/*
* Copyright © 2014 Cask Data, Inc.
*
* 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 co.cask.cdap.security;
import com.google.common.collect.Lists;
import java.security.Permission;
import java.security.PermissionCollection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
/**
* This class represents a collection of {@link Permission} objects.
* <p>
* With a {@link ApplicationPermissionCollection}, you can:
* <ul>
* <li>add a permission to the collection using the <code>add</code> method</li>
* <li>check to see if a particular permission is implied in the collection, using the <code>implies</code> method</li>
* <li>enumerate all the permission, using the <code>elements</code> method</li>
* </ul>
* </p>
* <p/>
* <p>
* This collection does not group the permissions, but these are collection of the permission
* related to an application that we want to restrict.
* </p>
*/
class ApplicationPermissionCollection extends PermissionCollection {
private final List<Permission> perms = Lists.newArrayList();
/**
* Constructor that defines some predefined {@link Permission}
*/
public ApplicationPermissionCollection() {
perms.add(new RuntimePermission("getenv.*"));
perms.add(new RuntimePermission("setContextClassLoader"));
}
/**
* Adds a {@link Permission} object to the current collection of permission objects.
*
* @param p the {@link Permission} object to be added.
*/
public void add(Permission p) {
synchronized (perms) {
perms.add(p);
}
}
/**
* Checks to see if the specified {@link Permission} <code>p</code> is implied by the collection
* of {@link Permission} objects held by the {@link ApplicationPermissionCollection}
*
* @param p the {@link Permission} object to compare.
* @return true if "permission" is implied by the permissions in the collection, false if not.
*/
public boolean implies(Permission p) {
Iterator<Permission> i = perms.iterator();
while (i.hasNext()) {
Permission p1 = ((Permission) i.next());
if (p.getClass().isAssignableFrom(p1.getClass()) && p1.implies(p)) {
return true;
}
}
return false;
}
/**
* @return an enumeration of all {@link Permission}s
*/
@Override
public Enumeration<Permission> elements() {
return Collections.enumeration(perms);
}
}