org.apache.river.api.security

Class ConcurrentPermissions

java.lang.Object

java.security.PermissionCollection

org.apache.river.api.security.ConcurrentPermissions

All Implemented Interfaces:

Serializable

final class ConcurrentPermissions
extends PermissionCollection
implements Serializable

ConcurrentPermissions is a drop in replacement for java.security.Permissions ConcurrentPermissions was originally intended to be used as a policy cache, it turns out that a policy cache was not needed, due to the efficiency of package private URIGrant.implies(ProtectionDomain pd). Scalability is better without a policy cache because PermissionGrant's are immutable, have no mutable shared state and are therefore not likely to cause cache misses. The first reason this class exists is due to an unknown bug in java.security.Permissions not resolving permission org.apache.river.phoenix.ExecOptionPermission "*"; in UnresolvedPermission. This occurs in start tests using Phoenix and defaultphoenix.policy in the qa suite. The second reason is performance tuning for concurrency or to avoid unnecessary collection resizing, a method in AbstractPolicy is provided so external policy providers can take advantage, without this class being public. This class may be removed in a future version of River. If there is heavy contention for one Permission class type, concurrency may suffer due to internal synchronization. This is due to the original PermissionsCollection spec requiring that all implementations do their own synchronization, this is a design mistake, similar to Vector. ConcurrentPermission's defined behaviour for #elements() differs from PermissionCollection. It is safe to alter ConcurrentPermissions while Enumerating through it's elements. ConcurrentPermission's keeps a cache of elements, but makes no guarantees that new elements will be added during an Enumeration. TODO: Serialization properly

Since:

3.0.0

Version:

0.5 2012/04/18

Author:

Peter Firmstone

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	ConcurrentPermissions.PC
private static class	ConcurrentPermissions.PermissionEnumerator
private static class	ConcurrentPermissions.PermissionPendingResolution
private static class	ConcurrentPermissions.PermissionPendingResolutionCollection

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	allPermission
private java.util.concurrent.ConcurrentMap<Class<?>,PermissionCollection>	permsMap
private static long	serialVersionUID
private ConcurrentPermissions.PermissionPendingResolutionCollection	unresolved

Constructor Summary

Constructors

Constructor and Description
ConcurrentPermissions()
ConcurrentPermissions(int initialCapacity, float loadFactor, int concurrencyLevel, int unresolvedClassCount)

Method Summary

Modifier and Type	Method and Description
void	add(Permission permission) Threadsafe
Enumeration<Permission>	elements() This Enumeration is not intended for concurrent access, modification of the underlying PermissionCollection will not cause a ConcurrentModificationException, but modifications made after this call returns may not be included in the Enumeration.
private PermissionCollection	getPC(Permission p)
boolean	implies(Permission permission) Returns true if Permission is implied for this PermissionDomain.

Methods inherited from class java.security.PermissionCollection

isReadOnly, setReadOnly, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

unresolved

private transient ConcurrentPermissions.PermissionPendingResolutionCollection unresolved

permsMap

private final java.util.concurrent.ConcurrentMap<Class<?>,PermissionCollection> permsMap

allPermission

private transient volatile boolean allPermission

Constructor Detail

ConcurrentPermissions

ConcurrentPermissions()

ConcurrentPermissions

ConcurrentPermissions(int initialCapacity,
                      float loadFactor,
                      int concurrencyLevel,
                      int unresolvedClassCount)

Method Detail

add

public void add(Permission permission)

Threadsafe

Specified by:

add in class PermissionCollection

Parameters:

permission -

getPC

private PermissionCollection getPC(Permission p)

implies

public boolean implies(Permission permission)

Returns true if Permission is implied for this PermissionDomain. Threadsafe this method is also a mutator method for internal state

Specified by:

implies in class PermissionCollection

Parameters:

permission -

Returns:

boolean

See Also:

Permission

elements

public Enumeration<Permission> elements()

This Enumeration is not intended for concurrent access, modification of the underlying PermissionCollection will not cause a ConcurrentModificationException, but modifications made after this call returns may not be included in the Enumeration. Any number of these Enumerations may be utilised , each accessed by a separate thread. This Enumeration may contain duplicates and it may contain UnresolvedPermission's as well as their resolved form.

Specified by:

elements in class PermissionCollection

Returns:

Enumeration