diff options
Diffstat (limited to 'libjava/java/lang/ThreadGroup.java')
| -rw-r--r-- | libjava/java/lang/ThreadGroup.java | 80 |
1 files changed, 44 insertions, 36 deletions
diff --git a/libjava/java/lang/ThreadGroup.java b/libjava/java/lang/ThreadGroup.java index 564c48d623e..f566e106f17 100644 --- a/libjava/java/lang/ThreadGroup.java +++ b/libjava/java/lang/ThreadGroup.java @@ -31,8 +31,8 @@ import java.util.Enumeration; /* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3 * "The Java Language Specification", ISBN 0-201-63451-1 - * plus online API docs for JDK 1.2 beta from http://www.javasoft.com. - * Status: Complete for 1.2. Parts from the JDK 1.0 spec only are + * plus online API docs for JDK 1.2 from http://www.javasoft.com. + * Status: Complete for 1.2. Some parts from the JDK 1.0 spec only are * not implemented. */ @@ -44,7 +44,8 @@ import java.util.Enumeration; * * @author John Keiser * @author Tom Tromey - * @version 1.2.0, June 20, 2000 + * @author Bryce McKinlay + * @version 1.2.0 * @since JDK1.0 */ @@ -58,7 +59,6 @@ public class ThreadGroup private Vector threads = new Vector(); private Vector groups = new Vector(); private boolean daemon_flag = false; - private boolean destroyed_flag = false; private int maxpri = Thread.MAX_PRIORITY; private ThreadGroup() @@ -87,7 +87,7 @@ public class ThreadGroup { parent.checkAccess(); this.parent = parent; - if (parent.destroyed_flag) + if (parent.isDestroyed()) throw new IllegalArgumentException (); this.name = name; maxpri = parent.maxpri; @@ -118,7 +118,7 @@ public class ThreadGroup * @param maxpri the new maximum priority for this ThreadGroup. * @exception SecurityException if you cannoy modify this ThreadGroup. */ - public final void setMaxPriority(int maxpri) + public final synchronized void setMaxPriority(int maxpri) { checkAccess(); if (maxpri < this.maxpri @@ -168,9 +168,9 @@ public class ThreadGroup /** Tell 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 @@ -200,6 +200,13 @@ public class ThreadGroup * * @return the number of active threads in this ThreadGroup and * 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() { @@ -216,17 +223,17 @@ public class ThreadGroup * itself is not included in the count. * @specnote it is unclear what exactly constitutes an * 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. */ - public int activeGroupCount() + public synchronized int activeGroupCount() { int total = groups.size(); for (int i=0; i < groups.size(); i++) { ThreadGroup g = (ThreadGroup) groups.elementAt(i); total += g.activeGroupCount(); - } + } return total; } @@ -240,7 +247,7 @@ public class ThreadGroup */ public int enumerate(Thread[] threads) { - return enumerate(threads, true); + return enumerate(threads, 0, true); } /** Copy all of the active Threads from this ThreadGroup and, @@ -259,7 +266,8 @@ public class ThreadGroup } // 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(); while (e.hasMoreElements() && next_index < list.length) @@ -286,7 +294,7 @@ public class ThreadGroup */ public int enumerate(ThreadGroup[] groups) { - return enumerate(groups, false); + return enumerate(groups, 0, true); } /** Copy all active ThreadGroups that are children of this @@ -296,18 +304,19 @@ public class ThreadGroup * ThreadGroups simply will not be copied. * * @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 * activeness. * @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. - 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(); while (e.hasMoreElements() && next_index < list.length) @@ -326,7 +335,7 @@ public class ThreadGroup * ThreadGroups. * @since JDK1.2 */ - public final void interrupt() + public final synchronized void interrupt() { checkAccess(); for (int i=0; i < threads.size(); i++) @@ -347,7 +356,7 @@ public class ThreadGroup * ThreadGroups. * @deprecated This method calls Thread.stop(), which is dangerous. */ - public final void stop() + public final synchronized void stop() { checkAccess(); for (int i=0; i<threads.size(); i++) @@ -368,7 +377,7 @@ public class ThreadGroup * ThreadGroups. * @deprecated This method calls Thread.suspend(), which is dangerous. */ - public final void suspend() + public final synchronized void suspend() { checkAccess(); for (int i=0; i<threads.size(); i++) @@ -389,7 +398,7 @@ public class ThreadGroup * ThreadGroups. * @deprecated This method relies on Thread.suspend(), which is dangerous. */ - public final void resume() + public final synchronized void resume() { checkAccess(); 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. - private final void checkDestroy () + private synchronized void checkDestroy () { if (! threads.isEmpty()) throw new IllegalThreadStateException ("ThreadGroup has threads"); @@ -425,15 +434,14 @@ public class ThreadGroup * @exception SecurityException if you cannot modify this * ThreadGroup or any of its descendants. */ - public final void destroy() + public final synchronized void destroy() { checkAccess(); - if (destroyed_flag) + if (isDestroyed()) throw new IllegalThreadStateException("Already destroyed."); checkDestroy (); if (parent != null) parent.removeGroup(this); - destroyed_flag = true; parent = null; for (int i=0; i < groups.size(); i++) @@ -450,7 +458,7 @@ public class ThreadGroup list(""); } - private final void list (String indentation) + private synchronized void list(String indentation) { System.out.print(indentation); System.out.println(toString ()); @@ -531,18 +539,18 @@ public class ThreadGroup } // 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"); threads.addElement(t); } // 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 (); threads.removeElement(t); @@ -552,18 +560,18 @@ public class ThreadGroup // We inline destroy to avoid the access check. if (parent != null) parent.removeGroup(this); - destroyed_flag = true; + parent = null; } } // 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); } // 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); // 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. if (parent != null) - parent.removeGroup(this); - destroyed_flag = true; + parent.removeGroup(this); + parent = null; } } } |