# Class KeyInfoFactory

java.lang.Object
javax.xml.crypto.dsig.keyinfo.KeyInfoFactory

public abstract class KeyInfoFactory extends Object
A factory for creating `KeyInfo` objects from scratch or for unmarshalling a `KeyInfo` object from a corresponding XML representation.

Each instance of `KeyInfoFactory` supports a specific XML mechanism type. To create a `KeyInfoFactory`, call one of the static `getInstance` methods, passing in the XML mechanism type desired, for example:

> `KeyInfoFactory factory = KeyInfoFactory.getInstance("DOM");`

The objects that this factory produces will be based on DOM and abide by the DOM interoperability requirements as defined in the DOM Mechanism Requirements. See the `KeyInfoFactory` section in the Java Security Standard Algorithm Names Specification for a list of standard mechanism types.

`KeyInfoFactory` implementations are registered and loaded using the `Provider` mechanism. For example, a service provider that supports the DOM mechanism would be specified in the `Provider` subclass as:

        put("KeyInfoFactory.DOM", "org.example.DOMKeyInfoFactory");

Also, the `XMLStructure`s that are created by this factory may contain state specific to the `KeyInfo` and are not intended to be reusable.

An implementation MUST minimally support the default mechanism type: DOM.

Note that a caller must use the same `KeyInfoFactory` instance to create the `XMLStructure`s of a particular `KeyInfo` object. The behavior is undefined if `XMLStructure`s from different providers or different mechanism types are used together.

Concurrent Access

The static methods of this class are guaranteed to be thread-safe. Multiple threads may concurrently invoke the static methods defined in this class with no ill effects.

However, this is not true for the non-static methods defined by this class. Unless otherwise documented by a specific provider, threads that need to access a single `KeyInfoFactory` instance concurrently should synchronize amongst themselves and provide the necessary locking. Multiple threads each manipulating a different `KeyInfoFactory` instance need not synchronize.

Since:
  1.6
External Specifications
  - Java Security Standard Algorithm Names

## Constructor Summary

Constructors
Modifier
Constructor
Description
`protected`
`KeyInfoFactory()`
Default constructor, for invocation by subclasses.

## Method Summary

Modifier and Type
Method
Description
`static KeyInfoFactory`
`getInstance()`
Returns a `KeyInfoFactory` that supports the default XML processing mechanism and representation type ("DOM").
`static KeyInfoFactory`
`getInstance(String mechanismType)`
Returns a `KeyInfoFactory` that supports the specified XML processing mechanism and representation type (ex: "DOM").
`static KeyInfoFactory`
`getInstance(String mechanismType, String provider)`
Returns a `KeyInfoFactory` that supports the requested XML processing mechanism and representation type (ex: "DOM"), as supplied by the specified provider.
`static KeyInfoFactory`
`getInstance(String mechanismType, Provider provider)`
Returns a `KeyInfoFactory` that supports the requested XML processing mechanism and representation type (ex: "DOM"), as supplied by the specified provider.
`final String`
`getMechanismType()`
Returns the type of the XML processing mechanism and representation supported by this `KeyInfoFactory` (ex: "DOM")
`final Provider`
`getProvider()`
Returns the provider of this `KeyInfoFactory`.
`abstract URIDereferencer`
`getURIDereferencer()`
Returns a reference to the `URIDereferencer` that is used by default to dereference URIs in `RetrievalMethod` objects.
`abstract boolean`
`isFeatureSupported(String feature)`
Indicates whether a specified feature is supported.
`abstract KeyInfo`
`newKeyInfo(List<? extends XMLStructure> content)`
Creates a `KeyInfo` containing the specified list of key information types.
`abstract KeyInfo`
`newKeyInfo(List<? extends XMLStructure> content, String id)`
Creates a `KeyInfo` containing the specified list of key information types and optional id.
`abstract KeyName`
`newKeyName(String name)`
Creates a `KeyName` from the specified name.
`abstract KeyValue`
`newKeyValue(PublicKey key)`
Creates a `KeyValue` from the specified public key.
`abstract PGPData`
`newPGPData(byte[] keyId)`
Creates a `PGPData` from the specified PGP public key identifier.
`abstract PGPData`
`newPGPData(byte[] keyId, byte[] keyPacket, List<? extends XMLStructure> other)`
Creates a `PGPData` from the specified PGP public key identifier, and optional key material packet and list of external elements.
`abstract PGPData`
`newPGPData(byte[] keyPacket, List<? extends XMLStructure> other)`
Creates a `PGPData` from the specified PGP key material packet and optional list of external elements.
`abstract RetrievalMethod`
`newRetrievalMethod(String uri)`
Creates a `RetrievalMethod` from the specified URI.
`abstract RetrievalMethod`
`newRetrievalMethod(String uri, String type, List<? extends Transform> transforms)`
Creates a `RetrievalMethod` from the specified parameters.
`abstract X509Data`
`newX509Data(List<?> content)`
Creates a `X509Data` containing the specified list of X.509 content.
`abstract X509IssuerSerial`
`newX509IssuerSerial(String issuerName, BigInteger serialNumber)`
Creates an `X509IssuerSerial` from the specified X.500 issuer distinguished name and serial number.
`abstract KeyInfo`
`unmarshalKeyInfo(XMLStructure xmlStructure)`
Unmarshals a new `KeyInfo` instance from a mechanism-specific `XMLStructure` (ex: `DOMStructure`) instance.

### Methods declared in class Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

## Constructor Details

### KeyInfoFactory

protected KeyInfoFactory()
Default constructor, for invocation by subclasses.

## Method Details

### getInstance

public static KeyInfoFactory getInstance(String mechanismType)
Returns a `KeyInfoFactory` that supports the specified XML processing mechanism and representation type (ex: "DOM").

This method uses the standard JCA provider lookup mechanism to locate and instantiate a `KeyInfoFactory` implementation of the desired mechanism type. It traverses the list of registered security `Provider`s, starting with the most preferred `Provider`. A new `KeyInfoFactory` object from the first `Provider` that supports the specified mechanism is returned.

Note that the list of registered providers may be retrieved via the `Security.getProviders()` method.

Implementation Note:
  The JDK Reference Implementation additionally uses the `jdk.security.provider.preferred` `Security` property to determine the preferred provider order for the specified algorithm. This may be different than the order of providers returned by `Security.getProviders()`.
Parameters:
  `mechanismType` - the type of the XML processing mechanism and representation. See the `KeyInfoFactory` section in the Java Security Standard Algorithm Names Specification for a list of standard mechanism types.
Returns:
  a new `KeyInfoFactory`
Throws:
  `NullPointerException` - if `mechanismType` is `null`
  `NoSuchMechanismException` - if no `Provider` supports a `KeyInfoFactory` implementation for the specified mechanism
External Specifications
  - Java Security Standard Algorithm Names
See Also:
  - `Provider`

### getInstance

public static KeyInfoFactory getInstance(String mechanismType, Provider provider)
Returns a `KeyInfoFactory` that supports the requested XML processing mechanism and representation type (ex: "DOM"), as supplied by the specified provider. Note that the specified `Provider` object does not have to be registered in the provider list.

Parameters:
  `mechanismType` - the type of the XML processing mechanism and representation. See the `KeyInfoFactory` section in the Java Security Standard Algorithm Names Specification for a list of standard mechanism types.
  `provider` - the `Provider` object
Returns:
  a new `KeyInfoFactory`
Throws:
  `NullPointerException` - if `mechanismType` or `provider` are `null`
  `NoSuchMechanismException` - if a `KeyInfoFactory` implementation for the specified mechanism is not available from the specified `Provider` object
External Specifications
  - Java Security Standard Algorithm Names
See Also:
  - `Provider`

### getInstance

public static KeyInfoFactory getInstance(String mechanismType, String provider) throws NoSuchProviderException
Returns a `KeyInfoFactory` that supports the requested XML processing mechanism and representation type (ex: "DOM"), as supplied by the specified provider. 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.

Parameters:
  `mechanismType` - the type of the XML processing mechanism and representation. See the `KeyInfoFactory` section in the Java Security Standard Algorithm Names Specification for a list of standard mechanism types.
  `provider` - the string name of the provider
Returns:
  a new `KeyInfoFactory`
Throws:
  `NoSuchProviderException` - if the specified provider is not registered in the security provider list
  `NullPointerException` - if `mechanismType` or `provider` are `null`
  `NoSuchMechanismException` - if a `KeyInfoFactory` implementation for the specified mechanism is not available from the specified provider
External Specifications
  - Java Security Standard Algorithm Names
See Also:
  - `Provider`

### getInstance

public static KeyInfoFactory getInstance()
Returns a `KeyInfoFactory` that supports the default XML processing mechanism and representation type ("DOM").

This method uses the standard JCA provider lookup mechanism to locate and instantiate a `KeyInfoFactory` implementation of the default mechanism type. It traverses the list of registered security `Provider`s, starting with the most preferred `Provider`. A new `KeyInfoFactory` object from the first `Provider` that supports the DOM mechanism is returned.

Note that the list of registered providers may be retrieved via the `Security.getProviders()` method.

Implementation Note:
  The JDK Reference Implementation additionally uses the `jdk.security.provider.preferred` `Security` property to determine the preferred provider order for the specified algorithm. This may be different than the order of providers returned by `Security.getProviders()`.
Returns:
  a new `KeyInfoFactory`
Throws:
  `NoSuchMechanismException` - if no `Provider` supports a `KeyInfoFactory` implementation for the DOM mechanism
See Also:
  - `Provider`

### getMechanismType

public final String getMechanismType()
Returns the type of the XML processing mechanism and representation supported by this `KeyInfoFactory` (ex: "DOM")

Returns:
  the XML processing mechanism type supported by this `KeyInfoFactory`

### getProvider

public final Provider getProvider()
Returns the provider of this `KeyInfoFactory`.

Returns:
  the provider of this `KeyInfoFactory`

### newKeyInfo

public abstract KeyInfo newKeyInfo(List<? extends XMLStructure> content)
Creates a `KeyInfo` containing the specified list of key information types.

Parameters:
  `content` - a list of one or more `XMLStructure`s representing key information types. The list is defensively copied to protect against subsequent modification.
Returns:
  a `KeyInfo`
Throws:
  `NullPointerException` - if `content` is `null`
  `IllegalArgumentException` - if `content` is empty
  `ClassCastException` - if `content` contains any entries that are not of type `XMLStructure`

### newKeyInfo

public abstract KeyInfo newKeyInfo(List<? extends XMLStructure> content, String id)
Creates a `KeyInfo` containing the specified list of key information types and optional id. The `id` parameter represents the value of an XML `ID` attribute and is useful for referencing the `KeyInfo` from other XML structures.

Parameters:
  `content` - a list of one or more `XMLStructure`s representing key information types. The list is defensively copied to protect against subsequent modification.
  `id` - the value of an XML `ID` (may be `null`)
Returns:
  a `KeyInfo`
Throws:
  `NullPointerException` - if `content` is `null`
  `IllegalArgumentException` - if `content` is empty
  `ClassCastException` - if `content` contains any entries that are not of type `XMLStructure`

### newKeyName

public abstract KeyName newKeyName(String name)
Creates a `KeyName` from the specified name.

Parameters:
  `name` - the name that identifies the key
Returns:
  a `KeyName`
Throws:
  `NullPointerException` - if `name` is `null`

### newKeyValue

public abstract KeyValue newKeyValue(PublicKey key) throws KeyException
Creates a `KeyValue` from the specified public key.

Parameters:
  `key` - the public key
Returns:
  a `KeyValue`
Throws:
  `KeyException` - if the `key`'s algorithm is not recognized or supported by this `KeyInfoFactory`
  `NullPointerException` - if `key` is `null`

### newPGPData

public abstract PGPData newPGPData(byte[] keyId)
Creates a `PGPData` from the specified PGP public key identifier.

Parameters:
  `keyId` - a PGP public key identifier as defined in RFC 2440, section 11.2. The array is cloned to protect against subsequent modification.
Returns:
  a `PGPData`
Throws:
  `NullPointerException` - if `keyId` is `null`
  `IllegalArgumentException` - if the key id is not in the correct format

### newPGPData

public abstract PGPData newPGPData(byte[] keyId, byte[] keyPacket, List<? extends XMLStructure> other)
Creates a `PGPData` from the specified PGP public key identifier, and optional key material packet and list of external elements.

Parameters:
  `keyId` - a PGP public key identifier as defined in RFC 2440, section 11.2. The array is cloned to protect against subsequent modification.
  `keyPacket` - a PGP key material packet as defined in RFC 2440, section 5.5. The array is cloned to protect against subsequent modification. May be `null`.
  `other` - a list of `XMLStructure`s representing elements from an external namespace. The list is defensively copied to protect against subsequent modification. May be `null` or empty.
Returns:
  a `PGPData`
Throws:
  `NullPointerException` - if `keyId` is `null`
  `IllegalArgumentException` - if the `keyId` or `keyPacket` is not in the correct format. For `keyPacket`, the format of the packet header is checked and the tag is verified that it is of type key material. The contents and format of the packet body are not checked.
  `ClassCastException` - if `other` contains any entries that are not of type `XMLStructure`

### newPGPData

public abstract PGPData newPGPData(byte[] keyPacket, List<? extends XMLStructure> other)
Creates a `PGPData` from the specified PGP key material packet and optional list of external elements.

Parameters:
  `keyPacket` - a PGP key material packet as defined in RFC 2440, section 5.5. The array is cloned to protect against subsequent modification.
  `other` - a list of `XMLStructure`s representing elements from an external namespace. The list is defensively copied to protect against subsequent modification. May be `null` or empty.
Returns:
  a `PGPData`
Throws:
  `NullPointerException` - if `keyPacket` is `null`
  `IllegalArgumentException` - if `keyPacket` is not in the correct format. For `keyPacket`, the format of the packet header is checked and the tag is verified that it is of type key material. The contents and format of the packet body are not checked.
  `ClassCastException` - if `other` contains any entries that are not of type `XMLStructure`

### newRetrievalMethod

public abstract RetrievalMethod newRetrievalMethod(String uri)
Creates a `RetrievalMethod` from the specified URI.

Parameters:
  `uri` - the URI that identifies the `KeyInfo` information to be retrieved
Returns:
  a `RetrievalMethod`
Throws:
  `NullPointerException` - if `uri` is `null`
  `IllegalArgumentException` - if `uri` is not RFC 2396 compliant

### newRetrievalMethod

public abstract RetrievalMethod newRetrievalMethod(String uri, String type, List<? extends Transform> transforms)
Creates a `RetrievalMethod` from the specified parameters.

Parameters:
  `uri` - the URI that identifies the `KeyInfo` information to be retrieved
  `type` - a URI that identifies the type of `KeyInfo` information to be retrieved (may be `null`)
  `transforms` - a list of `Transform`s. The list is defensively copied to protect against subsequent modification. May be `null` or empty.
Returns:
  a `RetrievalMethod`
Throws:
  `NullPointerException` - if `uri` is `null`
  `IllegalArgumentException` - if `uri` is not RFC 2396 compliant
  `ClassCastException` - if `transforms` contains any entries that are not of type `Transform`

### newX509Data

public abstract X509Data newX509Data(List<?> content)
Creates a `X509Data` containing the specified list of X.509 content.

Parameters:
  `content` - a list of one or more X.509 content types. Valid types are `String` (subject names), `byte[]` (subject key ids), `X509Certificate`, `X509CRL`, or `XMLStructure` (`X509IssuerSerial` objects or elements from an external namespace). Subject names are distinguished names in RFC 2253 String format. Implementations MUST support the attribute type keywords defined in RFC 2253 (CN, L, ST, O, OU, C, STREET, DC and UID). Implementations MAY support additional keywords. The list is defensively copied to protect against subsequent modification.
Returns:
  a `X509Data`
Throws:
  `NullPointerException` - if `content` is `null`
  `IllegalArgumentException` - if `content` is empty, or if a subject name is not RFC 2253 compliant or one of the attribute type keywords is not recognized.
  `ClassCastException` - if `content` contains any entries that are not of one of the valid types mentioned above

### newX509IssuerSerial

public abstract X509IssuerSerial newX509IssuerSerial(String issuerName, BigInteger serialNumber)
Creates an `X509IssuerSerial` from the specified X.500 issuer distinguished name and serial number.

Parameters:
  `issuerName` - the issuer's distinguished name in RFC 2253 String format. Implementations MUST support the attribute type keywords defined in RFC 2253 (CN, L, ST, O, OU, C, STREET, DC and UID). Implementations MAY support additional keywords.
  `serialNumber` - the serial number
Returns:
  an `X509IssuerSerial`
Throws:
  `NullPointerException` - if `issuerName` or `serialNumber` are `null`
  `IllegalArgumentException` - if the issuer name is not RFC 2253 compliant or one of the attribute type keywords is not recognized.

### isFeatureSupported

public abstract boolean isFeatureSupported(String feature)
Indicates whether a specified feature is supported.

Parameters:
  `feature` - the feature name (as an absolute URI)
Returns:
  `true` if the specified feature is supported, `false` otherwise
Throws:
  `NullPointerException` - if `feature` is `null`

### getURIDereferencer

public abstract URIDereferencer getURIDereferencer()
Returns a reference to the `URIDereferencer` that is used by default to dereference URIs in `RetrievalMethod` objects.

Returns:
  a reference to the default `URIDereferencer`

### unmarshalKeyInfo

public abstract KeyInfo unmarshalKeyInfo(XMLStructure xmlStructure) throws MarshalException
Unmarshals a new `KeyInfo` instance from a mechanism-specific `XMLStructure` (ex: `DOMStructure`) instance.

Parameters:
  `xmlStructure` - a mechanism-specific XML structure from which to unmarshal the keyinfo from
Returns:
  the `KeyInfo`
Throws:
  `NullPointerException` - if `xmlStructure` is `null`
  `ClassCastException` - if the type of `xmlStructure` is inappropriate for this factory
  `MarshalException` - if an unrecoverable exception occurs during unmarshalling