AlgorithmParameters (Java 2 Platform SE 5.0) (original) (raw)
java.security
Class AlgorithmParameters
java.lang.Object
java.security.AlgorithmParameters
public class AlgorithmParameters
extends Object
This class is used as an opaque representation of cryptographic parameters.
An AlgorithmParameters object for managing the parameters for a particular algorithm can be obtained by calling one of the getInstance factory methods (static methods that return instances of a given class).
There are two ways to request such an implementation: by specifying either just an algorithm name, or both an algorithm name and a package provider.
- If just an algorithm name is specified, the system will determine if there is an AlgorithmParameters implementation for the algorithm requested available in the environment, and if there is more than one, if there is a preferred one.
- If both an algorithm name and a package provider are specified, the system will determine if there is an implementation in the package requested, and throw an exception if there is not.
Once an AlgorithmParameters object is returned, it must be initialized via a call to init, using an appropriate parameter specification or parameter encoding.
A transparent parameter specification is obtained from anAlgorithmParameters object via a call togetParameterSpec, and a byte encoding of the parameters is obtained via a call to getEncoded.
Since:
1.2
See Also:
AlgorithmParameterSpec, DSAParameterSpec, KeyPairGenerator
| Constructor Summary | |
|---|---|
| protected | [AlgorithmParameters](../../java/security/AlgorithmParameters.html#AlgorithmParameters%28java.security.AlgorithmParametersSpi, java.security.Provider, java.lang.String%29)(AlgorithmParametersSpi paramSpi,Provider provider,String algorithm) Creates an AlgorithmParameters object. |
| Method Summary | |
|---|---|
| String | getAlgorithm() Returns the name of the algorithm associated with this parameter object. |
| byte[] | getEncoded() Returns the parameters in their primary encoding format. |
| byte[] | getEncoded(String format) Returns the parameters encoded in the specified scheme. |
| static AlgorithmParameters | getInstance(String algorithm) Generates a parameter object for the specified algorithm. |
| static AlgorithmParameters | [getInstance](../../java/security/AlgorithmParameters.html#getInstance%28java.lang.String, java.security.Provider%29)(String algorithm,Provider provider) Generates a parameter object for the specified algorithm, as supplied by the specified provider, if such an algorithm is available from the provider. |
| static AlgorithmParameters | [getInstance](../../java/security/AlgorithmParameters.html#getInstance%28java.lang.String, java.lang.String%29)(String algorithm,String provider) Generates a parameter object for the specified algorithm, as supplied by the specified provider, if such an algorithm is available from the provider. |
| <T extends AlgorithmParameterSpec> T | getParameterSpec(Class paramSpec) Returns a (transparent) specification of this parameter object. |
| Provider | getProvider() Returns the provider of this parameter object. |
| void | init(AlgorithmParameterSpec paramSpec) Initializes this parameter object using the parameters specified in paramSpec. |
| void | init(byte[] params) Imports the specified parameters and decodes them according to the primary decoding format for parameters. |
| void | [init](../../java/security/AlgorithmParameters.html#init%28byte[], java.lang.String%29)(byte[] params,String format) Imports the parameters from params and decodes them according to the specified decoding scheme. |
| String | toString() Returns a formatted string describing the parameters. |
| Methods inherited from class java.lang.Object |
|---|
| clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, [wait](../../java/lang/Object.html#wait%28long, int%29) |
| Constructor Detail |
|---|
AlgorithmParameters
protected AlgorithmParameters(AlgorithmParametersSpi paramSpi, Provider provider, String algorithm)
Creates an AlgorithmParameters object.
Parameters:
paramSpi - the delegate
provider - the provider
algorithm - the algorithm
| Method Detail |
|---|
getAlgorithm
public final String getAlgorithm()
Returns the name of the algorithm associated with this parameter object.
Returns:
the algorithm name.
getInstance
public static AlgorithmParameters getInstance(String algorithm) throws NoSuchAlgorithmException
Generates a parameter object for the specified algorithm.
If the default provider package provides an implementation of the requested algorithm, an instance of AlgorithmParameters containing that implementation is returned. If the algorithm is not available in the default package, other packages are searched.
The returned parameter object must be initialized via a call toinit, using an appropriate parameter specification or parameter encoding.
Parameters:
algorithm - the name of the algorithm requested.
Returns:
the new parameter object.
Throws:
[NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security") - if the algorithm is not available in the environment.
getInstance
public static AlgorithmParameters getInstance(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException
Generates a parameter object for the specified algorithm, as supplied by the specified provider, if such an algorithm is available from the provider.
The returned parameter object must be initialized via a call toinit, using an appropriate parameter specification or parameter encoding.
Parameters:
algorithm - the name of the algorithm requested.
provider - the name of the provider.
Returns:
the new parameter object.
Throws:
[NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security") - if the algorithm is not available in the package supplied by the requested provider.
[NoSuchProviderException](../../java/security/NoSuchProviderException.html "class in java.security") - if the provider is not available in the environment.
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if the provider name is null or empty.
See Also:
getInstance
public static AlgorithmParameters getInstance(String algorithm, Provider provider) throws NoSuchAlgorithmException
Generates a parameter object for the specified algorithm, as supplied by the specified provider, if such an algorithm is available from the provider. Note: the provider doesn't have to be registered.
The returned parameter object must be initialized via a call toinit, using an appropriate parameter specification or parameter encoding.
Parameters:
algorithm - the name of the algorithm requested.
provider - the name of the provider.
Returns:
the new parameter object.
Throws:
[NoSuchAlgorithmException](../../java/security/NoSuchAlgorithmException.html "class in java.security") - if the algorithm is not available in the package supplied by the requested provider.
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if the provider is null.
Since:
1.4
See Also:
getProvider
public final Provider getProvider()
Returns the provider of this parameter object.
Returns:
the provider of this parameter object
init
public final void init(AlgorithmParameterSpec paramSpec) throws InvalidParameterSpecException
Initializes this parameter object using the parameters specified in paramSpec.
Parameters:
paramSpec - the parameter specification.
Throws:
[InvalidParameterSpecException](../../java/security/spec/InvalidParameterSpecException.html "class in java.security.spec") - if the given parameter specification is inappropriate for the initialization of this parameter object, or if this parameter object has already been initialized.
init
public final void init(byte[] params) throws IOException
Imports the specified parameters and decodes them according to the primary decoding format for parameters. The primary decoding format for parameters is ASN.1, if an ASN.1 specification for this type of parameters exists.
Parameters:
params - the encoded parameters.
Throws:
[IOException](../../java/io/IOException.html "class in java.io") - on decoding errors, or if this parameter object has already been initialized.
init
public final void init(byte[] params, String format) throws IOException
Imports the parameters from params and decodes them according to the specified decoding scheme. If format is null, the primary decoding format for parameters is used. The primary decoding format is ASN.1, if an ASN.1 specification for these parameters exists.
Parameters:
params - the encoded parameters.
format - the name of the decoding scheme.
Throws:
[IOException](../../java/io/IOException.html "class in java.io") - on decoding errors, or if this parameter object has already been initialized.
getParameterSpec
public final <T extends AlgorithmParameterSpec> T getParameterSpec(Class paramSpec) throws InvalidParameterSpecException
Returns a (transparent) specification of this parameter object.paramSpec identifies the specification class in which the parameters should be returned. It could, for example, beDSAParameterSpec.class, to indicate that the parameters should be returned in an instance of the DSAParameterSpec class.
Parameters:
paramSpec - the specification class in which the parameters should be returned.
Returns:
the parameter specification.
Throws:
[InvalidParameterSpecException](../../java/security/spec/InvalidParameterSpecException.html "class in java.security.spec") - if the requested parameter specification is inappropriate for this parameter object, or if this parameter object has not been initialized.
getEncoded
public final byte[] getEncoded() throws IOException
Returns the parameters in their primary encoding format. The primary encoding format for parameters is ASN.1, if an ASN.1 specification for this type of parameters exists.
Returns:
the parameters encoded using their primary encoding format.
Throws:
[IOException](../../java/io/IOException.html "class in java.io") - on encoding errors, or if this parameter object has not been initialized.
getEncoded
public final byte[] getEncoded(String format) throws IOException
Returns the parameters encoded in the specified scheme. If format is null, the primary encoding format for parameters is used. The primary encoding format is ASN.1, if an ASN.1 specification for these parameters exists.
Parameters:
format - the name of the encoding format.
Returns:
the parameters encoded using the specified encoding scheme.
Throws:
[IOException](../../java/io/IOException.html "class in java.io") - on encoding errors, or if this parameter object has not been initialized.
toString
public final String toString()
Returns a formatted string describing the parameters.
Overrides:
[toString](../../java/lang/Object.html#toString%28%29) in class [Object](../../java/lang/Object.html "class in java.lang")
Returns:
a formatted string describing the parameters, or null if this parameter object has not been initialized.
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