/* BasicPermission.java -- implements a simple named permission
Copyright (C) 1998, 1999, 2002, 2003, 2004 Free Software Foundation, Inc.
This file is part of GNU Classpath.
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permission to link this library with independent modules to produce an
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package java.security;
import java.io.Serializable;
import java.util.Enumeration;
import java.util.Hashtable;
/**
* This class implements a simple model for named permissions without an
* associated action list. That is, either the named permission is granted
* or it is not.
*
* <p>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.
*
* <p>This class ignores the action list. Subclasses can choose to implement
* actions on top of this class if desired.
*
* @author Aaron M. Renn <arenn@urbanophile.com>
* @author Eric Blake <ebb9@email.byu.edu>
* @see Permission
* @see Permissions
* @see PermissionCollection
* @see RuntimePermission
* @see SecurityPermission
* @see PropertyPermission
* @see AWTPermission
* @see NetPermission
* @see SecurityManager
* @since 1.1
* @status updated to 1.4
*/
public abstract class BasicPermission extends java.security.Permission
implements Serializable
// FIXME extends with fully qualified classname as workaround for gcj 3.3.
{
/**
* Compatible with JDK 1.1+.
*/
private static final long serialVersionUID = 6279438298436773498L;
/**
* Create a new instance with the specified permission name. If the
* name is empty an exception is thrown.
*
* @param name the name of this permission
* @throws NullPointerException if name is null
* @throws IllegalArgumentException if name is invalid
*/
public BasicPermission(String name)
{
super(name);
// This routine used to check for illegal wildcards, but no such
// requirement exists in the specification and Sun's runtime
// doesn't appear to do it.
if ("".equals(name))
throw new IllegalArgumentException("Empty name");
}
/**
* Create a new instance with the specified permission name. If the name
* is empty, or contains an illegal wildcard character, an exception is
* thrown. The actions parameter is ignored.
*
* @param name the name of this permission
* @param actions ignored
* @throws NullPointerException if name is null
* @throws IllegalArgumentException if name is invalid
*/
public BasicPermission(String name, String 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:<ul>
* <li>The specified object is an instance of the same class as this
* object.</li>
* <li>The name of the specified permission is implied by this permission's
* name based on wildcard matching. For example, "a.*" implies "a.b".</li>
* </ul>
*
* @param perm the <code>Permission</code> object to test against
* @return true if the specified permission is implied
*/
public boolean implies(Permission perm)
{
if (! getClass().isInstance(perm))
return false;
String otherName = perm.getName();
String name = getName();
if (name.equals(otherName))
return true;
int last = name.length() - 1;
return name.charAt(last) == '*'
&& otherName.startsWith(name.substring(0, last));
}
/**
* This method tests to see if this object is equal to the specified
* <code>Object</code>. This will be true if and only if the specified
* object meets the following conditions:<ul>
* <li>It is an instance of the same class as this.</li>
* <li>It has the same name as this permission.</li>
* </ul>
*
* @param obj the <code>Object</code> to test for equality
* @return true if obj is semantically equal to this
*/
public boolean equals(Object obj)
{
return getClass().isInstance(obj)
&& getName().equals(((BasicPermission) obj).getName());
}
/**
* This method returns a hash code for this permission object. The hash
* code returned is the value returned by calling the <code>hashCode</code>
* method on the <code>String</code> 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 <code>PermissionCollection</code>
* suitable for storing <code>BasicPermission</code> objects. The
* collection returned can only store objects of the same type as this.
* Subclasses which use actions must override this method; but a class with
* no actions will work fine with this.
*
* @return a new empty <code>PermissionCollection</code> object
*/
public PermissionCollection newPermissionCollection()
{
return new BasicPermissionCollection(getClass());
}
} // class BasicPermission
/**
* Implements AllPermission.newPermissionCollection, and obeys serialization
* of JDK.
*
* @author Eric Blake <ebb9@email.byu.edu>
*/
final class BasicPermissionCollection extends PermissionCollection
{
/**
* Compatible with JDK 1.1+.
*/
private static final long serialVersionUID = 739301742472979399L;
/**
* The permissions in the collection.
*
* @serial a hash mapping name to permissions, all of type permClass
*/
private final Hashtable permissions = new Hashtable();
/**
* If "*" is in the collection.
*
* @serial true if a permission named "*" is in the collection
*/
private boolean all_allowed;
/**
* The runtime class which all entries in the table must belong to.
*
* @serial the limiting subclass of this collection
*/
private final Class permClass;
/**
* Construct a collection over the given runtime class.
*
* @param c the class
*/
BasicPermissionCollection(Class c)
{
permClass = c;
}
/**
* Add a Permission. It must be of the same type as the permission which
* created this collection.
*
* @param perm the permission to add
* @throws IllegalArgumentException if perm is not the correct type
* @throws SecurityException if the collection is read-only
*/
public void add(Permission perm)
{
if (isReadOnly())
throw new SecurityException("readonly");
if (! permClass.isInstance(perm))
throw new IllegalArgumentException("Expecting instance of " + permClass);
BasicPermission bp = (BasicPermission) perm;
String name = bp.getName();
if (name.equals("*"))
all_allowed = true;
permissions.put(name, bp);
}
/**
* Returns true if this collection implies the given permission.
*
* @param permission the permission to check
* @return true if it is implied by this
*/
public boolean implies(Permission permission)
{
if (! permClass.isInstance(permission))
return false;
if (all_allowed)
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) + '*';
}
}
/**
* Enumerate over the collection.
*
* @return an enumeration of the collection contents
*/
public Enumeration elements()
{
return permissions.elements();
}
} // class BasicPermissionCollection