Class KeySelector

A selector that finds and returns a key using the data contained in a KeyInfo object. An example of an implementation of this class is one that searches a KeyStore for trusted keys that match information contained in a KeyInfo.

Whether or not the returned key is trusted and the mechanisms used to determine that is implementation-specific.

Constructors

KeySelector

protected KeySelector()

Default no-args constructor; intended for invocation by subclasses only.

Methods

select

public abstract KeySelectorResult select(KeyInfo keyInfo,
                                         KeySelector.Purpose purpose,
                                         AlgorithmMethod method,
                                         XMLCryptoContext context)
                                  throws KeySelectorException

Attempts to find a key that satisfies the specified constraints.

Parameters:

keyInfo - a KeyInfo (may be null)

purpose - the key's purpose (KeySelector.Purpose.SIGN, KeySelector.Purpose.VERIFY, KeySelector.Purpose.ENCRYPT, or KeySelector.Purpose.DECRYPT)

method - the algorithm method that this key is to be used for. Only keys that are compatible with the algorithm and meet the constraints of the specified algorithm should be returned.

context - an XMLCryptoContext that may contain useful information for finding an appropriate key. If this key selector supports resolving RetrievalMethod types, the context's baseURI and dereferencer parameters (if specified) should be used by the selector to resolve and dereference the URI.

Returns:

the result of the key selector

Throws:

KeySelectorException - if an exceptional condition occurs while attempting to find a key. Note that an inability to find a key is not considered an exception (null should be returned in that case). However, an error condition (ex: network communications failure) that prevented the KeySelector from finding a potential key should be considered an exception.

ClassCastException - if the data type of method is not supported by this key selector

singletonKeySelector

public static KeySelector singletonKeySelector(Key key)

Returns a KeySelector that always selects the specified key, regardless of the KeyInfo passed to it.

Parameters:

key - the sole key to be stored in the key selector

Returns:

a key selector that always selects the specified key

Throws:

NullPointerException - if key is null