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## javax.security.auth.login
Class Configuration

    java.lang.Object
      javax.security.auth.login.Configuration

    public abstract class Configuration

extends Object

This is an abstract class for representing the configuration of LoginModules under an application. The `Configuration` specifies which LoginModules should be used for a particular application, and in what order the LoginModules should be invoked. This abstract class needs to be subclassed to provide an implementation which reads and loads the actual `Configuration`.

A login configuration contains the following information. Note that this example only represents the default syntax for the `Configuration`. Subclass implementations of this class may implement alternative syntaxes and may retrieve the `Configuration` from any source such as files, databases, or servers.

          Name {
                  ModuleClass  Flag    ModuleOptions;
                  ModuleClass  Flag    ModuleOptions;
                  ModuleClass  Flag    ModuleOptions;
          };
          Name {
                  ModuleClass  Flag    ModuleOptions;
                  ModuleClass  Flag    ModuleOptions;
          };
          other {
                  ModuleClass  Flag    ModuleOptions;
                  ModuleClass  Flag    ModuleOptions;
          };

Each entry in the `Configuration` is indexed via an application name, Name, and contains a list of LoginModules configured for that application. Each `LoginModule` is specified via its fully qualified class name. Authentication proceeds down the module list in the exact order specified. If an application does not have specific entry, it defaults to the specific entry for "other".

The Flag value controls the overall behavior as authentication proceeds down the stack. The following represents a description of the valid values for Flag and their respective semantics:

          1) Required     - The LoginModule is required to succeed.
                            If it succeeds or fails, authentication still continues
                            to proceed down the LoginModule list.

          2) Requisite    - The LoginModule is required to succeed.
                            If it succeeds, authentication continues down the
                            LoginModule list.  If it fails,
                            control immediately returns to the application
                            (authentication does not proceed down the
                            LoginModule list).

          3) Sufficient   - The LoginModule is not required to
                            succeed.  If it does succeed, control immediately
                            returns to the application (authentication does not
                            proceed down the LoginModule list).
                            If it fails, authentication continues down the
                            LoginModule list.

          4) Optional     - The LoginModule is not required to
                            succeed.  If it succeeds or fails,
                            authentication still continues to proceed down the
                            LoginModule list.

The overall authentication succeeds only if all Required and Requisite LoginModules succeed. If a Sufficient `LoginModule` is configured and succeeds, then only the Required and Requisite LoginModules prior to that Sufficient `LoginModule` need to have succeeded for the overall authentication to succeed. If no Required or Requisite LoginModules are configured for an application, then at least one Sufficient or Optional `LoginModule` must succeed.

ModuleOptions is a space separated list of `LoginModule`-specific values which are passed directly to the underlying LoginModules. Options are defined by the `LoginModule` itself, and control the behavior within it. For example, a `LoginModule` may define options to support debugging/testing capabilities. The correct way to specify options in the `Configuration` is by using the following key-value pairing: debug="true". The key and value should be separated by an 'equals' symbol, and the value should be surrounded by double quotes. If a String in the form, ${system.property}, occurs in the value, it will be expanded to the value of the system property. Note that there is no limit to the number of options a `LoginModule` may define.

The following represents an example `Configuration` entry based on the syntax above:

     Login {
       com.sun.security.auth.module.UnixLoginModule required;
       com.sun.security.auth.module.Krb5LoginModule optional
                       useTicketCache="true"
                       ticketCache="${user.home}${/}tickets";
     };

This `Configuration` specifies that an application named, "Login", requires users to first authenticate to the com.sun.security.auth.module.UnixLoginModule, which is required to succeed. Even if the UnixLoginModule authentication fails, the com.sun.security.auth.module.Krb5LoginModule still gets invoked. This helps hide the source of failure. Since the Krb5LoginModule is Optional, the overall authentication succeeds only if the UnixLoginModule (Required) succeeds.

Also note that the LoginModule-specific options, useTicketCache="true" and ticketCache=${user.home}${/}tickets", are passed to the Krb5LoginModule. These options instruct the Krb5LoginModule to use the ticket cache at the specified location. The system properties, user.home and / (file.separator), are expanded to their respective values.

The default Configuration implementation can be changed by setting the value of the "login.configuration.provider" security property (in the Java security properties file) to the fully qualified name of the desired Configuration implementation class. The Java security properties file is located in the file named <JAVA_HOME>/lib/security/java.security, where <JAVA_HOME> refers to the directory where the JDK was installed.

See Also:
  `LoginContext`

Constructor Summary
`protected` | `Configuration()` Sole constructor.

Method Summary
`abstract AppConfigurationEntry[]` | `getAppConfigurationEntry(String name)` Retrieve the AppConfigurationEntries for the specified name from this Configuration.
`static Configuration` | `getConfiguration()` Get the Login Configuration.
`abstract void` | `refresh()` Refresh and reload the Configuration.
`static void` | `setConfiguration(Configuration configuration)` Set the Login `Configuration`.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### Configuration

    protected Configuration()

  Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Detail

### getConfiguration

    public static Configuration getConfiguration()

  Get the Login Configuration.

  Returns:
    the login Configuration. If a Configuration object was set via the `Configuration.setConfiguration` method, then that object is returned. Otherwise, a default Configuration object is returned.
  Throws:
    `SecurityException` - if the caller does not have permission to retrieve the Configuration.
  See Also:
    `setConfiguration(javax.security.auth.login.Configuration)`

### setConfiguration

    public static void setConfiguration(Configuration configuration)

  Set the Login `Configuration`.

  Parameters:
    `configuration` - the new `Configuration`
  Throws:
    `SecurityException` - if the current thread does not have Permission to set the `Configuration`.
  See Also:
    `getConfiguration()`

### getAppConfigurationEntry

    public abstract AppConfigurationEntry[] getAppConfigurationEntry(String name)

  Retrieve the AppConfigurationEntries for the specified name from this Configuration.

  Parameters:
    `name` - the name used to index the Configuration.
  Returns:
    an array of AppConfigurationEntries for the specified name from this Configuration, or null if there are no entries for the specified name

### refresh

    public abstract void refresh()

  Refresh and reload the Configuration.

  This method causes this Configuration object to refresh/reload its contents in an implementation-dependent manner. For example, if this Configuration object stores its entries in a file, calling `refresh` may cause the file to be re-read.

  Throws:
    `SecurityException` - if the caller does not have permission to refresh its Configuration.

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.