001: /*
002: * CoadunationLib: The coaduntion implementation library.
003: * Copyright (C) 2006 Rift IT Contracting
004: *
005: * This library is free software; you can redistribute it and/or
006: * modify it under the terms of the GNU Lesser General Public
007: * License as published by the Free Software Foundation; either
008: * version 2.1 of the License, or (at your option) any later version.
009: *
010: * This library is distributed in the hope that it will be useful,
011: * but WITHOUT ANY WARRANTY; without even the implied warranty of
012: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
013: * Lesser General Public License for more details.
014: *
015: * You should have received a copy of the GNU Lesser General Public
016: * License along with this library; if not, write to the Free Software
017: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
018: *
019: * InterceptorPermissionStack.java
020: *
021: * This class is responsible for keeping track of the thread permissions assigned
022: * to a thread and pushing and popping them to deal with threads being granted
023: * new permissions or releasing old permissions.
024: */
025:
026: // package path
027: package com.rift.coad.lib.interceptor;
028:
029: // java imports
030: import java.util.Stack;
031:
032: // logging import
033: import org.apache.log4j.Logger;
034:
035: // coadunation imports
036: import com.rift.coad.lib.security.ThreadsPermissionContainer;
037: import com.rift.coad.lib.security.ThreadPermissionSession;
038: import com.rift.coad.lib.security.UserSession;
039:
040: /**
041: * This class is responsible for keeping track of the thread permissions assigned
042: * to a thread and pushing and popping them to deal with threads being granted
043: * new permissions or releasing old permissions.
044: *
045: * @author Brett Chaldecott
046: */
047: public class InterceptorPermissionStack {
048:
049: // the class log variable
050: protected Logger log = Logger
051: .getLogger(InterceptorPermissionStack.class.getName());
052:
053: // private member variables
054: private ThreadsPermissionContainer permissionContainer = null;
055: private ThreadLocal threadLocal = new ThreadLocal();
056:
057: /**
058: * Creates a new instance of InterceptorPermissionStack
059: *
060: * @param permissionContainer The reference to the permission container
061: */
062: public InterceptorPermissionStack(
063: ThreadsPermissionContainer permissionContainer) {
064: this .permissionContainer = permissionContainer;
065: }
066:
067: /**
068: * This method pushes the current user session onto a stack so it can
069: * be popped back on when processing is completed.
070: *
071: * @param userSession The user session to apply to the current thread
072: * session.
073: * @exception InterceptorException
074: */
075: public void push(UserSession userSession)
076: throws InterceptorException {
077: try {
078: Stack stack = (Stack) threadLocal.get();
079: if (stack == null) {
080: stack = new Stack();
081: threadLocal.set(stack);
082: }
083: Thread currentThread = Thread.currentThread();
084: stack.push(permissionContainer.getSession(currentThread
085: .getId()));
086: permissionContainer.putSession(currentThread.getId(),
087: new ThreadPermissionSession(new Long(Thread
088: .currentThread().getId()), userSession));
089: } catch (Exception ex) {
090: log.error(
091: "Failed to push an entry on the interceptor permission "
092: + "stack : " + ex.getMessage(), ex);
093: }
094: }
095:
096: /**
097: * This method pops the user permissions of the stack and applies them to
098: * the current thread. Thus reveting them to the permissions that existed
099: * before the call on the push.
100: *
101: * @exception InterceptorException
102: */
103: public void pop() throws InterceptorException {
104: try {
105: Stack stack = (Stack) threadLocal.get();
106: if (stack == null) {
107: throw new InterceptorException(
108: "The interceptors are not getting used correctly there"
109: + "is not session for this thread.");
110: }
111: Thread currentThread = Thread.currentThread();
112: ThreadPermissionSession permission = (ThreadPermissionSession) stack
113: .pop();
114: if (permission != null) {
115: permissionContainer.putSession(currentThread.getId(),
116: permission);
117: } else {
118: permissionContainer
119: .removeSession(currentThread.getId());
120: }
121: } catch (InterceptorException ex) {
122: throw ex;
123: } catch (Exception ex) {
124: log.error(
125: "Failed to pop an entry off the interceptor permission "
126: + "stack : " + ex.getMessage(), ex);
127: }
128: }
129: }
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