java.lang.Objectjavax.security.auth.login.LoginContext
public class LoginContext
The LoginContext class describes the basic methods used to authenticate Subjects and provides a way to develop an application independent of the underlying authentication technology. A Configuration specifies the authentication technology, or LoginModule, to be used with a particular application. Different LoginModules can be plugged in under an application without requiring any modifications to the application itself.
In addition to supporting pluggable authentication, this class also supports the notion of stacked authentication. Applications may be configured to use more than one LoginModule. For example, one could configure both a Kerberos LoginModule and a smart card LoginModule under an application.
A typical caller instantiates a LoginContext with a name and a CallbackHandler. LoginContext uses the name as the index into a Configuration to determine which LoginModules should be used, and which ones must succeed in order for the overall authentication to succeed. The CallbackHandler is passed to the underlying LoginModules so they may communicate and interact with users (prompting for a username and password via a graphical user interface, for example).
Once the caller has instantiated a LoginContext, it invokes the login method to authenticate a Subject. The login method invokes the configured modules to perform their respective types of authentication (username/password, smart card pin verification, etc.). Note that the LoginModules will not attempt authentication retries nor introduce delays if the authentication fails. Such tasks belong to the LoginContext caller.
If the login method returns without throwing an exception, then the overall authentication succeeded. The caller can then retrieve the newly authenticated Subject by invoking the getSubject method. Principals and Credentials associated with the Subject may be retrieved by invoking the Subject's respective getPrincipals, getPublicCredentials, and getPrivateCredentials methods.
To logout the Subject, the caller calls the logout method. As with the login method, this logout method invokes the logout method for the configured modules.
A LoginContext should not be used to authenticate more than one Subject. A separate LoginContext should be used to authenticate each different Subject.
The following documentation applies to all LoginContext constructors:
If the constructor does not have a Configuration input parameter, or if the caller specifies a null Configuration object, the constructor uses the following call to get the installed Configuration:
config = Configuration.getConfiguration();For both cases, the name argument given to the constructor is passed to the Configuration.getAppConfigurationEntry method. If the Configuration has no entries for the specified name , then the LoginContext calls getAppConfigurationEntry with the name, " other " (the default entry name). If there is no entry for " other ", then a LoginException is thrown.
Note that Security Properties (such as auth.login.defaultCallbackHandler) can be set programmatically via the java.security.Security class, or statically in the Java security properties file located in the file named
<JAVA_HOME>/lib/security/java.security.
<JAVA_HOME>/lib/security/java.security, where
<JAVA_HOME> refers to the
value of the java.home system property, and specifies the
directory where the
JRE is
JDK was
installed.
Constructor Summary | |
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LoginContext
(
String
name) Instantiate a new LoginContext object with a name. |
|
LoginContext
(
String
name,
CallbackHandler
callbackHandler) Instantiate a new LoginContext object with a name and a CallbackHandler object. |
|
LoginContext
(
String
name,
Subject
subject) Instantiate a new LoginContext object with a name and a Subject object. |
|
LoginContext
(
String
name,
Subject
subject,
CallbackHandler
callbackHandler) Instantiate a new LoginContext object with a name, a Subject to be authenticated, and a CallbackHandler object. |
|
LoginContext
(
String
name,
Subject
subject,
CallbackHandler
callbackHandler,
Configuration
config) Instantiate a new LoginContext object with a name, a Subject to be authenticated, a CallbackHandler object, and a login Configuration. |
Method Summary | |
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Subject |
getSubject
() Return the authenticated Subject. |
void |
login
() Perform the authentication. |
void |
logout
() Logout the Subject. |
Methods inherited from class java.lang. Object |
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clone , equals , finalize , getClass , hashCode , notify , notifyAll , toString , wait , wait , wait |
Constructor Detail |
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public LoginContext(String name) throws LoginException
public LoginContext(String name, Subject subject) throws LoginException
public LoginContext(String name, CallbackHandler callbackHandler) throws LoginException
public LoginContext(String name, Subject subject, CallbackHandler callbackHandler) throws LoginException
public LoginContext(String name, Subject subject, CallbackHandler callbackHandler, Configuration config) throws LoginException
Method Detail |
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public void login() throws LoginException
This method invokes the login method for each LoginModule configured for the name specified to the LoginContext constructor, as determined by the login Configuration. Each LoginModule then performs its respective type of authentication (username/password, smart card pin verification, etc.).
This method completes a 2-phase authentication process by calling each configured LoginModule's commit method if the overall authentication succeeded (the relevant REQUIRED, REQUISITE, SUFFICIENT, and OPTIONAL LoginModules succeeded), or by calling each configured LoginModule's abort method if the overall authentication failed. If authentication succeeded, each successful LoginModule's commit method associates the relevant Principals and Credentials with the Subject. If authentication failed, each LoginModule's abort method removes/destroys any previously stored state.
If the commit phase of the authentication process fails, then the overall authentication fails and this method invokes the abort method for each configured LoginModule.
If the abort phase fails for any reason, then this method propagates the original exception thrown either during the login phase or the commit phase. In either case, the overall authentication fails.
In the case where multiple LoginModules fail, this method propagates the exception raised by the first LoginModule which failed.
Note that if this method enters the abort phase (either the login or commit phase failed), this method invokes all LoginModules configured for the application regardless of their respective Configuration flag parameters. Essentially this means that Requisite and Sufficient semantics are ignored during the abort phase. This guarantees that proper cleanup and state restoration can take place.
public void logout() throws LoginException
This method invokes the logout method for each LoginModule configured for this LoginContext. Each LoginModule performs its respective logout procedure which may include removing/destroying Principal and Credential information from the Subject and state cleanup.
Note that this method invokes all LoginModules configured for the application regardless of their respective Configuration flag parameters. Essentially this means that Requisite and Sufficient semantics are ignored for this method. This guarantees that proper cleanup and state restoration can take place.
public Subject getSubject()