* A topic is a slash-separated string that defines a topic. *
* For example: * *
* org/osgi/service/foo/FooEvent/ACTION ** *
* TopicPermission has two actions: publish and
* subscribe.
*
* @version $Revision: 1.11 $
*/
public final class TopicPermission extends Permission {
static final long serialVersionUID = -5855563886961618300L;
/**
* The action string publish.
*/
public final static String PUBLISH = "publish"; //$NON-NLS-1$
/**
* The action string subscribe.
*/
public final static String SUBSCRIBE = "subscribe"; //$NON-NLS-1$
private final static int ACTION_PUBLISH = 0x00000001;
private final static int ACTION_SUBSCRIBE = 0x00000002;
private final static int ACTION_ALL = ACTION_PUBLISH
| ACTION_SUBSCRIBE;
private final static int ACTION_NONE = 0;
/**
* The actions mask.
*/
private transient int action_mask = ACTION_NONE;
/**
* prefix if the name is wildcarded.
*/
private transient String prefix;
/**
* The actions in canonical form.
*
* @serial
*/
private String actions = null;
/**
* Defines the authority to publich and/or subscribe to a topic within the
* EventAdmin service.
*
* The name is specified as a slash-separated string. Wildcards may be used. * For example: * *
* org/osgi/service/fooFooEvent/ACTION * com/isv/* * * ** *
* A bundle that needs to publish events on a topic must have the
* appropriate TopicPermission for that topic; similarly, a
* bundle that needs to subscribe to events on a topic must have the
* appropriate TopicPermssion for that topic.
*
*
* @param name Topic name.
* @param actions publish,subscribe
* (canonical order).
*/
public TopicPermission(String name, String actions) {
this(name, getMask(actions));
}
/**
* Package private constructor used by TopicPermissionCollection.
*
* @param name class name
* @param mask action mask
*/
TopicPermission(String name, int mask) {
super(name);
init(name, mask);
}
/**
* Called by constructors and when deserialized.
*
* @param name topic name
* @param mask action mask
*/
private void init(String name, int mask) {
if ((name == null) || name.length() == 0) {
throw new IllegalArgumentException("invalid name"); //$NON-NLS-1$
}
if (name.equals("*")) {
prefix = "";
}
else
if (name.endsWith("/*")) {
prefix = name.substring(0, name.length() - 1);
}
else {
prefix = null;
}
if ((mask == ACTION_NONE) || ((mask & ACTION_ALL) != mask)) {
throw new IllegalArgumentException("invalid action string"); //$NON-NLS-1$
}
action_mask = mask;
}
/**
* Parse action string into action mask.
*
* @param actions Action string.
* @return action mask.
*/
private static int getMask(String actions) {
boolean seencomma = false;
int mask = ACTION_NONE;
if (actions == null) {
return mask;
}
char[] a = actions.toCharArray();
int i = a.length - 1;
if (i < 0)
return mask;
while (i != -1) {
char c;
// skip whitespace
while ((i != -1)
&& ((c = a[i]) == ' ' || c == '\r' || c == '\n'
|| c == '\f' || c == '\t'))
i--;
// check for the known strings
int matchlen;
if (i >= 8 && (a[i - 8] == 's' || a[i - 8] == 'S')
&& (a[i - 7] == 'u' || a[i - 7] == 'U')
&& (a[i - 6] == 'b' || a[i - 6] == 'B')
&& (a[i - 5] == 's' || a[i - 5] == 'S')
&& (a[i - 4] == 'c' || a[i - 4] == 'C')
&& (a[i - 3] == 'r' || a[i - 3] == 'R')
&& (a[i - 2] == 'i' || a[i - 2] == 'I')
&& (a[i - 1] == 'b' || a[i - 1] == 'B')
&& (a[i] == 'e' || a[i] == 'E')) {
matchlen = 9;
mask |= ACTION_SUBSCRIBE;
}
else
if (i >= 6 && (a[i - 6] == 'p' || a[i - 6] == 'P')
&& (a[i - 5] == 'u' || a[i - 5] == 'U')
&& (a[i - 4] == 'b' || a[i - 4] == 'B')
&& (a[i - 3] == 'l' || a[i - 3] == 'L')
&& (a[i - 2] == 'i' || a[i - 2] == 'I')
&& (a[i - 1] == 's' || a[i - 1] == 'S')
&& (a[i] == 'h' || a[i] == 'H')) {
matchlen = 7;
mask |= ACTION_PUBLISH;
}
else {
// parse error
throw new IllegalArgumentException("invalid permission: " //$NON-NLS-1$
+ actions);
}
// make sure we didn't just match the tail of a word
// like "ackbarfpublish". Also, skip to the comma.
seencomma = false;
while (i >= matchlen && !seencomma) {
switch (a[i - matchlen]) {
case ',' :
seencomma = true;
/* FALLTHROUGH */
case ' ' :
case '\r' :
case '\n' :
case '\f' :
case '\t' :
break;
default :
throw new IllegalArgumentException(
"invalid permission: " + actions); //$NON-NLS-1$
}
i--;
}
// point i at the location of the comma minus one (or -1).
i -= matchlen;
}
if (seencomma) {
throw new IllegalArgumentException("invalid permission: " + actions); //$NON-NLS-1$
}
return mask;
}
/**
* Determines if the specified permission is implied by this object.
*
*
* This method checks that the topic name of the target is implied by the
* topic name of this object. The list of TopicPermission
* actions must either match or allow for the list of the target object to
* imply the target TopicPermission action.
*
*
* x/y/*,"publish" -> x/y/z,"publish" is true * *,"subscribe" -> x/y,"subscribe" is true * *,"publish" -> x/y,"subscribe" is false * x/y,"publish" -> x/y/z,"publish" is false ** * @param p The target permission to interrogate. * @return
true if the specified TopicPermission
* action is implied by this object; false otherwise.
*/
public boolean implies(Permission p) {
if (p instanceof TopicPermission) {
TopicPermission target = (TopicPermission) p;
if ((action_mask & target.action_mask) == target.action_mask) {
if (prefix != null) {
return target.getName().startsWith(prefix);
}
return target.getName().equals(getName());
}
}
return false;
}
/**
* Returns the canonical string representation of the
* TopicPermission actions.
*
*
* Always returns present TopicPermission actions in the
* following order: publish,subscribe.
*
* @return Canonical string representation of the
* TopicPermission actions.
*/
public String getActions() {
if (actions == null) {
StringBuffer sb = new StringBuffer();
boolean comma = false;
if ((action_mask & ACTION_PUBLISH) == ACTION_PUBLISH) {
sb.append(PUBLISH);
comma = true;
}
if ((action_mask & ACTION_SUBSCRIBE) == ACTION_SUBSCRIBE) {
if (comma)
sb.append(',');
sb.append(SUBSCRIBE);
}
actions = sb.toString();
}
return actions;
}
/**
* Returns a new PermissionCollection object suitable for
* storing TopicPermission objects.
*
* @return A new PermissionCollection object.
*/
public PermissionCollection newPermissionCollection() {
return new TopicPermissionCollection();
}
/**
* Determines the equality of two TopicPermission objects.
*
* This method checks that specified TopicPermission has the same topic name and
* actions as this
* TopicPermission object.
*
* @param obj The object to test for equality with this
* TopicPermission object.
* @return true if obj is a
* TopicPermission, and has the same topic name and
* actions as this TopicPermission object;
* false otherwise.
*/
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof TopicPermission)) {
return false;
}
TopicPermission p = (TopicPermission) obj;
return (action_mask == p.action_mask) && getName().equals(p.getName());
}
/**
* Returns the hash code value for this object.
*
* @return A hash code value for this object.
*/
public int hashCode() {
return getName().hashCode() ^ getActions().hashCode();
}
/**
* Returns the current action mask.
*
* Used by the TopicPermissionCollection class.
*
* @return Current action mask.
*/
int getMask() {
return action_mask;
}
/**
* WriteObject is called to save the state of this permission object to a
* stream. The actions are serialized, and the superclass takes care of the
* name.
*/
private synchronized void writeObject(java.io.ObjectOutputStream s)
throws IOException {
// Write out the actions. The superclass takes care of the name
// call getActions to make sure actions field is initialized
if (actions == null)
getActions();
s.defaultWriteObject();
}
/**
* readObject is called to restore the state of this permission from a
* stream.
*/
private synchronized void readObject(java.io.ObjectInputStream s)
throws IOException, ClassNotFoundException {
// Read in the action, then initialize the rest
s.defaultReadObject();
init(getName(), getMask(actions));
}
}
/**
* Stores a set of TopicPermission permissions.
*
* @see java.security.Permission
* @see java.security.Permissions
* @see java.security.PermissionCollection
*/
final class TopicPermissionCollection extends PermissionCollection {
static final long serialVersionUID = -614647783533924048L;
/**
* Table of permissions.
*
* @serial
*/
private Hashtable permissions;
/**
* Boolean saying if "*" is in the collection.
*
* @serial
*/
private boolean all_allowed;
/**
* Create an empty TopicPermissions object.
*
*/
public TopicPermissionCollection() {
permissions = new Hashtable();
all_allowed = false;
}
/**
* Adds a permission to the TopicPermission objects. The key
* for the hash is the name.
*
* @param permission The TopicPermission object to add.
*
* @throws IllegalArgumentException If the permission is not a
* TopicPermission instance.
*
* @throws SecurityException If this
* TopicPermissionCollection object has been
* marked read-only.
*/
public void add(Permission permission) {
if (!(permission instanceof TopicPermission))
throw new IllegalArgumentException("invalid permission: " //$NON-NLS-1$
+ permission);
if (isReadOnly())
throw new SecurityException("attempt to add a Permission to a " //$NON-NLS-1$
+ "readonly PermissionCollection"); //$NON-NLS-1$
TopicPermission pp = (TopicPermission) permission;
String name = pp.getName();
TopicPermission existing = (TopicPermission) permissions.get(name);
if (existing != null) {
int oldMask = existing.getMask();
int newMask = pp.getMask();
if (oldMask != newMask) {
permissions.put(name, new TopicPermission(name, oldMask
| newMask));
}
}
else {
permissions.put(name, permission);
}
if (!all_allowed) {
if (name.equals("*")) //$NON-NLS-1$
all_allowed = true;
}
}
/**
* Determines if the specified permissions implies the permissions expressed
* in permission.
*
* @param permission The Permission object to compare with this
* TopicPermission object.
*
* @return true if permission is a proper
* subset of a permission in the set; false
* otherwise.
*/
public boolean implies(Permission permission) {
if (!(permission instanceof TopicPermission))
return false;
TopicPermission pp = (TopicPermission) permission;
TopicPermission x;
int desired = pp.getMask();
int effective = 0;
// short circuit if the "*" Permission was added
if (all_allowed) {
x = (TopicPermission) permissions.get("*"); //$NON-NLS-1$
if (x != null) {
effective |= x.getMask();
if ((effective & desired) == desired)
return true;
}
}
// strategy:
// Check for full match first. Then work our way up the
// name looking for matches on a/b/*
String name = pp.getName();
x = (TopicPermission) permissions.get(name);
if (x != null) {
// we have a direct hit!
effective |= x.getMask();
if ((effective & desired) == desired)
return true;
}
// work our way up the tree...
int last, offset;
offset = name.length() - 1;
while ((last = name.lastIndexOf("/", offset)) != -1) { //$NON-NLS-1$
name = name.substring(0, last + 1) + "*"; //$NON-NLS-1$
x = (TopicPermission) permissions.get(name);
if (x != null) {
effective |= x.getMask();
if ((effective & desired) == desired)
return true;
}
offset = last - 1;
}
// we don't have to check for "*" as it was already checked
// at the top (all_allowed), so we just return false
return false;
}
/**
* Returns an enumeration of all TopicPermission objects in
* the container.
*
* @return Enumeration of all TopicPermission objects.
*/
public Enumeration elements() {
return permissions.elements();
}
}