/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.security.acl;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import org.jboss.security.authorization.Resource;
import org.jboss.security.identity.Identity;
import org.jboss.security.identity.plugins.IdentityFactory;
/**
* <p>
* Utility class used by the {@code ACL} implementation.
* </p>
*
* @author <a href="mailto:sguilhen@redhat.com">Stefan Guilhen</a>
*/
public class Util
{
/**
* <p>
* Returns a {@code String} representation of the specified resource. The format of this representation
* is as follows: {@code resource_fqn:resource_id}, where {@code resource_fqn} is the fully-qualified
* name of the resource class, and {@code resource_id} is the unique identifier of the resource.
* </p>
*
* @param resource the {@code Resource} to be converted.
* @return a {@code String} representation of the resource.
*/
public static String getResourceAsString(Resource resource)
{
String resourceString = null;
if (resource != null)
{
String resourceClass = resource.getClass().getCanonicalName();
resourceString = resourceClass + ":" + getResourceKey(resource);
}
return resourceString;
}
/**
* <p>
* Returns a {@code String} representation of the specified identity. The format of this representation
* is as follows: {@code identity_fqn:identity_name}, where {@code identity_fqn} is the fully-qualified
* name of the identity class, and {@code identity_name} is a {@code String} representing the name of
* the identity.
* </p>
*
* @param identity the {@code Identity} to be converted.
* @return a {@code String} representation of the identity.
*/
public static String getIdentityAsString(Identity identity)
{
String identityString = null;
if (identity != null)
identityString = identity.getClass().getCanonicalName() + ":" + identity.getName();
return identityString;
}
/**
* <p>
* Builds and returns an identity from the specified {@code String} representation. It parses the
* {@code identityString} argument, and passes the parsed identity class, and identity name to
* the {@code IdentityFactory} to retrieve an instance of {@code Identity}.
* </p>
*
* @param identityString a {@code String} representation of the identity to be created.
* @return the constructed {@code Identity} instance.
*/
public static Identity getIdentityFromString(String identityString)
{
Identity identity = null;
if (identityString != null)
{
String[] identityParts = identityString.split(":");
if (identityParts.length != 2)
throw new IllegalArgumentException("Malformed identity String: " + identityString);
try
{
identity = IdentityFactory.createIdentity(identityParts[0], identityParts[1]);
}
catch (Exception e)
{
throw new RuntimeException(e);
}
}
return identity;
}
/**
* <p>
* Obtains an {@code Object} that can represent the specified resource uniquely. It first tries to find
* a {@code Field} annotated with a {@code javax.persistence.Id} annotation. If such field is found, the
* method tries to read the field's value. If no annotated field is found, this method just tries to
* invoke a {@code getId()} method on the resource.
* </p>
*
* @param resource the {@code Resource} whose id is to be retrieved.
* @return an {@code Object} representing the resource's id, or {@code null} if no id could be found
* according to the rules used by this method for retrieving the resource's id.
*/
private static Object getResourceKey(Resource resource)
{
Class<? extends Resource> resourceClass = resource.getClass();
Object resourceKey = null;
// first search for a field with a javax.persistence.Id annotation.
for (Field field : resourceClass.getDeclaredFields())
{
if (field.getAnnotation(javax.persistence.Id.class) != null)
{
// found a field - try to get its value reflectively.
try
{
resourceKey = field.get(resource);
}
catch (Exception e)
{
// in case of error, try executing the field getter method.
String fieldName = field.getName();
String methodName = "get" + fieldName.substring(0, 1).toUpperCase() + fieldName.substring(1);
resourceKey = executeNoArgMethod(resource, methodName);
}
break;
}
}
// if the above fails, try to simply locate a getId method.
if (resourceKey == null)
resourceKey = executeNoArgMethod(resource, "getId");
return resourceKey;
}
/**
* <p>
* Invokes a no-arg method reflectively in the specified target, and returns the result.
* </p>
*
* @param target the {@code Object} to be invoked.
* @param methodName a {@code String} representing the name of the method to be invoked.
* @return an {@code Object} containing the result of the invocation, or {@code null} if an
* the method is {@code void} or if an error occurs when invoking the method using reflection.
*/
@SuppressWarnings("all")
private static Object executeNoArgMethod(Object target, String methodName)
{
Class<?> targetClass = target.getClass();
try
{
Method method = targetClass.getMethod(methodName, null);
return method.invoke(target, null);
}
catch (Exception e)
{
// ignore exception and return null.
return null;
}
}
}