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public final class: AccessControlContext [javadoc | source]
An AccessControlContext is used to make system resource access decisions based on the context it encapsulates.

More specifically, it encapsulates a context and has a single method, checkPermission, that is equivalent to the checkPermission method in the AccessController class, with one difference: The AccessControlContext checkPermission method makes access decisions based on the context it encapsulates, rather than that of the current execution thread.

Thus, the purpose of AccessControlContext is for those situations where a security check that should be made within a given context actually needs to be done from within a different context (for example, from within a worker thread).

An AccessControlContext is created by calling the AccessController.getContext method. The getContext method takes a "snapshot" of the current calling context, and places it in an AccessControlContext object, which it returns. A sample call is the following:

  AccessControlContext acc = AccessController.getContext()

Code within a different context can subsequently call the checkPermission method on the previously-saved AccessControlContext object. A sample call is the following:

 public AccessControlContext(ProtectionDomain[] context) 
    Create an AccessControlContext with the given array of ProtectionDomains. Context must not be null. Duplicate domains will be removed from the context.
    context - the ProtectionDomains associated with this context. The non-duplicate domains are copied from the array. Subsequent changes to the array will not affect this AccessControlContext.
    NullPointerException - if context is null
 public AccessControlContext(AccessControlContext acc,
    DomainCombiner combiner) 
    Create a new AccessControlContext with the given AccessControlContext and DomainCombiner. This constructor associates the provided DomainCombiner with the provided AccessControlContext.

    acc - the AccessControlContext associated with the provided DomainCombiner.
    combiner - the DomainCombiner to be associated with the provided AccessControlContext.
    NullPointerException - if the provided context is null.
    SecurityException - if a security manager is installed and the caller does not have the "createAccessControlContext" SecurityPermission
    exception: NullPointerException - if the provided context is null.
    exception: SecurityException - if a security manager is installed and the caller does not have the "createAccessControlContext" SecurityPermission
    since: 1.3 -
 AccessControlContext(ProtectionDomain[] context,
    DomainCombiner combiner) 
    package private for AccessController
 AccessControlContext(ProtectionDomain[] context,
    boolean isPrivileged) 
    package private constructor for AccessController.getContext()
 AccessControlContext(ProtectionDomain[] context,
    AccessControlContext privilegedContext) 
    Constructor for JavaSecurityAccess.doIntersectionPrivilege()
Method from Summary:
checkPermission,   equals,   getAssignedCombiner,   getContext,   getDebug,   getDomainCombiner,   hashCode,   isPrivileged,   optimize
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from Detail:
 public  void checkPermission(Permission perm) throws AccessControlException 
    Determines whether the access request indicated by the specified permission should be allowed or denied, based on the security policy currently in effect, and the context in this object. The request is allowed only if every ProtectionDomain in the context implies the permission. Otherwise the request is denied.

    This method quietly returns if the access request is permitted, or throws a suitable AccessControlException otherwise.

 public boolean equals(Object obj) 
    Checks two AccessControlContext objects for equality. Checks that obj is an AccessControlContext and has the same set of ProtectionDomains as this context.

 DomainCombiner getAssignedCombiner() 
    get the assigned combiner from the privileged or inherited context
 ProtectionDomain[] getContext() 
    Returns this context's context.
 static Debug getDebug() 
 public DomainCombiner getDomainCombiner() 
    Get the DomainCombiner associated with this AccessControlContext.

 public int hashCode() 
    Returns the hash code value for this context. The hash code is computed by exclusive or-ing the hash code of all the protection domains in the context together.
 boolean isPrivileged() 
    Returns true if this context is privileged.
 AccessControlContext optimize() 
    Take the stack-based context (this) and combine it with the privileged or inherited context, if need be.