AlgorithmParameters (Java Platform SE 7 )

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).
Once an AlgorithmParameters object is obtained, it must be initialized via a call to init, using an appropriate parameter specification or parameter encoding.
A transparent parameter specification is obtained from an AlgorithmParameters object via a call to getParameterSpec, and a byte encoding of the parameters is obtained via a call to getEncoded.
Every implementation of the Java platform is required to support the following standard AlgorithmParameters algorithms:
- AES
- DES
- DESede
- DiffieHellman
- DSA
These algorithms are described in the AlgorithmParameters section of the Java Cryptography Architecture Standard Algorithm Name Documentation. Consult the release documentation for your implementation to see if any other algorithms are supported.
Since:

1.2

See Also:
AlgorithmParameterSpec, DSAParameterSpec, KeyPairGenerator

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`AlgorithmParameters(AlgorithmParametersSpi paramSpi, Provider provider, String algorithm)` Creates an AlgorithmParameters object.

Method Summary

Methods
Modifier and Type	Method and Description
`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)` Returns a parameter object for the specified algorithm.
`static AlgorithmParameters`	`getInstance(String algorithm, Provider provider)` Returns a parameter object for the specified algorithm.
`static AlgorithmParameters`	`getInstance(String algorithm, String provider)` Returns a parameter object for the specified algorithm.
`<T extends AlgorithmParameterSpec> T`	`getParameterSpec(Class<T> 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(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

- 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
```
    Returns a parameter object for the specified algorithm.
    This method traverses the list of registered security Providers, starting with the most preferred Provider. A new AlgorithmParameters object encapsulating the AlgorithmParametersSpi implementation from the first Provider that supports the specified algorithm is returned.
    Note that the list of registered providers may be retrieved via the Security.getProviders() method.
    The returned parameter object must be initialized via a call to init, using an appropriate parameter specification or parameter encoding.
    
    Parameters:
    algorithm - the name of the algorithm requested. See the AlgorithmParameters section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard algorithm names.
    
    Returns:
    the new parameter object.
    
    Throws:
    
    NoSuchAlgorithmException - if no Provider supports an AlgorithmParametersSpi implementation for the specified algorithm.
    See Also:
    Provider
  - getInstance
```
public static AlgorithmParameters getInstance(String algorithm,
                              String provider)
                                       throws NoSuchAlgorithmException,
                                              NoSuchProviderException
```
    Returns a parameter object for the specified algorithm.
    A new AlgorithmParameters object encapsulating the AlgorithmParametersSpi implementation from the specified provider is returned. The specified provider must be registered in the security provider list.
    Note that the list of registered providers may be retrieved via the Security.getProviders() method.
    The returned parameter object must be initialized via a call to init, using an appropriate parameter specification or parameter encoding.
    
    Parameters:
    algorithm - the name of the algorithm requested. See the AlgorithmParameters section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard algorithm names.
    provider - the name of the provider.
    
    Returns:
    the new parameter object.
    
    Throws:
    
    NoSuchAlgorithmException - if an AlgorithmParametersSpi implementation for the specified algorithm is not available from the specified provider.
    
    NoSuchProviderException - if the specified provider is not registered in the security provider list.
    
    IllegalArgumentException - if the provider name is null or empty.
    See Also:
    Provider
  - getInstance
```
public static AlgorithmParameters getInstance(String algorithm,
                              Provider provider)
                                       throws NoSuchAlgorithmException
```
    Returns a parameter object for the specified algorithm.
    A new AlgorithmParameters object encapsulating the AlgorithmParametersSpi implementation from the specified Provider object is returned. Note that the specified Provider object does not have to be registered in the provider list.
    The returned parameter object must be initialized via a call to init, using an appropriate parameter specification or parameter encoding.
    
    Parameters:
    algorithm - the name of the algorithm requested. See the AlgorithmParameters section in the Java Cryptography Architecture Standard Algorithm Name Documentation for information about standard algorithm names.
    provider - the name of the provider.
    
    Returns:
    the new parameter object.
    
    Throws:
    
    NoSuchAlgorithmException - if an AlgorithmParameterGeneratorSpi implementation for the specified algorithm is not available from the specified Provider object.
    
    IllegalArgumentException - if the provider is null.
    Since:
    
    1.4
    
    See Also:
    Provider
  - 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 - 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 - 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 - on decoding errors, or if this parameter object has already been initialized.
  - getParameterSpec
```
public final <T extends AlgorithmParameterSpec> T getParameterSpec(Class<T> 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, be DSAParameterSpec.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 - 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 - 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 - 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 in class Object
    
    Returns:
    a formatted string describing the parameters, or null if this parameter object has not been initialized.

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Class AlgorithmParameters

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

AlgorithmParameters

Method Detail

getAlgorithm

getInstance

getInstance

getInstance

getProvider

init

init

init

getParameterSpec

getEncoded

getEncoded

toString