WebLogic Server 5.1.0 API Reference

weblogic.security.acl
Class FlatGroup

java.lang.Object
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  +--weblogic.security.acl.DefaultGroupImpl
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        +--weblogic.security.acl.FlatGroup

public abstract class FlatGroup

extends DefaultGroupImpl

Caching group implementation. Cooperates with classes that inherit from AbstractListableRealm, to provide a group implementation that remains up-to-date when its backing store changes.

FlatGroup attempts to avoid the problem of a Group object being created with a snapshot of the "real" group which is never afterwards updated. For example, if you store group information in a remote server and create a WebLogic ACL that refers to that group, the ACL will become out of date if the membership of that group ever changes on the remote server.

FlatGroup avoids that problem by maintaining its group membership in a cache, instead of a never-changing set. When the cache expires, this group implementation will query the realm that created it to obtain the most recent membership information. This query is performed by calling the FlatGroup.Source.getGroupMembers method (which is implemented by AsbtractListableRealm).

As a result of caching its membership information, a FlatGroup can occasionally become temporarily out-of-date with respect to its backing store, but this caching is necessary to maintain reasonable WebLogic Server performance.

By default, group membership information is cached for 5 minutes. If necessary, you can change this value by setting the weblogic.security.groupCacheTTL system property to the number of seconds you need (this value must be greater than zero).

Author:

Copyright (c) 2000 BEA Systems, Inc. All Rights Reserved.

See Also:

AbstractListableRealm

Inner Class Summary

static interface

FlatGroup.Source Interface to be implemented by realm classes that use FlatGroup.

Field Summary

protected java.util.Hashtable

members

Constructor Summary

protected	FlatGroup(java.lang.String name, FlatGroup.Source source) Create a new group, with no membership information.
protected	FlatGroup(java.lang.String name, FlatGroup.Source source, java.util.Hashtable members) Create a new group, with the given membership information.

Method Summary

protected boolean	addMemberInternal(java.security.Principal principal) Update this object's internal state when adding a member.
protected void	ensureFreshness() Important method for implementors.
boolean	equals(java.lang.Object obj)
static long	getCacheTTLMillis() Get the current group membership cache TTL, in milliseconds
protected abstract java.lang.Class	getUserClass() Return the class object used by users in this realm.
int	hashCode()
boolean	isMember(java.security.Principal member) Returns true if the passed principal is a member of the group.
java.util.Enumeration	members() Returns an enumeration of the members in the group.
protected boolean	removeMemberInternal(java.security.Principal principal) Update this object's internal state when removing a member.
protected static void	setCacheTTL(long millis) Set this group's membership cache TTL.
java.lang.String	toString()

Methods inherited from class weblogic.security.acl.DefaultGroupImpl

addMember, getName, removeMember

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

members

protected java.util.Hashtable members

Constructor Detail

FlatGroup

protected FlatGroup(java.lang.String name,
                    FlatGroup.Source source)

Create a new group, with no membership information. The membership cache won't be populated until the first relevant method is called.

FlatGroup

protected FlatGroup(java.lang.String name,
                    FlatGroup.Source source,
                    java.util.Hashtable members)

Create a new group, with the given membership information. The membership cache is immediately populated.

Method Detail

ensureFreshness

protected final void ensureFreshness()

Important method for implementors. If you override any methods in this class, you should call this method inside a synchronized(this) block before doing anything else, otherwise you risk group membership information being either out-of-date or completely nonexistent.

isMember

public boolean isMember(java.security.Principal member)

Returns true if the passed principal is a member of the group. This method does a recursive search, so if a principal belongs to a group which is a member of this group, true is returned.

Parameters:

member - the principal whose membership is to be checked.

Returns:

true if the principal is a member of this group, false otherwise.

Overrides:

isMember in class DefaultGroupImpl

members

public java.util.Enumeration members()

Returns an enumeration of the members in the group. The returned objects can be instances of either Principal or Group (which is a subclass of Principal).

Returns:

an enumeration of the group members.

Overrides:

members in class DefaultGroupImpl

toString

public java.lang.String toString()

Overrides:

toString in class DefaultGroupImpl

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

getUserClass

protected abstract java.lang.Class getUserClass()

Return the class object used by users in this realm. This is used to perform fast and safe membership checks.

addMemberInternal

protected boolean addMemberInternal(java.security.Principal principal)

Update this object's internal state when adding a member. You should call this if you write a new implementation of addMember, performing the call after your add succeeds.

removeMemberInternal

protected boolean removeMemberInternal(java.security.Principal principal)

Update this object's internal state when removing a member. You should call this if you write a new implementation of removeMember, performing the call after your remove succeeds.

setCacheTTL

protected static final void setCacheTTL(long millis)

Set this group's membership cache TTL. Note that this is a server-wide property, so changing this value will affect all objects that inherit from FlatGroup.

Parameters:

millis - new TTL, in milliseconds (must be positive)

getCacheTTLMillis

public static final long getCacheTTLMillis()

Get the current group membership cache TTL, in milliseconds