* It also supports trailing wildcards to allow the * easy granting of permissions in a hierarchical fashion. (For example, * the name "org.gnu.*" might grant all permissions under the "org.gnu" * permissions hierarchy). The only valid wildcard character is a '*' * which matches anything. It must be the rightmost element in the * permission name and must follow a '.' or else the Permission name must * consist of only a '*'. Any other occurrence of a '*' is not valid. *
* This class ignores the action list. Subclasses can choose to implement
* actions on top of this class if desired.
*
* @version 0.1
*
* @author Aaron M. Renn (arenn@urbanophile.com)
*/
public abstract class BasicPermission extends Permission implements Serializable
{
/*************************************************************************/
/*
* Constructors
*/
/**
* This method initializes a new instance of BasicPermission
* with the specified name. If the name contains an illegal wildcard
* character, an exception is thrown.
*
* @param name The name of this permission.
*
* @exception IllegalArgumentException If the name contains an invalid wildcard character
* @exception NullPointerException If the name is null
*/
public
BasicPermission(String name) throws IllegalArgumentException, NullPointerException
{
super(name);
if (name.indexOf("*") != -1)
{
if (!name.endsWith(".*") && !name.equals("*"))
throw new IllegalArgumentException("Bad wildcard: " + name);
if (name.indexOf("*") != name.lastIndexOf("*"))
throw new IllegalArgumentException("Bad wildcard: " + name);
}
}
/*************************************************************************/
/**
* This method initializes a new instance of BasicPermission
* with the specified name. If the name contains an illegal wildcard
* character, an exception is thrown. The action list passed to this
* form of the constructor is ignored.
*
* @param name The name of this permission.
* @param actions The list of actions for this permission - ignored in this class.
*
* @exception IllegalArgumentException If the name contains an invalid wildcard character
* @exception NullPointerException If the name is null
*/
public
BasicPermission(String name, String actions) throws IllegalArgumentException, NullPointerException
{
// ignore actions
this(name);
}
/*************************************************************************/
/**
* This method tests to see if the specified permission is implied by
* this permission. This will be true if the following conditions are met:
*
*
BasicPermission,
* or a subclass.
* Permission object to test against.
*
* @return true if the specified permission is implied by this one or false otherwise.
*/
public boolean
implies(Permission perm)
{
if (!(perm instanceof BasicPermission))
return false;
String otherName = perm.getName();
String name = getName();
if (name.equals(otherName))
return true;
int last = name.length() - 1;
if (name.charAt(last) == '*'
&& otherName.startsWith(name.substring(0, last)))
return true;
return false;
}
/*************************************************************************/
/**
* This method tests to see if this object is equal to the specified
* Object. This will be true if and only if the specified
* object meets the following conditions:
* *
BasicPermission, or a subclass.
* Object to test for equality against this object
*
* @return true if the specified Object is equal to this object or false otherwise.
*/
public boolean
equals(Object obj)
{
if (!(obj instanceof BasicPermission))
return(false);
if (!getName().equals(((BasicPermission)obj).getName()))
return(false);
return(true);
}
/*************************************************************************/
/**
* This method returns a hash code for this permission object. The hash
* code returned is the value returned by calling the hashCode
* method on the String that is the name of this permission.
*
* @return A hash value for this object
*/
public int
hashCode()
{
return(getName().hashCode());
}
/*************************************************************************/
/**
* This method returns a list of the actions associated with this
* permission. This method always returns the empty string ("") since
* this class ignores actions.
*
* @return The action list.
*/
public String
getActions()
{
return("");
}
/*************************************************************************/
/**
* This method returns an instance of PermissionCollection
* suitable for storing BasicPermission objects. This returns
* be a sub class of PermissionCollection
* that allows for an efficient and consistent implementation of
* the implies method. The collection doesn't handle subclasses
* of BasicPermission correctly; they must override this method.
*
* @return A new empty PermissionCollection object.
*/
public PermissionCollection
newPermissionCollection()
{
return new PermissionCollection()
{
Hashtable permissions = new Hashtable();
boolean allAllowed = false;
public void add(Permission permission)
{
if (isReadOnly())
throw new IllegalStateException("readonly");
BasicPermission bp = (BasicPermission) permission;
String name = bp.getName();
if (name.equals("*"))
allAllowed = true;
permissions.put(name, bp);
}
public boolean implies(Permission permission)
{
if (!(permission instanceof BasicPermission))
return false;
if (allAllowed)
return true;
BasicPermission toImply = (BasicPermission) permission;
String name = toImply.getName();
if (name.equals("*"))
return false;
int prefixLength = name.length();
if (name.endsWith("*"))
prefixLength -= 2;
while (true) {
if (permissions.get(name) != null)
return true;
prefixLength = name.lastIndexOf('.', prefixLength);
if (prefixLength < 0)
return false;
name = name.substring(0, prefixLength + 1) + '*';
}
}
public Enumeration elements()
{
return permissions.elements();
}
};
}
} // class BasicPermission