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ThreadGroup.java: Added synchronized flag to many methods.

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* ThreadGroup.java: Added synchronized flag to many methods.
	(destroyed_flag): Removed.
	(isDestroyed, removeGroup, removeThread): Test for parent == null.
	(activeCount): Added spec note.

From-SVN: r34750
This commit is contained in:
Bryce McKinlay 2000-06-28 06:03:11 +00:00 committed by Bryce McKinlay
parent d9984f96fc
commit 06772c7d0e
2 changed files with 51 additions and 36 deletions
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7
libjava/ChangeLog
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@ -1,3 +1,10 @@
2000-06-28 Bryce McKinlay <bryce@albatross.co.nz>
* ThreadGroup.java: Added synchronized flag to many methods.
(destroyed_flag): Removed.
(isDestroyed, removeGroup, removeThread): Test for parent == null.
(activeCount): Added spec note.
2000-06-27 Warren Levy <warrenl@cygnus.com> 2000-06-27 Warren Levy <warrenl@cygnus.com>
* java/security/Principal.java: New file. * java/security/Principal.java: New file.

80
libjava/java/lang/ThreadGroup.java
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@ -31,8 +31,8 @@ import java.util.Enumeration;
/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3 /* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
* "The Java Language Specification", ISBN 0-201-63451-1 * "The Java Language Specification", ISBN 0-201-63451-1
* plus online API docs for JDK 1.2 beta from http://www.javasoft.com. * plus online API docs for JDK 1.2 from http://www.javasoft.com.
* Status: Complete for 1.2. Parts from the JDK 1.0 spec only are * Status: Complete for 1.2. Some parts from the JDK 1.0 spec only are
* not implemented. * not implemented.
*/ */
@ -44,7 +44,8 @@ import java.util.Enumeration;
* *
* @author John Keiser * @author John Keiser
* @author Tom Tromey * @author Tom Tromey
* @version 1.2.0, June 20, 2000 * @author Bryce McKinlay
* @version 1.2.0
* @since JDK1.0 * @since JDK1.0
*/ */
@ -58,7 +59,6 @@ public class ThreadGroup
private Vector threads = new Vector(); private Vector threads = new Vector();
private Vector groups = new Vector(); private Vector groups = new Vector();
private boolean daemon_flag = false; private boolean daemon_flag = false;
private boolean destroyed_flag = false;
private int maxpri = Thread.MAX_PRIORITY; private int maxpri = Thread.MAX_PRIORITY;
private ThreadGroup() private ThreadGroup()
@ -87,7 +87,7 @@ public class ThreadGroup
{ {
parent.checkAccess(); parent.checkAccess();
this.parent = parent; this.parent = parent;
if (parent.destroyed_flag) if (parent.isDestroyed())
throw new IllegalArgumentException (); throw new IllegalArgumentException ();
this.name = name; this.name = name;
maxpri = parent.maxpri; maxpri = parent.maxpri;
@ -118,7 +118,7 @@ public class ThreadGroup
* @param maxpri the new maximum priority for this ThreadGroup. * @param maxpri the new maximum priority for this ThreadGroup.
* @exception SecurityException if you cannoy modify this ThreadGroup. * @exception SecurityException if you cannoy modify this ThreadGroup.
*/ */
public final void setMaxPriority(int maxpri) public final synchronized void setMaxPriority(int maxpri)
{ {
checkAccess(); checkAccess();
if (maxpri < this.maxpri if (maxpri < this.maxpri
@ -168,9 +168,9 @@ public class ThreadGroup
/** Tell whether this ThreadGroup has been destroyed or not. /** Tell whether this ThreadGroup has been destroyed or not.
* @return whether this ThreadGroup has been destroyed or not. * @return whether this ThreadGroup has been destroyed or not.
*/ */
public boolean isDestroyed() public synchronized boolean isDestroyed()
{ {
return destroyed_flag; return parent == null && this != root;
} }
/** Check whether this ThreadGroup is an ancestor of the /** Check whether this ThreadGroup is an ancestor of the
@ -200,6 +200,13 @@ public class ThreadGroup
* *
* @return the number of active threads in this ThreadGroup and * @return the number of active threads in this ThreadGroup and
* its descendants. * its descendants.
* @specnote it isn't clear what the definition of an "Active" thread is.
* Current JDKs regard all threads as active until they are
* finished, regardless of whether the thread has been started
* or not. We implement this behaviour.
* There is open JDC bug, <A HREF="http://developer.java.sun.com/developer/bugParade/bugs/4089701.html">
* 4089701</A>, regarding this issue.
*
*/ */
public synchronized int activeCount() public synchronized int activeCount()
{ {
@ -216,17 +223,17 @@ public class ThreadGroup
* itself is not included in the count. * itself is not included in the count.
* @specnote it is unclear what exactly constitutes an * @specnote it is unclear what exactly constitutes an
* active ThreadGroup. Currently we assume that * active ThreadGroup. Currently we assume that
* all sub-groups are active. * all sub-groups are active, per current JDKs.
* @return the number of active groups in this ThreadGroup. * @return the number of active groups in this ThreadGroup.
*/ */
public int activeGroupCount() public synchronized int activeGroupCount()
{ {
int total = groups.size(); int total = groups.size();
for (int i=0; i < groups.size(); i++) for (int i=0; i < groups.size(); i++)
{ {
ThreadGroup g = (ThreadGroup) groups.elementAt(i); ThreadGroup g = (ThreadGroup) groups.elementAt(i);
total += g.activeGroupCount(); total += g.activeGroupCount();
} }
return total; return total;
} }
@ -240,7 +247,7 @@ public class ThreadGroup
*/ */
public int enumerate(Thread[] threads) public int enumerate(Thread[] threads)
{ {
return enumerate(threads, true); return enumerate(threads, 0, true);
} }
/** Copy all of the active Threads from this ThreadGroup and, /** Copy all of the active Threads from this ThreadGroup and,
@ -259,7 +266,8 @@ public class ThreadGroup
} }
// This actually implements enumerate. // This actually implements enumerate.
private int enumerate (Thread[] list, int next_index, boolean recurse) private synchronized int enumerate(Thread[] list, int next_index,
boolean recurse)
{ {
Enumeration e = threads.elements(); Enumeration e = threads.elements();
while (e.hasMoreElements() && next_index < list.length) while (e.hasMoreElements() && next_index < list.length)
@ -286,7 +294,7 @@ public class ThreadGroup
*/ */
public int enumerate(ThreadGroup[] groups) public int enumerate(ThreadGroup[] groups)
{ {
return enumerate(groups, false); return enumerate(groups, 0, true);
} }
/** Copy all active ThreadGroups that are children of this /** Copy all active ThreadGroups that are children of this
@ -296,18 +304,19 @@ public class ThreadGroup
* ThreadGroups simply will not be copied. * ThreadGroups simply will not be copied.
* *
* @param groups the array to put the ThreadGroups into. * @param groups the array to put the ThreadGroups into.
* @param useDescendants whether to include all descendants * @param recurse whether to include all descendants
* of this ThreadGroup's children in determining * of this ThreadGroup's children in determining
* activeness. * activeness.
* @return the number of ThreadGroups copied into the array. * @return the number of ThreadGroups copied into the array.
*/ */
public int enumerate(ThreadGroup[] groups, boolean useDescendants) public int enumerate(ThreadGroup[] groups, boolean recurse)
{ {
return enumerate(groups, 0, useDescendants); return enumerate(groups, 0, recurse);
} }
// This actually implements enumerate. // This actually implements enumerate.
private int enumerate (ThreadGroup[] list, int next_index, boolean recurse) private synchronized int enumerate (ThreadGroup[] list, int next_index,
boolean recurse)
{ {
Enumeration e = groups.elements(); Enumeration e = groups.elements();
while (e.hasMoreElements() && next_index < list.length) while (e.hasMoreElements() && next_index < list.length)
@ -326,7 +335,7 @@ public class ThreadGroup
* ThreadGroups. * ThreadGroups.
* @since JDK1.2 * @since JDK1.2
*/ */
public final void interrupt() public final synchronized void interrupt()
{ {
checkAccess(); checkAccess();
for (int i=0; i < threads.size(); i++) for (int i=0; i < threads.size(); i++)
@ -347,7 +356,7 @@ public class ThreadGroup
* ThreadGroups. * ThreadGroups.
* @deprecated This method calls Thread.stop(), which is dangerous. * @deprecated This method calls Thread.stop(), which is dangerous.
*/ */
public final void stop() public final synchronized void stop()
{ {
checkAccess(); checkAccess();
for (int i=0; i<threads.size(); i++) for (int i=0; i<threads.size(); i++)
@ -368,7 +377,7 @@ public class ThreadGroup
* ThreadGroups. * ThreadGroups.
* @deprecated This method calls Thread.suspend(), which is dangerous. * @deprecated This method calls Thread.suspend(), which is dangerous.
*/ */
public final void suspend() public final synchronized void suspend()
{ {
checkAccess(); checkAccess();
for (int i=0; i<threads.size(); i++) for (int i=0; i<threads.size(); i++)
@ -389,7 +398,7 @@ public class ThreadGroup
* ThreadGroups. * ThreadGroups.
* @deprecated This method relies on Thread.suspend(), which is dangerous. * @deprecated This method relies on Thread.suspend(), which is dangerous.
*/ */
public final void resume() public final synchronized void resume()
{ {
checkAccess(); checkAccess();
for (int i=0; i < threads.size(); i++) for (int i=0; i < threads.size(); i++)
@ -405,7 +414,7 @@ public class ThreadGroup
} }
// This is a helper that is used to implement the destroy method. // This is a helper that is used to implement the destroy method.
private final void checkDestroy () private synchronized void checkDestroy ()
{ {
if (! threads.isEmpty()) if (! threads.isEmpty())
throw new IllegalThreadStateException ("ThreadGroup has threads"); throw new IllegalThreadStateException ("ThreadGroup has threads");
@ -425,15 +434,14 @@ public class ThreadGroup
* @exception SecurityException if you cannot modify this * @exception SecurityException if you cannot modify this
* ThreadGroup or any of its descendants. * ThreadGroup or any of its descendants.
*/ */
public final void destroy() public final synchronized void destroy()
{ {
checkAccess(); checkAccess();
if (destroyed_flag) if (isDestroyed())
throw new IllegalThreadStateException("Already destroyed."); throw new IllegalThreadStateException("Already destroyed.");
checkDestroy (); checkDestroy ();
if (parent != null) if (parent != null)
parent.removeGroup(this); parent.removeGroup(this);
destroyed_flag = true;
parent = null; parent = null;
for (int i=0; i < groups.size(); i++) for (int i=0; i < groups.size(); i++)
@ -450,7 +458,7 @@ public class ThreadGroup
list(""); list("");
} }
private final void list (String indentation) private synchronized void list(String indentation)
{ {
System.out.print(indentation); System.out.print(indentation);
System.out.println(toString ()); System.out.println(toString ());
@ -531,18 +539,18 @@ public class ThreadGroup
} }
// This is called to add a Thread to our internal list. // This is called to add a Thread to our internal list.
final void addThread(Thread t) final synchronized void addThread(Thread t)
{ {
if (destroyed_flag) if (isDestroyed())
throw new IllegalThreadStateException ("ThreadGroup is destroyed"); throw new IllegalThreadStateException ("ThreadGroup is destroyed");
threads.addElement(t); threads.addElement(t);
} }
// This is called to remove a Thread from our internal list. // This is called to remove a Thread from our internal list.
final void removeThread(Thread t) final synchronized void removeThread(Thread t)
{ {
if (destroyed_flag) if (isDestroyed())
throw new IllegalThreadStateException (); throw new IllegalThreadStateException ();
threads.removeElement(t); threads.removeElement(t);
@ -552,18 +560,18 @@ public class ThreadGroup
// We inline destroy to avoid the access check. // We inline destroy to avoid the access check.
if (parent != null) if (parent != null)
parent.removeGroup(this); parent.removeGroup(this);
destroyed_flag = true; parent = null;
} }
} }
// This is called to add a ThreadGroup to our internal list. // This is called to add a ThreadGroup to our internal list.
final void addGroup(ThreadGroup g) final synchronized void addGroup(ThreadGroup g)
{ {
groups.addElement(g); groups.addElement(g);
} }
// This is called to remove a ThreadGroup from our internal list. // This is called to remove a ThreadGroup from our internal list.
final void removeGroup(ThreadGroup g) final synchronized void removeGroup(ThreadGroup g)
{ {
groups.removeElement(g); groups.removeElement(g);
// Daemon groups are automatically destroyed when all their threads die. // Daemon groups are automatically destroyed when all their threads die.
@ -571,8 +579,8 @@ public class ThreadGroup
{ {
// We inline destroy to avoid the access check. // We inline destroy to avoid the access check.
if (parent != null) if (parent != null)
parent.removeGroup(this); parent.removeGroup(this);
destroyed_flag = true; parent = null;
} }
} }
} }