityAccess(String) method denies access to set property values.
NullPointerException if s is null

removeService

Added in API level 1
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 Provider.Service: the Service to be removed

Throws
SecurityException if a security manager exists and its SecurityManager.checkSecurityAccess(String) method denies access to remove this provider's properties.
NullPointerException if s is null