Java tutorial
/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.acegisecurity.vote; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.Iterator; import org.acegisecurity.Authentication; import org.acegisecurity.AuthorizationServiceException; import org.acegisecurity.ConfigAttribute; import org.acegisecurity.ConfigAttributeDefinition; import org.acegisecurity.acls.Acl; import org.acegisecurity.acls.AclService; import org.acegisecurity.acls.NotFoundException; import org.acegisecurity.acls.Permission; import org.acegisecurity.acls.objectidentity.ObjectIdentity; import org.acegisecurity.acls.objectidentity.ObjectIdentityRetrievalStrategy; import org.acegisecurity.acls.objectidentity.ObjectIdentityRetrievalStrategyImpl; import org.acegisecurity.acls.sid.Sid; import org.acegisecurity.acls.sid.SidRetrievalStrategy; import org.acegisecurity.acls.sid.SidRetrievalStrategyImpl; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.util.Assert; /** * <p>Given a domain object instance passed as a method argument, ensures the principal has appropriate permission * as indicated by the {@link AclService}.</p> * <p>The <code>AclService</code> is used to retrieve the access control list (ACL) permissions associated with a * domain object instance for the current <code>Authentication</code> object.</p> * <p>The voter will vote if any {@link ConfigAttribute#getAttribute()} matches the {@link * #processConfigAttribute}. The provider will then locate the first method argument of type {@link * #processDomainObjectClass}. Assuming that method argument is non-null, the provider will then lookup the ACLs from * the <code>AclManager</code> and ensure the principal is {@link Acl#isGranted(org.acegisecurity.acls.Permission[], * org.acegisecurity.acls.sid.Sid[], boolean)} when presenting the {@link #requirePermission} array to that method.</p> * <p>If the method argument is <code>null</code>, the voter will abstain from voting. If the method argument * could not be found, an {@link org.acegisecurity.AuthorizationServiceException} will be thrown.</p> * <p>In practical terms users will typically setup a number of <code>AclEntryVoter</code>s. Each will have a * different {@link #processDomainObjectClass}, {@link #processConfigAttribute} and {@link #requirePermission} * combination. For example, a small application might employ the following instances of <code>AclEntryVoter</code>: * <ul> * <li>Process domain object class <code>BankAccount</code>, configuration attribute * <code>VOTE_ACL_BANK_ACCONT_READ</code>, require permission <code>BasePermission.READ</code></li> * <li>Process domain object class <code>BankAccount</code>, configuration attribute * <code>VOTE_ACL_BANK_ACCOUNT_WRITE</code>, require permission list <code>BasePermission.WRITE</code> and * <code>BasePermission.CREATE</code> (allowing the principal to have <b>either</b> of these two permissions</li> * <li>Process domain object class <code>Customer</code>, configuration attribute * <code>VOTE_ACL_CUSTOMER_READ</code>, require permission <code>BasePermission.READ</code></li> * <li>Process domain object class <code>Customer</code>, configuration attribute * <code>VOTE_ACL_CUSTOMER_WRITE</code>, require permission list <code>BasePermission.WRITE</code> and * <code>BasePermission.CREATE</code></li> * </ul> * Alternatively, you could have used a common superclass or interface for the {@link #processDomainObjectClass} * if both <code>BankAccount</code> and <code>Customer</code> had common parents.</p> * <p>If the principal does not have sufficient permissions, the voter will vote to deny access.</p> * <p>All comparisons and prefixes are case sensitive.</p> * * @author Ben Alex * @version $Id: AclEntryVoter.java 1784 2007-02-24 21:00:24Z luke_t $ */ public class AclEntryVoter extends AbstractAclVoter { //~ Static fields/initializers ===================================================================================== private static final Log logger = LogFactory.getLog(AclEntryVoter.class); //~ Instance fields ================================================================================================ private AclService aclService; private ObjectIdentityRetrievalStrategy objectIdentityRetrievalStrategy = new ObjectIdentityRetrievalStrategyImpl(); private SidRetrievalStrategy sidRetrievalStrategy = new SidRetrievalStrategyImpl(); private String internalMethod; private String processConfigAttribute; private Permission[] requirePermission; //~ Constructors =================================================================================================== public AclEntryVoter(AclService aclService, String processConfigAttribute, Permission[] requirePermission) { Assert.notNull(processConfigAttribute, "A processConfigAttribute is mandatory"); Assert.notNull(aclService, "An AclService is mandatory"); if ((requirePermission == null) || (requirePermission.length == 0)) { throw new IllegalArgumentException("One or more requirePermission entries is mandatory"); } this.aclService = aclService; this.processConfigAttribute = processConfigAttribute; this.requirePermission = requirePermission; } //~ Methods ======================================================================================================== /** * Optionally specifies a method of the domain object that will be used to obtain a contained domain * object. That contained domain object will be used for the ACL evaluation. This is useful if a domain object * contains a parent that an ACL evaluation should be targeted for, instead of the child domain object (which * perhaps is being created and as such does not yet have any ACL permissions) * * @return <code>null</code> to use the domain object, or the name of a method (that requires no arguments) that * should be invoked to obtain an <code>Object</code> which will be the domain object used for ACL * evaluation */ public String getInternalMethod() { return internalMethod; } public String getProcessConfigAttribute() { return processConfigAttribute; } public void setInternalMethod(String internalMethod) { this.internalMethod = internalMethod; } public void setObjectIdentityRetrievalStrategy( ObjectIdentityRetrievalStrategy objectIdentityRetrievalStrategy) { Assert.notNull(objectIdentityRetrievalStrategy, "ObjectIdentityRetrievalStrategy required"); this.objectIdentityRetrievalStrategy = objectIdentityRetrievalStrategy; } public void setSidRetrievalStrategy(SidRetrievalStrategy sidRetrievalStrategy) { Assert.notNull(sidRetrievalStrategy, "SidRetrievalStrategy required"); this.sidRetrievalStrategy = sidRetrievalStrategy; } public boolean supports(ConfigAttribute attribute) { if ((attribute.getAttribute() != null) && attribute.getAttribute().equals(getProcessConfigAttribute())) { return true; } else { return false; } } public int vote(Authentication authentication, Object object, ConfigAttributeDefinition config) { Iterator iter = config.getConfigAttributes(); while (iter.hasNext()) { ConfigAttribute attr = (ConfigAttribute) iter.next(); if (this.supports(attr)) { // Need to make an access decision on this invocation // Attempt to locate the domain object instance to process Object domainObject = getDomainObjectInstance(object); // Evaluate if we are required to use an inner domain object if (domainObject != null && internalMethod != null && (!"".equals(internalMethod))) { try { Class clazz = domainObject.getClass(); Method method = clazz.getMethod(internalMethod, new Class[] {}); domainObject = method.invoke(domainObject, new Object[] {}); } catch (NoSuchMethodException nsme) { throw new AuthorizationServiceException("Object of class '" + domainObject.getClass() + "' does not provide the requested internalMethod: " + internalMethod); } catch (IllegalAccessException iae) { if (logger.isDebugEnabled()) { logger.debug("IllegalAccessException", iae); if (iae.getCause() != null) { logger.debug("Cause: " + iae.getCause().getMessage(), iae.getCause()); } } throw new AuthorizationServiceException("Problem invoking internalMethod: " + internalMethod + " for object: " + domainObject); } catch (InvocationTargetException ite) { if (logger.isDebugEnabled()) { logger.debug("InvocationTargetException", ite); if (ite.getCause() != null) { logger.debug("Cause: " + ite.getCause().getMessage(), ite.getCause()); } } throw new AuthorizationServiceException("Problem invoking internalMethod: " + internalMethod + " for object: " + domainObject); } } // If domain object is null, vote to abstain if (domainObject == null) { if (logger.isDebugEnabled()) { logger.debug("Voting to abstain - domainObject is null"); } return AccessDecisionVoter.ACCESS_ABSTAIN; } // Obtain the OID applicable to the domain object ObjectIdentity objectIdentity = objectIdentityRetrievalStrategy.getObjectIdentity(domainObject); // Obtain the SIDs applicable to the principal Sid[] sids = sidRetrievalStrategy.getSids(authentication); Acl acl; try { // Lookup only ACLs for SIDs we're interested in acl = aclService.readAclById(objectIdentity, sids); } catch (NotFoundException nfe) { if (logger.isDebugEnabled()) { logger.debug("Voting to deny access - no ACLs apply for this principal"); } return AccessDecisionVoter.ACCESS_DENIED; } try { if (acl.isGranted(requirePermission, sids, false)) { if (logger.isDebugEnabled()) { logger.debug("Voting to grant access"); } return AccessDecisionVoter.ACCESS_GRANTED; } else { if (logger.isDebugEnabled()) { logger.debug( "Voting to deny access - ACLs returned, but insufficient permissions for this principal"); } return AccessDecisionVoter.ACCESS_DENIED; } } catch (NotFoundException nfe) { if (logger.isDebugEnabled()) { logger.debug("Voting to deny access - no ACLs apply for this principal"); } return AccessDecisionVoter.ACCESS_DENIED; } } } // No configuration attribute matched, so abstain return AccessDecisionVoter.ACCESS_ABSTAIN; } }