Created an API for visiting the process tree

README.md

@@ -10,7 +10,7 @@ If you’re interested in adding support for a new platform, check out the proje
 Download latest
 ---------------
 
-The current version of JavaSysMon is 0.2.0, released December 28th. You can get it here: http://github.com/jezhumble/javasysmon/downloads
+The current version of JavaSysMon is 0.3.0, released January 8th. You can get it here: http://github.com/jezhumble/javasysmon/downloads
 
 Run it with java -jar
 
@@ -57,5 +57,6 @@ Links
 -----
 
 * Code: http://github.com/jezhumble/javasysmon
+* JavaDoc: http://jezhumble.github.com/javasysmon/
 * Bugs/Features: http://github.com/arya/javasysmon/issues
 * Mailing List: http://groups.google.com/group/javasysmon

src/main/java/com/jezhumble/javasysmon/JavaSysMon.java

@@ -232,8 +232,34 @@ public void killProcess(int pid) {
         monitor.killProcess(pid);
     }
 
-    public void killProcessTree(int pid, boolean descendantsOnly) {
-        processTree().find(pid).killTree(descendantsOnly);        
+    /**
+     * Allows you to visit the process tree, starting at the node identified by pid.
+     * The process tree is traversed depth-first.
+     * 
+     * @param pid The identifier of the node to start visiting
+     * @param processVisitor The visitor
+     */
+    public void visitProcessTree(final int pid, final ProcessVisitor processVisitor) {
+        processTree().find(pid).accept(processVisitor, 0);
+    }
+
+    /**
+     * Kills the process tree starting at the process identified by pid. The
+     * process tree is killed from the bottom up to ensure that orphans are
+     * not generated.
+     * <p>
+     * This method uses {@link #visitProcessTree}.
+     * 
+     * @param pid The identifier of the process at which to start killing the tree.
+     * @param descendantsOnly Whether or not to kill the process you start at,
+     * or only its descendants
+     */
+    public void killProcessTree(final int pid, final boolean descendantsOnly) {
+        visitProcessTree(pid, new ProcessVisitor() {
+            public boolean visit(OsProcess process, int level) {
+                return !descendantsOnly || (pid != process.processInfo().getPid());
+            }
+        });
     }
 
     /**

src/main/java/com/jezhumble/javasysmon/OsProcess.java

@@ -83,11 +83,18 @@ public OsProcess find(int pid) {
         return null;
     }
 
-    public void killTree(boolean descendantsOnly) {
+    /**
+     * Method to allow visiting the process tree. Use the convenience method
+     * {@link JavaSysMon#visitProcessTree}
+     *
+     * @param processVisitor An instance of {@link ProcessVisitor}
+     * @param level The level currently being visited
+     */
+    public void accept(ProcessVisitor processVisitor, int level) {
         for (Iterator it = children.iterator(); it.hasNext(); ) {
-            ((OsProcess) it.next()).killTree(false);
+            ((OsProcess) it.next()).accept(processVisitor, level + 1);
         }
-        if (!descendantsOnly) {
+        if (processVisitor.visit(this, level)) {
             new JavaSysMon().killProcess(processInfo.getPid());
         }
     }

src/main/java/com/jezhumble/javasysmon/ProcessVisitor.java

@@ -0,0 +1,14 @@
+package com.jezhumble.javasysmon;
+
+/**
+ * Allows you to visit the process tree using {@link JavaSysMon#visitProcessTree}
+ */
+public interface ProcessVisitor {
+    /**
+     * Called on every node. The process tree is traversed depth-first
+     * @param process The current process being visited
+     * @param level How many levels beneath the initial node visited you are (0-indexed)
+     * @return Whether or not to kill the process being visited
+     */
+    boolean visit(OsProcess process, int level);
+}