Github user peteryhwong commented on a diff in the pull request:
https://github.com/apache/commons-lang/pull/78#discussion_r29562446
--- Diff: src/main/java/org/apache/commons/lang3/ThreadUtils.java ---
@@ -0,0 +1,459 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.lang3;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * <p>
+ * Helpers for {@code java.lang.Thread} and {@code java.lang.ThreadGroup}.
+ * </p>
+ * <p>
+ * #ThreadSafe#
+ * </p>
+ *
+ * @see java.lang.Thread
+ * @see java.lang.ThreadGroup
+ * @since 3.5
+ * @version $Id$
+ */
+public class ThreadUtils {
+
+ /**
+ * Return the active thread with the specified id if it belong's to
the specified thread group.
+ *
+ * @param threadId The thread id
+ * @param threadGroup The thread group
+ * @return The thread which belongs to a specified thread group and
the thread's id match the specified id.
+ * {@code null} is returned if no such thread exists
+ * @throws IllegalArgumentException if the specified id is zero or
negative or the group is null
+ * @throws SecurityException
+ * if the current thread cannot access the system thread group
+ *
+ * @throws SecurityException if the current thread cannot modify
+ * thread groups from this thread's thread group up to the
system thread group
+ */
+ public static Thread findThreadById(final long threadId, final
ThreadGroup threadGroup) {
+ if (threadGroup == null) {
+ throw new IllegalArgumentException("The thread group must not
be null");
+ }
+ final Thread thread = findThreadById(threadId);
+ if(thread != null && threadGroup.equals(thread.getThreadGroup())) {
+ return thread;
+ }
+ return null;
+ }
+
+ /**
+ * Return the active thread with the specified id if it belong's to a
thread group with the specified group name.
+ *
+ * @param threadId The thread id
+ * @param threadGroupName The thread group name
+ * @return The threads which belongs to a thread group with the
specified group name and the thread's id match the specified id.
+ * {@code null} is returned if no such thread exists
+ * @throws IllegalArgumentException if the specified id is zero or
negative or the group name is null
+ * @throws SecurityException
+ * if the current thread cannot access the system thread group
+ *
+ * @throws SecurityException if the current thread cannot modify
+ * thread groups from this thread's thread group up to the
system thread group
+ */
+ public static Thread findThreadById(final long threadId, final String
threadGroupName) {
+ if (threadGroupName == null) {
+ throw new IllegalArgumentException("The thread group name must
not be null");
+ }
+ final Thread thread = findThreadById(threadId);
+ if(thread != null && thread.getThreadGroup() != null &&
thread.getThreadGroup().getName().equals(threadGroupName)) {
+ return thread;
+ }
+ return null;
+ }
+
+ /**
+ * Return active threads with the specified name if they belong to a
specified thread group.
+ *
+ * @param threadName The thread name
+ * @param threadGroupName The thread group
+ * @return The threads which belongs to a thread group and the
thread's name match the specified name,
+ * An empty collection is returned if no such thread exists. The
collection returned is always unmodifiable.
+ * @throws IllegalArgumentException if the specified thread name or
group is null
+ * @throws SecurityException
+ * if the current thread cannot access the system thread group
+ *
+ * @throws SecurityException if the current thread cannot modify
+ * thread groups from this thread's thread group up to the
system thread group
+ */
+ public static Collection<Thread> findThreadsByName(final String
threadName, final ThreadGroup threadGroup) {
+ return findThreads(threadGroup, false, new
NamePredicate(threadName));
+ }
+
+ /**
+ * Return active threads with the specified name if they belong to a
thread group with the specified group name.
+ *
+ * @param threadName The thread name
+ * @param threadGroupName The thread group name
+ * @return The threads which belongs to a thread group with the
specified group name and the thread's name match the specified name,
+ * An empty collection is returned if no such thread exists. The
collection returned is always unmodifiable.
+ * @throws IllegalArgumentException if the specified thread name or
group name is null
+ * @throws SecurityException
+ * if the current thread cannot access the system thread group
+ *
+ * @throws SecurityException if the current thread cannot modify
+ * thread groups from this thread's thread group up to the
system thread group
+ */
+ public static Collection<Thread> findThreadsByName(final String
threadName, final String threadGroupName) {
+ if (threadName == null) {
+ throw new IllegalArgumentException("The thread name must not
be null");
+ }
+ if (threadGroupName == null) {
+ throw new IllegalArgumentException("The thread group name must
not be null");
+ }
+
+ final Collection<Thread> result = new ArrayList<Thread>();
+ for(final ThreadGroup group : findThreadGroups(new
NamePredicate(threadGroupName))) {
+ result.addAll(findThreads(group, false, new
NamePredicate(threadName)));
--- End diff --
The NamePredicate object is the same in every iteration. Hence only one
instance is required outside of the for loop.
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