https://openjdk.java.net/ 
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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package org.ietf.jgss;

import java.security.Provider;


This class serves as a factory for other important GSS-API classes and also provides information about the mechanisms that are supported. It can create instances of classes implementing the following three GSS-API interfaces: GSSName, GSSCredential, and GSSContext. It also has methods to query for the list of available mechanisms and the nametypes that each mechanism supports.

An instance of the default GSSManager subclass may be obtained through the static method 
getInstance, but applications are free to instantiate other subclasses of GSSManager. The default GSSManager instance
will support the Kerberos v5 GSS-API mechanism in addition to any
others. This mechanism is identified by the Oid "1.2.840.113554.1.2.2"
and is defined in RFC 1964.

A subclass extending the GSSManager abstract class may be
implemented  as a modular provider based layer that utilizes some well
known  service provider specification. The GSSManager API
allows the application to set provider preferences on
such an implementation. These methods also allow the implementation to
throw a well-defined exception in case provider based configuration is
not supported. Applications that expect to be portable should be aware
of this and recover cleanly by catching the exception.

It is envisioned that there will be three most common ways in which
providers will be used:


    

  1.  The application does not care about what provider is used (the
default case).

  2.  The application wants a particular provider to be used
preferentially, either for a particular mechanism or all the
time, irrespective of mechanism.

  3.  The application wants to use the locally configured providers
as far as possible but if support is missing for one or more
mechanisms then it wants to fall back on its own provider.


The GSSManager class has two methods that enable these modes of usage: addProviderAtFront and addProviderAtEnd. These methods have the effect of creating an ordered list of <provider,
oid> pairs  where each pair indicates a preference of provider
for a given oid.

It is important to note that there are certain interactions
between the different GSS-API objects that are created by a
GSSManager, where the provider that is used for a particular mechanism
might need to be consistent across all objects. For instance, if a
GSSCredential contains elements from a provider p for a mechanism
m, it should generally be passed in to a GSSContext that will use
provider p for the mechanism m. A simple rule of thumb
that will maximize portability is that objects created from different
GSSManager's should not be mixed, and if possible, a different
GSSManager instance should be created if the application wants to invoke
the addProviderAtFront method on a GSSManager that has
already created an object.

 Here is some sample code showing how the GSSManager might be used: 


    GSSManager manager = GSSManager.getInstance();
    Oid krb5Mechanism = new Oid("1.2.840.113554.1.2.2");
    Oid krb5PrincipalNameType = new Oid("1.2.840.113554.1.2.2.1");
    // Identify who the client wishes to be
    GSSName userName = manager.createName("duke", GSSName.NT_USER_NAME);
    // Identify the name of the server. This uses a Kerberos specific
    // name format.
    GSSName serverName = manager.createName("nfs/foo.sun.com",
                                            krb5PrincipalNameType);
    // Acquire credentials for the user
    GSSCredential userCreds = manager.createCredential(userName,
                                            GSSCredential.DEFAULT_LIFETIME,
                                            krb5Mechanism,
                                            GSSCredential.INITIATE_ONLY);
    // Instantiate and initialize a security context that will be
    // established with the server
    GSSContext context = manager.createContext(serverName,
                                               krb5Mechanism,
                                               userCreds,
                                               GSSContext.DEFAULT_LIFETIME);


The server side might use the following variation of this source:


    // Acquire credentials for the server
    GSSCredential serverCreds = manager.createCredential(serverName,
                                            GSSCredential.DEFAULT_LIFETIME,
                                            krb5Mechanism,
                                            GSSCredential.ACCEPT_ONLY);
    // Instantiate and initialize a security context that will
    // wait for an establishment request token from the client
    GSSContext context = manager.createContext(serverCreds);



Author:Mayank Upadhyay
See Also:
Since:1.4
/**
 * This class serves as a factory for other important
 * GSS-API classes and also provides information about the mechanisms that
 * are supported. It can create instances of classes
 * implementing the following three GSS-API interfaces: {@link
 * GSSName GSSName}, {@link GSSCredential GSSCredential}, and {@link
 * GSSContext GSSContext}. It also has methods to query for the list
 * of available mechanisms and the nametypes that each mechanism
 * supports.<p>
 *
 * An instance of the default <code>GSSManager</code> subclass
 * may be obtained through the static method {@link #getInstance()
 * getInstance}, but applications are free to instantiate other subclasses
 * of <code>GSSManager</code>. The default <code>GSSManager</code> instance
 * will support the Kerberos v5 GSS-API mechanism in addition to any
 * others. This mechanism is identified by the Oid "1.2.840.113554.1.2.2"
 * and is defined in RFC 1964.<p>
 *
 * A subclass extending the <code>GSSManager</code> abstract class may be
 * implemented  as a modular provider based layer that utilizes some well
 * known  service provider specification. The <code>GSSManager</code> API
 * allows the application to set provider preferences on
 * such an implementation. These methods also allow the implementation to
 * throw a well-defined exception in case provider based configuration is
 * not supported. Applications that expect to be portable should be aware
 * of this and recover cleanly by catching the exception.<p>
 *
 * It is envisioned that there will be three most common ways in which
 * providers will be used:<p>
 * <ol>
 * <li> The application does not care about what provider is used (the
 * default case).
 * <li> The application wants a particular provider to be used
 * preferentially, either for a particular mechanism or all the
 * time, irrespective of mechanism.
 * <li> The application wants to use the locally configured providers
 * as far as possible but if support is missing for one or more
 * mechanisms then it wants to fall back on its own provider.
 *</ol><p>
 *
 * The <code>GSSManager</code> class has two methods that enable these modes of
 * usage:  {@link #addProviderAtFront(Provider, Oid) addProviderAtFront} and
 * {@link #addProviderAtEnd(Provider, Oid) addProviderAtEnd}. These methods
 * have the effect of creating an ordered list of <i>&lt;provider,
 * oid&gt;</i> pairs  where each pair indicates a preference of provider
 * for a given oid.<p>
 *
 * It is important to note that there are certain interactions
 * between the different GSS-API objects that are created by a
 * GSSManager, where the provider that is used for a particular mechanism
 * might need to be consistent across all objects. For instance, if a
 * GSSCredential contains elements from a provider <i>p</i> for a mechanism
 * <i>m</i>, it should generally be passed in to a GSSContext that will use
 * provider <i>p</i> for the mechanism <i>m</i>. A simple rule of thumb
 * that will maximize portability is that objects created from different
 * GSSManager's should not be mixed, and if possible, a different
 * GSSManager instance should be created if the application wants to invoke
 * the <code>addProviderAtFront</code> method on a GSSManager that has
 * already created an object.<p>
 *
 *  Here is some sample code showing how the GSSManager might be used: <p>
 * <pre>
 *     GSSManager manager = GSSManager.getInstance();
 *
 *     Oid krb5Mechanism = new Oid("1.2.840.113554.1.2.2");
 *     Oid krb5PrincipalNameType = new Oid("1.2.840.113554.1.2.2.1");
 *
 *     // Identify who the client wishes to be
 *     GSSName userName = manager.createName("duke", GSSName.NT_USER_NAME);
 *
 *     // Identify the name of the server. This uses a Kerberos specific
 *     // name format.
 *     GSSName serverName = manager.createName("nfs/foo.sun.com",
 *                                             krb5PrincipalNameType);
 *
 *     // Acquire credentials for the user
 *     GSSCredential userCreds = manager.createCredential(userName,
 *                                             GSSCredential.DEFAULT_LIFETIME,
 *                                             krb5Mechanism,
 *                                             GSSCredential.INITIATE_ONLY);
 *
 *     // Instantiate and initialize a security context that will be
 *     // established with the server
 *     GSSContext context = manager.createContext(serverName,
 *                                                krb5Mechanism,
 *                                                userCreds,
 *                                                GSSContext.DEFAULT_LIFETIME);
 * </pre><p>
 *
 * The server side might use the following variation of this source:<p>
 *
 * <pre>
 *     // Acquire credentials for the server
 *     GSSCredential serverCreds = manager.createCredential(serverName,
 *                                             GSSCredential.DEFAULT_LIFETIME,
 *                                             krb5Mechanism,
 *                                             GSSCredential.ACCEPT_ONLY);
 *
 *     // Instantiate and initialize a security context that will
 *     // wait for an establishment request token from the client
 *     GSSContext context = manager.createContext(serverCreds);
 * </pre>
 *
 * @author Mayank Upadhyay
 * @see GSSName
 * @see GSSCredential
 * @see GSSContext
 * @since 1.4
 */
public abstract class GSSManager {

    
Returns the default GSSManager implementation.

Returns:a GSSManager implementation
/**
     * Returns the default GSSManager implementation.
     *
     * @return a GSSManager implementation
     */
    public static GSSManager getInstance() {
        return new sun.security.jgss.GSSManagerImpl();
    }

    
Returns a list of mechanisms that are available to GSS-API callers through this GSSManager. The default GSSManager obtained from the getInstance() method includes the Oid "1.2.840.113554.1.2.2" in its list. This Oid identifies the Kerberos v5 GSS-API mechanism that is defined in RFC 1964. 
Returns:an array of Oid objects corresponding to the mechanisms that
are available. A null value is returned when no
mechanism are available (an example of this would be when mechanism
are dynamically configured, and currently no mechanisms are
installed).
/**
     * Returns a list of mechanisms that are available to GSS-API callers
     * through this GSSManager. The default GSSManager obtained from the
     * {@link #getInstance() getInstance()} method includes the Oid
     * "1.2.840.113554.1.2.2" in its list. This Oid identifies the Kerberos
     * v5 GSS-API mechanism that is defined in RFC 1964.
     *
     * @return an array of Oid objects corresponding to the mechanisms that
     * are available. A <code>null</code> value is returned when no
     * mechanism are available (an example of this would be when mechanism
     * are dynamically configured, and currently no mechanisms are
     * installed).
     */
    public  abstract Oid[] getMechs();

    
Returns then name types supported by the indicated mechanism.
 The default GSSManager instance includes support for the Kerberos v5 mechanism. When this mechanism ("1.2.840.113554.1.2.2") is indicated, the returned list will contain at least the following nametypes: GSSName.NT_HOSTBASED_SERVICE, GSSName.NT_EXPORT_NAME, and the Kerberos v5 specific Oid "1.2.840.113554.1.2.2.1". The namespace for the Oid "1.2.840.113554.1.2.2.1" is defined in RFC 1964. 
Params:
  • mech – the Oid of the mechanism to query
Throws:
See Also:
Returns:an array of Oid objects corresponding to the name types that
the mechanism supports.
/**
     * Returns then name types supported by the indicated mechanism.<p>
     *
     * The default GSSManager instance includes support for the Kerberos v5
     * mechanism. When this mechanism ("1.2.840.113554.1.2.2") is indicated,
     * the returned list will contain at least the following nametypes:
     * {@link GSSName#NT_HOSTBASED_SERVICE GSSName.NT_HOSTBASED_SERVICE},
     * {@link GSSName#NT_EXPORT_NAME GSSName.NT_EXPORT_NAME}, and the
     * Kerberos v5 specific Oid "1.2.840.113554.1.2.2.1". The namespace for
     * the Oid "1.2.840.113554.1.2.2.1" is defined in RFC 1964.
     *
     * @return an array of Oid objects corresponding to the name types that
     * the mechanism supports.
     * @param mech the Oid of the mechanism to query
     *
     * @see #getMechsForName(Oid)
     *
     * @throws GSSException containing the following
     * major error codes:
     *    {@link GSSException#BAD_MECH GSSException.BAD_MECH}
     *    {@link GSSException#FAILURE GSSException.FAILURE}
     */
    public abstract  Oid[] getNamesForMech(Oid mech)
        throws GSSException;

    
Returns a list of mechanisms that support the indicated name type.
 The Kerberos v5 mechanism ("1.2.840.113554.1.2.2") will always be returned in this list when the indicated nametype is one of GSSName.NT_HOSTBASED_SERVICE, GSSName.NT_EXPORT_NAME, or "1.2.840.113554.1.2.2.1". 
Params:
  • nameType – the Oid of the name type to look for
See Also:
Returns:an array of Oid objects corresponding to the mechanisms that
support the specified name type.  null is returned when no
mechanisms are found to support the specified name type.
/**
     * Returns a list of mechanisms that support the indicated name type.<p>
     *
     * The Kerberos v5 mechanism ("1.2.840.113554.1.2.2") will always be
     * returned in this list when the indicated nametype is one of
     * {@link GSSName#NT_HOSTBASED_SERVICE GSSName.NT_HOSTBASED_SERVICE},
     * {@link GSSName#NT_EXPORT_NAME GSSName.NT_EXPORT_NAME}, or
     * "1.2.840.113554.1.2.2.1".
     *
     * @return an array of Oid objects corresponding to the mechanisms that
     * support the specified name type.  <code>null</code> is returned when no
     * mechanisms are found to support the specified name type.
     * @param nameType the Oid of the name type to look for
     *
     * @see #getNamesForMech(Oid)
     */
    public abstract  Oid[] getMechsForName(Oid nameType);

    
Factory method to convert a string name from the
specified namespace to a GSSName object. In general, the
GSSName object created will contain multiple representations of the name, one for each mechanism that is supported; two examples that are exceptions to this are when the namespace type parameter indicates NT_EXPORT_NAME or when the GSS-API implementation is not multi-mechanism. It is not recommended to use this method with a NT_EXPORT_NAME type because representing a previously exported name consisting of arbitrary bytes as a String might cause problems with character encoding schemes. In such cases it is recommended that the bytes be passed in directly to the overloaded form of this method createName. 
Params:
  • nameStr – the string representing a printable form of the name to
create.
  • nameType – the Oid specifying the namespace of the printable name
supplied. null can be used to specify
that a mechanism specific default printable syntax should
be assumed by each mechanism that examines nameStr.
It is not advisable to use the nametype NT_EXPORT_NAME with this
method.
Throws:
See Also:
Returns:a GSSName representing the indicated principal
/**
     * Factory method to convert a string name from the
     * specified namespace to a GSSName object. In general, the
     * <code>GSSName</code> object created  will contain multiple
     * representations of the name, one for each mechanism that is
     * supported; two examples that are exceptions to this are when
     * the namespace type parameter indicates NT_EXPORT_NAME or when the
     * GSS-API implementation is not multi-mechanism. It is
     * not recommended to use this method with a NT_EXPORT_NAME type because
     * representing a previously exported name consisting of arbitrary bytes
     * as a String might cause problems with character encoding schemes. In
     * such cases it is recommended that the bytes be passed in directly to
     * the overloaded form of this method {@link #createName(byte[],
     * Oid) createName}.
     *
     * @param nameStr the string representing a printable form of the name to
     * create.
     * @param nameType the Oid specifying the namespace of the printable name
     * supplied. <code>null</code> can be used to specify
     * that a mechanism specific default printable syntax should
     * be assumed by each mechanism that examines nameStr.
     * It is not advisable to use the nametype NT_EXPORT_NAME with this
     * method.
     * @return a GSSName representing the indicated principal
     *
     * @see GSSName
     * @see GSSName#NT_EXPORT_NAME
     *
     * @throws GSSException containing the following
     * major error codes:
     *    {@link GSSException#BAD_NAMETYPE GSSException.BAD_NAMETYPE},
     *    {@link GSSException#BAD_NAME GSSException.BAD_NAME},
     *    {@link GSSException#BAD_MECH GSSException.BAD_MECH},
     *    {@link GSSException#FAILURE GSSException.FAILURE}
     */
    public abstract GSSName createName(String nameStr, Oid nameType)
        throws GSSException;

    
Factory method to convert a byte array containing a
name from the specified namespace to a GSSName object. In general,
the GSSName object created  will contain multiple
representations of the name, one for each mechanism that is
supported; two examples that are exceptions to this are when the
namespace type parameter indicates NT_EXPORT_NAME or when the
GSS-API implementation is not multi-mechanism. The bytes that are
passed in are interpreted by each underlying mechanism according to
some encoding scheme of its choice for the given nametype.

Params:
  • name – the byte array containing the name to create
  • nameType – the Oid specifying the namespace of the name supplied
in the byte array. null can be used to specify that a
mechanism specific default syntax should be assumed by each mechanism
that examines the byte array.
Throws:
See Also:
Returns:a GSSName representing the indicated principal
/**
     * Factory method to convert a byte array containing a
     * name from the specified namespace to a GSSName object. In general,
     * the <code>GSSName</code> object created  will contain multiple
     * representations of the name, one for each mechanism that is
     * supported; two examples that are exceptions to this are when the
     * namespace type parameter indicates NT_EXPORT_NAME or when the
     * GSS-API implementation is not multi-mechanism. The bytes that are
     * passed in are interpreted by each underlying mechanism according to
     * some encoding scheme of its choice for the given nametype.
     *
     * @param name the byte array containing the name to create
     * @param nameType the Oid specifying the namespace of the name supplied
     * in the byte array. <code>null</code> can be used to specify that a
     * mechanism specific default syntax should be assumed by each mechanism
     * that examines the byte array.
     * @return a GSSName representing the indicated principal
     *
     * @see GSSName
     * @see GSSName#NT_EXPORT_NAME
     *
     * @throws GSSException containing the following
     * major error codes:
     *    {@link GSSException#BAD_NAMETYPE GSSException.BAD_NAMETYPE},
     *    {@link GSSException#BAD_NAME GSSException.BAD_NAME},
     *    {@link GSSException#BAD_MECH GSSException.BAD_MECH},
     *    {@link GSSException#FAILURE GSSException.FAILURE}
     */
    public abstract GSSName createName(byte name[], Oid nameType)
        throws GSSException;

    
 Factory method to convert a string name from the specified namespace to a GSSName object and canonicalize it at the same time for a mechanism. In other words, this method is a utility that does the equivalent of two steps: the createName and then also the GSSName.canonicalize. 
Params:
  • nameStr – the string representing a printable form of the name to
create.
  • nameType – the Oid specifying the namespace of the printable name
supplied. null can be used to specify
that a mechanism specific default printable syntax should
be assumed by each mechanism that examines nameStr.
It is not advisable to use the nametype NT_EXPORT_NAME with this
method.
  • mech – Oid specifying the mechanism for which the name should be
canonicalized
Throws:
See Also:
Returns:a GSSName representing the indicated principal
/**
     *  Factory method to convert a string name from the
     * specified namespace to a GSSName object and canonicalize it at the
     * same time for a mechanism. In other words, this method is
     * a utility that does the equivalent of two steps: the {@link
     * #createName(String, Oid) createName} and then also the {@link
     * GSSName#canonicalize(Oid) GSSName.canonicalize}.
     *
     * @param nameStr the string representing a printable form of the name to
     * create.
     * @param nameType the Oid specifying the namespace of the printable name
     * supplied. <code>null</code> can be used to specify
     * that a mechanism specific default printable syntax should
     * be assumed by each mechanism that examines nameStr.
     * It is not advisable to use the nametype NT_EXPORT_NAME with this
     * method.
     * @param mech Oid specifying the mechanism for which the name should be
     * canonicalized
     * @return a GSSName representing the indicated principal
     *
     * @see GSSName#canonicalize(Oid)
     * @see GSSName#NT_EXPORT_NAME
     *
     * @throws GSSException containing the following
     * major error codes:
     *    {@link GSSException#BAD_NAMETYPE GSSException.BAD_NAMETYPE},
     *    {@link GSSException#BAD_NAME GSSException.BAD_NAME},
     *    {@link GSSException#BAD_MECH GSSException.BAD_MECH},
     *    {@link GSSException#FAILURE GSSException.FAILURE}
     */
    public abstract GSSName createName(String nameStr, Oid nameType,
                                       Oid mech) throws GSSException;

    
 Factory method to convert a byte array containing a name from the specified namespace to a GSSName object and canonicalize it at the same time for a mechanism. In other words, this method is a utility that does the equivalent of two steps: the createName and then also GSSName.canonicalize. 
Params:
  • name – the byte array containing the name to create
  • nameType – the Oid specifying the namespace of the name supplied
in the byte array. null can be used to specify that a
mechanism specific default syntax should be assumed by each mechanism
that examines the byte array.
  • mech – Oid specifying the mechanism for which the name should be
canonicalized
Throws:
See Also:
Returns:a GSSName representing the indicated principal
/**
     *  Factory method to convert a byte array containing a
     * name from the specified namespace to a GSSName object and canonicalize
     * it at the same time for a mechanism. In other words, this method is a
     * utility that does the equivalent of two steps: the {@link
     * #createName(byte[], Oid) createName} and then also {@link
     * GSSName#canonicalize(Oid) GSSName.canonicalize}.
     *
     * @param name the byte array containing the name to create
     * @param nameType the Oid specifying the namespace of the name supplied
     * in the byte array. <code>null</code> can be used to specify that a
     * mechanism specific default syntax should be assumed by each mechanism
     * that examines the byte array.
     * @param mech Oid specifying the mechanism for which the name should be
     * canonicalized
     * @return a GSSName representing the indicated principal
     *
     * @see GSSName#canonicalize(Oid)
     * @see GSSName#NT_EXPORT_NAME
     *
     * @throws GSSException containing the following
     * major error codes:
     *    {@link GSSException#BAD_NAMETYPE GSSException.BAD_NAMETYPE},
     *    {@link GSSException#BAD_NAME GSSException.BAD_NAME},
     *    {@link GSSException#BAD_MECH GSSException.BAD_MECH},
     *    {@link GSSException#FAILURE GSSException.FAILURE}
     */
    public abstract GSSName createName(byte name[], Oid nameType, Oid mech)
        throws GSSException;

    
Factory method for acquiring default credentials.  This will cause
the GSS-API to use system specific defaults for the set of mechanisms,
name, and lifetime.
 GSS-API mechanism providers must impose a local access-control policy on callers to prevent unauthorized callers from acquiring credentials to which they are not entitled. The kinds of permissions needed by different mechanism providers will be documented on a per-mechanism basis. A failed permission check might cause a SecurityException to be thrown from this method. 
Params:
Throws:
See Also:
Returns:a GSSCredential of the requested type.
/**
     * Factory method for acquiring default credentials.  This will cause
     * the GSS-API to use system specific defaults for the set of mechanisms,
     * name, and lifetime.<p>
     *
     * GSS-API mechanism providers must impose a local access-control
     * policy on callers to prevent unauthorized callers from acquiring
     * credentials to which they are not entitled. The kinds of permissions
     * needed by different mechanism providers will be documented on a
     * per-mechanism basis. A failed permission check might cause a {@link
     * java.lang.SecurityException SecurityException} to be thrown from
     * this method.
     *
     * @param usage The intended usage for this credential object. The value
     * of this parameter must be one of:
     * {@link GSSCredential#INITIATE_AND_ACCEPT
     * GSSCredential.INITIATE_AND_ACCEPT},
     * {@link GSSCredential#ACCEPT_ONLY GSSCredential.ACCEPT_ONLY}, and
     * {@link GSSCredential#INITIATE_ONLY GSSCredential.INITIATE_ONLY}.
     * @return a GSSCredential of the requested type.
     *
     * @see GSSCredential
     *
     * @throws GSSException containing the following
     * major error codes:
     *    {@link GSSException#BAD_MECH GSSException.BAD_MECH},
     *    {@link GSSException#BAD_NAMETYPE GSSException.BAD_NAMETYPE},
     *    {@link GSSException#BAD_NAME GSSException.BAD_NAME},
     *    {@link GSSException#CREDENTIALS_EXPIRED
     *                                   GSSException.CREDENTIALS_EXPIRED},
     *    {@link GSSException#NO_CRED GSSException.NO_CRED},
     *    {@link GSSException#FAILURE GSSException.FAILURE}
     */
    public abstract GSSCredential createCredential (int usage)
        throws GSSException;

    
Factory method for acquiring a single mechanism credential.
 GSS-API mechanism providers must impose a local access-control policy on callers to prevent unauthorized callers from acquiring credentials to which they are not entitled. The kinds of permissions needed by different mechanism providers will be documented on a per-mechanism basis. A failed permission check might cause a SecurityException to be thrown from this method. 
 Non-default values for lifetime cannot always be honored by the underlying mechanisms, thus applications should be prepared to call getRemainingLifetime on the returned credential.


Params:
Throws:
See Also:
Returns:a GSSCredential of the requested type.
/**
     * Factory method for acquiring a single mechanism credential.<p>
     *
     * GSS-API mechanism providers must impose a local access-control
     * policy on callers to prevent unauthorized callers from acquiring
     * credentials to which they are not entitled. The kinds of permissions
     * needed by different mechanism providers will be documented on a
     * per-mechanism basis. A failed permission check might cause a {@link
     * java.lang.SecurityException SecurityException} to be thrown from
     * this method. <p>
     *
     * Non-default values for lifetime cannot always be honored by the
     * underlying mechanisms, thus applications should be prepared to call
     * {@link GSSCredential#getRemainingLifetime() getRemainingLifetime}
     * on the returned credential.<p>
     *
     * @param name the name of the principal for whom this credential is to be
     * acquired.  Use <code>null</code> to specify the default principal.
     * @param lifetime The number of seconds that credentials should remain
     * valid.  Use {@link GSSCredential#INDEFINITE_LIFETIME
     * GSSCredential.INDEFINITE_LIFETIME} to request that the credentials
     * have the maximum permitted lifetime.  Use {@link
     * GSSCredential#DEFAULT_LIFETIME GSSCredential.DEFAULT_LIFETIME} to
     * request default credential lifetime.
     * @param mech the Oid of the desired mechanism.  Use <code>(Oid) null
     * </code> to request the default mechanism.
     * @param usage The intended usage for this credential object. The value
     * of this parameter must be one of:
     * {@link GSSCredential#INITIATE_AND_ACCEPT
     * GSSCredential.INITIATE_AND_ACCEPT},
     * {@link GSSCredential#ACCEPT_ONLY GSSCredential.ACCEPT_ONLY}, and
     * {@link GSSCredential#INITIATE_ONLY GSSCredential.INITIATE_ONLY}.
     * @return a GSSCredential of the requested type.
     *
     * @see GSSCredential
     *
     * @throws GSSException containing the following
     * major error codes:
     *    {@link GSSException#BAD_MECH GSSException.BAD_MECH},
     *    {@link GSSException#BAD_NAMETYPE GSSException.BAD_NAMETYPE},
     *    {@link GSSException#BAD_NAME GSSException.BAD_NAME},
     *    {@link GSSException#CREDENTIALS_EXPIRED
     *                                   GSSException.CREDENTIALS_EXPIRED},
     *    {@link GSSException#NO_CRED GSSException.NO_CRED},
     *    {@link GSSException#FAILURE GSSException.FAILURE}
     */
    public abstract GSSCredential createCredential (GSSName name,
                                  int lifetime, Oid mech, int usage)
        throws GSSException;

    
Factory method for acquiring credentials over a set of mechanisms. This method attempts to acquire credentials for each of the mechanisms specified in the array called mechs. To determine the list of mechanisms for which the acquisition of credentials succeeded, the caller should use the GSSCredential.getMechs method.
 GSS-API mechanism providers must impose a local access-control policy on callers to prevent unauthorized callers from acquiring credentials to which they are not entitled. The kinds of permissions needed by different mechanism providers will be documented on a per-mechanism basis. A failed permission check might cause a SecurityException to be thrown from this method.
 Non-default values for lifetime cannot always be honored by the underlying mechanisms, thus applications should be prepared to call getRemainingLifetime on the returned credential.


Params:
Throws:
See Also:
Returns:a GSSCredential of the requested type.
/**
     * Factory method for acquiring credentials over a set of
     * mechanisms. This method attempts to acquire credentials for
     * each of the mechanisms specified in the array called mechs.  To
     * determine the list of mechanisms for which the acquisition of
     * credentials succeeded, the caller should use the {@link
     * GSSCredential#getMechs() GSSCredential.getMechs} method.<p>
     *
     * GSS-API mechanism providers must impose a local access-control
     * policy on callers to prevent unauthorized callers from acquiring
     * credentials to which they are not entitled. The kinds of permissions
     * needed by different mechanism providers will be documented on a
     * per-mechanism basis. A failed permission check might cause a {@link
     * java.lang.SecurityException SecurityException} to be thrown from
     * this method.<p>
     *
     * Non-default values for lifetime cannot always be honored by the
     * underlying mechanisms, thus applications should be prepared to call
     * {@link GSSCredential#getRemainingLifetime() getRemainingLifetime}
     * on the returned credential.<p>
     *
     * @param name the name of the principal for whom this credential is to
     * be acquired.  Use <code>null</code> to specify the default
     * principal.
     * @param lifetime The number of seconds that credentials should remain
     * valid.  Use {@link GSSCredential#INDEFINITE_LIFETIME
     * GSSCredential.INDEFINITE_LIFETIME} to request that the credentials
     * have the maximum permitted lifetime.  Use {@link
     * GSSCredential#DEFAULT_LIFETIME GSSCredential.DEFAULT_LIFETIME} to
     * request default credential lifetime.
     * @param mechs an array of Oid's indicating the mechanisms over which
     * the credential is to be acquired.  Use <code>(Oid[]) null</code> for
     * requesting a system specific default set of mechanisms.
     * @param usage The intended usage for this credential object. The value
     * of this parameter must be one of:
     * {@link GSSCredential#INITIATE_AND_ACCEPT
     * GSSCredential.INITIATE_AND_ACCEPT},
     * {@link GSSCredential#ACCEPT_ONLY GSSCredential.ACCEPT_ONLY}, and
     * {@link GSSCredential#INITIATE_ONLY GSSCredential.INITIATE_ONLY}.
     * @return a GSSCredential of the requested type.
     *
     * @see GSSCredential
     *
     * @throws GSSException containing the following
     * major error codes:
     *    {@link GSSException#BAD_MECH GSSException.BAD_MECH},
     *    {@link GSSException#BAD_NAMETYPE GSSException.BAD_NAMETYPE},
     *    {@link GSSException#BAD_NAME GSSException.BAD_NAME},
     *    {@link GSSException#CREDENTIALS_EXPIRED
     *                                   GSSException.CREDENTIALS_EXPIRED},
     *    {@link GSSException#NO_CRED GSSException.NO_CRED},
     *    {@link GSSException#FAILURE GSSException.FAILURE}
     */
    public abstract GSSCredential createCredential(GSSName name,
                                      int lifetime, Oid mechs[], int usage)
        throws GSSException;

    
Factory method for creating a context on the initiator's side. Some mechanism providers might require that the caller be granted permission to initiate a security context. A failed permission check might cause a SecurityException to be thrown from this method.
 Non-default values for lifetime cannot always be honored by the underlying mechanism, thus applications should be prepared to call getLifetime on the returned context.


Params:
  • peer – the name of the target peer.
  • mech – the Oid of the desired mechanism.  Use null
to request the default mechanism.
  • myCred – the credentials of the initiator.  Use
null to act as the default initiator principal.
  • lifetime – the lifetime, in seconds, requested for the context. Use 
GSSContext.INDEFINITE_LIFETIME to request that the context have the maximum permitted lifetime. Use 
GSSContext.DEFAULT_LIFETIME to request a default lifetime for the context.
Throws:
See Also:
Returns:an unestablished GSSContext
/**
     * Factory method for creating a context on the initiator's
     * side.
     *
     * Some mechanism providers might require that the caller be granted
     * permission to initiate a security context. A failed permission check
     * might cause a {@link java.lang.SecurityException SecurityException}
     * to be thrown from this method.<p>
     *
     * Non-default values for lifetime cannot always be honored by the
     * underlying mechanism, thus applications should be prepared to call
     * {@link GSSContext#getLifetime() getLifetime} on the returned
     * context.<p>
     *
     * @param peer the name of the target peer.
     * @param mech the Oid of the desired mechanism.  Use <code>null</code>
     * to request the default mechanism.
     * @param myCred the credentials of the initiator.  Use
     * <code>null</code> to act as the default initiator principal.
     * @param lifetime the lifetime, in seconds, requested for the
     * context. Use {@link GSSContext#INDEFINITE_LIFETIME
     * GSSContext.INDEFINITE_LIFETIME} to request that the context have the
     * maximum permitted lifetime. Use {@link GSSContext#DEFAULT_LIFETIME
     * GSSContext.DEFAULT_LIFETIME} to request a default lifetime for the
     * context.
     * @return an unestablished GSSContext
     *
     * @see GSSContext
     *
     * @throws GSSException containing the following
     * major error codes:
     *    {@link GSSException#NO_CRED GSSException.NO_CRED}
     *    {@link GSSException#CREDENTIALS_EXPIRED
     *                      GSSException.CREDENTIALS_EXPIRED}
     *    {@link GSSException#BAD_NAMETYPE GSSException.BAD_NAMETYPE}
     *    {@link GSSException#BAD_MECH GSSException.BAD_MECH}
     *    {@link GSSException#FAILURE GSSException.FAILURE}
     */
    public abstract GSSContext createContext(GSSName peer, Oid mech,
                                        GSSCredential myCred, int lifetime)
        throws GSSException;

   
Factory method for creating a context on the acceptor' side. The context's properties will be determined from the input token supplied to the accept method. Some mechanism providers might require that the caller be granted permission to accept a security context. A failed permission check might cause a SecurityException to be thrown from this method. 
Params:
  • myCred – the credentials for the acceptor.  Use
null to act as a default acceptor principal.
Throws:
See Also:
Returns:an unestablished GSSContext
/**
    * Factory method for creating a context on the acceptor' side.  The
    * context's properties will be determined from the input token supplied
    * to the accept method.
    *
    * Some mechanism providers might require that the caller be granted
    * permission to accept a security context. A failed permission check
    * might cause a {@link java.lang.SecurityException SecurityException}
    * to be thrown from this method.
    *
    * @param myCred the credentials for the acceptor.  Use
    * <code>null</code> to act as a default acceptor principal.
    * @return an unestablished GSSContext
    *
    * @see GSSContext
    *
    * @throws GSSException containing the following
    * major error codes:
    *    {@link GSSException#NO_CRED GSSException.NO_CRED}
    *    {@link GSSException#CREDENTIALS_EXPIRED
    *                        GSSException.CREDENTIALS_EXPIRED}
    *    {@link GSSException#BAD_MECH GSSException.BAD_MECH}
    *    {@link GSSException#FAILURE GSSException.FAILURE}
    */
    public abstract GSSContext createContext(GSSCredential myCred)
        throws GSSException;

    
Factory method for creating a previously exported context.  The
context properties will be determined from the input token and
cannot be modified through the set methods.
 Implementations are not required to support the inter-process transfer of security contexts. Before exporting a context, calling the GSSContext.isTransferable will indicate if the context is transferable. Calling this method in an implementation that does not support it will result in a GSSException with the error code GSSException.UNAVAILABLE. Some mechanism providers might require that the caller be granted permission to initiate or accept a security context. A failed permission check might cause a 
SecurityException to be thrown from this method. 
Params:
  • interProcessToken – the token previously emitted from the
export method.
Throws:
See Also:
Returns:the previously established GSSContext
/**
     * Factory method for creating a previously exported context.  The
     * context properties will be determined from the input token and
     * cannot be modified through the set methods.<p>
     *
     * Implementations are not required to support the inter-process
     * transfer of security contexts.  Before exporting a context, calling
     * the {@link GSSContext#isTransferable() GSSContext.isTransferable}
     * will indicate if the context is transferable. Calling this method in
     * an implementation that does not support it will result in a
     * <code>GSSException</code> with the error
     * code {@link GSSException#UNAVAILABLE GSSException.UNAVAILABLE}.
     *
     * Some mechanism providers might require that the caller be granted
     * permission to initiate or accept a security context. A failed
     * permission check might cause a {@link java.lang.SecurityException
     * SecurityException} to be thrown from this method.
     *
     * @param interProcessToken the token previously emitted from the
     * export method.
     * @return the previously established GSSContext
     *
     * @see GSSContext
     *
     * @throws GSSException containing the following
     * major error codes:
     *    {@link GSSException#NO_CONTEXT GSSException.NO_CONTEXT},
     *    {@link GSSException#DEFECTIVE_TOKEN GSSException.DEFECTIVE_TOKEN},
     *    {@link GSSException#UNAVAILABLE GSSException.UNAVAILABLE},
     *    {@link GSSException#UNAUTHORIZED GSSException.UNAUTHORIZED},
     *    {@link GSSException#FAILURE GSSException.FAILURE}
     */
    public abstract GSSContext createContext(byte [] interProcessToken)
        throws GSSException;

    
This method is used to indicate to the GSSManager that the
application would like a particular provider to be used ahead of all
others when support is desired for the given mechanism. When a value
of null is used instead of an Oid for the mechanism,
the GSSManager must use the indicated provider ahead of all others
no matter what the mechanism is. Only when the indicated provider
does not support the needed mechanism should the GSSManager move on
to a different provider.

Calling this method repeatedly preserves the older settings but
lowers them in preference thus forming an ordered list of provider
and Oid pairs that grows at the top.

Calling addProviderAtFront with a null Oid will remove
all previous preferences that were set for this provider in the
GSSManager instance. Calling addProviderAtFront with a non-null
Oid will remove any previous preference that was set
using this mechanism and this provider together.

If the GSSManager implementation does not support an SPI with a
pluggable provider architecture it should throw a GSSException with
the status code GSSException.UNAVAILABLE to indicate that the
operation is unavailable.

Suppose an application desired that the provider A always be checked
first when any mechanism is needed, it would call:


        GSSManager mgr = GSSManager.getInstance();
        // mgr may at this point have its own pre-configured list
        // of provider preferences. The following will prepend to
        // any such list:
        mgr.addProviderAtFront(A, null);


Now if it also desired that the mechanism of Oid m1 always be
obtained from the provider B before the previously set A was checked,
it would call:


        mgr.addProviderAtFront(B, m1);


The GSSManager would then first check with B if m1 was needed. In
case B did not provide support for m1, the GSSManager would continue
on to check with A.  If any mechanism m2 is needed where m2 is
different from m1 then the GSSManager would skip B and check with A
directly.

Suppose at a later time the following call is made to the same
GSSManager instance:


        mgr.addProviderAtFront(B, null)


then the previous setting with the pair (B, m1) is subsumed by this
and should be removed. Effectively the list of preferences now
becomes {(B, null), (A, null),
        ... //followed by the pre-configured list.

Please note, however, that the following call:

        mgr.addProviderAtFront(A, m3)


does not subsume the previous setting of (A, null) and the list will
effectively become {(A, m3), (B, null), (A, null), ...}

Params:
  • p – the provider instance that should be used whenever support
is needed for mech.
  • mech – the mechanism for which the provider is being set
Throws:
/**
     * This method is used to indicate to the GSSManager that the
     * application would like a particular provider to be used ahead of all
     * others when support is desired for the given mechanism. When a value
     * of null is used instead of an <code>Oid</code> for the mechanism,
     * the GSSManager must use the indicated provider ahead of all others
     * no matter what the mechanism is. Only when the indicated provider
     * does not support the needed mechanism should the GSSManager move on
     * to a different provider.<p>
     *
     * Calling this method repeatedly preserves the older settings but
     * lowers them in preference thus forming an ordered list of provider
     * and <code>Oid</code> pairs that grows at the top.<p>
     *
     * Calling addProviderAtFront with a null <code>Oid</code> will remove
     * all previous preferences that were set for this provider in the
     * GSSManager instance. Calling addProviderAtFront with a non-null
     * <code>Oid</code> will remove any previous preference that was set
     * using this mechanism and this provider together.<p>
     *
     * If the GSSManager implementation does not support an SPI with a
     * pluggable provider architecture it should throw a GSSException with
     * the status code GSSException.UNAVAILABLE to indicate that the
     * operation is unavailable.<p>
     *
     * Suppose an application desired that the provider A always be checked
     * first when any mechanism is needed, it would call:<p>
     * <pre>
     *         GSSManager mgr = GSSManager.getInstance();
     *         // mgr may at this point have its own pre-configured list
     *         // of provider preferences. The following will prepend to
     *         // any such list:
     *
     *         mgr.addProviderAtFront(A, null);
     * </pre>
     * Now if it also desired that the mechanism of Oid m1 always be
     * obtained from the provider B before the previously set A was checked,
     * it would call:<p>
     * <pre>
     *         mgr.addProviderAtFront(B, m1);
     * </pre>
     * The GSSManager would then first check with B if m1 was needed. In
     * case B did not provide support for m1, the GSSManager would continue
     * on to check with A.  If any mechanism m2 is needed where m2 is
     * different from m1 then the GSSManager would skip B and check with A
     * directly.<p>
     *
     * Suppose at a later time the following call is made to the same
     * GSSManager instance:<p>
     * <pre>
     *         mgr.addProviderAtFront(B, null)
     * </pre>
     * then the previous setting with the pair (B, m1) is subsumed by this
     * and should be removed. Effectively the list of preferences now
     * becomes {(B, null), (A, null),
     *         ... //followed by the pre-configured list.<p>
     *
     * Please note, however, that the following call:
     * <pre>
     *         mgr.addProviderAtFront(A, m3)
     * </pre>
     * does not subsume the previous setting of (A, null) and the list will
     * effectively become {(A, m3), (B, null), (A, null), ...}
     *
     * @param p the provider instance that should be used whenever support
     * is needed for mech.
     * @param mech the mechanism for which the provider is being set
     *
     * @throws GSSException containing the following
     * major error codes:
     *    {@link GSSException#UNAVAILABLE GSSException.UNAVAILABLE},
     *    {@link GSSException#FAILURE GSSException.FAILURE}
     */
    public abstract void addProviderAtFront(Provider p, Oid mech)
        throws GSSException;

    
This method is used to indicate to the GSSManager that the
application would like a particular provider to be used if no other
provider can be found that supports the given mechanism. When a value
of null is used instead of an Oid for the mechanism, the GSSManager
must use the indicated provider for any mechanism.

Calling this method repeatedly preserves the older settings but
raises them above newer ones in preference thus forming an ordered
list of providers and Oid pairs that grows at the bottom. Thus the
older provider settings will be utilized first before this one is.

If there are any previously existing preferences that conflict with
the preference being set here, then the GSSManager should ignore this
request.

If the GSSManager implementation does not support an SPI with a
pluggable provider architecture it should throw a GSSException with
the status code GSSException.UNAVAILABLE to indicate that the
operation is unavailable.

Suppose an application desired that when a mechanism of Oid m1 is
needed the system default providers always be checked first, and only
when they do not support m1 should a provider A be checked. It would
then make the call:


        GSSManager mgr = GSSManager.getInstance();
        mgr.addProviderAtEnd(A, m1);


Now, if it also desired that for all mechanisms the provider B be
checked after all configured providers have been checked, it would
then call:


        mgr.addProviderAtEnd(B, null);


Effectively the list of preferences now becomes {..., (A, m1), (B,
null)}.

Suppose at a later time the following call is made to the same
GSSManager instance:


        mgr.addProviderAtEnd(B, m2)


then the previous setting with the pair (B, null) subsumes this and
therefore this request should be ignored. The same would happen if a
request is made for the already existing pairs of (A, m1) or (B,
null).

Please note, however, that the following call:


        mgr.addProviderAtEnd(A, null)


is not subsumed by the previous setting of (A, m1) and the list will
effectively become {..., (A, m1), (B, null), (A, null)}

Params:
  • p – the provider instance that should be used whenever support
is needed for mech.
  • mech – the mechanism for which the provider is being set
Throws:
/**
     * This method is used to indicate to the GSSManager that the
     * application would like a particular provider to be used if no other
     * provider can be found that supports the given mechanism. When a value
     * of null is used instead of an Oid for the mechanism, the GSSManager
     * must use the indicated provider for any mechanism.<p>
     *
     * Calling this method repeatedly preserves the older settings but
     * raises them above newer ones in preference thus forming an ordered
     * list of providers and Oid pairs that grows at the bottom. Thus the
     * older provider settings will be utilized first before this one is.<p>
     *
     * If there are any previously existing preferences that conflict with
     * the preference being set here, then the GSSManager should ignore this
     * request.<p>
     *
     * If the GSSManager implementation does not support an SPI with a
     * pluggable provider architecture it should throw a GSSException with
     * the status code GSSException.UNAVAILABLE to indicate that the
     * operation is unavailable.<p>
     *
     * Suppose an application desired that when a mechanism of Oid m1 is
     * needed the system default providers always be checked first, and only
     * when they do not support m1 should a provider A be checked. It would
     * then make the call:<p>
     * <pre>
     *         GSSManager mgr = GSSManager.getInstance();
     *         mgr.addProviderAtEnd(A, m1);
     * </pre>
     * Now, if it also desired that for all mechanisms the provider B be
     * checked after all configured providers have been checked, it would
     * then call:<p>
     * <pre>
     *         mgr.addProviderAtEnd(B, null);
     * </pre>
     * Effectively the list of preferences now becomes {..., (A, m1), (B,
     * null)}.<p>
     *
     * Suppose at a later time the following call is made to the same
     * GSSManager instance:<p>
     * <pre>
     *         mgr.addProviderAtEnd(B, m2)
     * </pre>
     * then the previous setting with the pair (B, null) subsumes this and
     * therefore this request should be ignored. The same would happen if a
     * request is made for the already existing pairs of (A, m1) or (B,
     * null).<p>
     *
     * Please note, however, that the following call:<p>
     * <pre>
     *         mgr.addProviderAtEnd(A, null)
     * </pre>
     * is not subsumed by the previous setting of (A, m1) and the list will
     * effectively become {..., (A, m1), (B, null), (A, null)}
     *
     * @param p the provider instance that should be used whenever support
     * is needed for mech.
     * @param mech the mechanism for which the provider is being set
     *
     * @throws GSSException containing the following
     * major error codes:
     *    {@link GSSException#UNAVAILABLE GSSException.UNAVAILABLE},
     *    {@link GSSException#FAILURE GSSException.FAILURE}
     */
    public abstract void addProviderAtEnd(Provider p, Oid mech)
        throws GSSException;
}