ViewVC Help

View File | Revision Log | Show Annotations | Download File | Root Listing

root/jsr166/jsr166/src/jsr166y/ForkJoinTask.java

Comparing jsr166/src/jsr166y/ForkJoinTask.java (file contents):
Revision 1.13 by dl, Wed Jul 22 19:04:11 2009 UTC vs.
Revision 1.22 by jsr166, Sun Jul 26 17:33:37 2009 UTC

#	Line 5 | Line 5
5		*/
6
7		package jsr166y;
8	<	import java.io.Serializable;
9	<	import java.util.*;
8	>
9		import java.util.concurrent.*;
10	<	import java.util.concurrent.atomic.*;
11	<	import sun.misc.Unsafe;
12	<	import java.lang.reflect.*;
10	>
11	>	import java.io.Serializable;
12	>	import java.util.Collection;
13	>	import java.util.Collections;
14	>	import java.util.List;
15	>	import java.util.Map;
16	>	import java.util.WeakHashMap;
17
18		/**
19		* Abstract base class for tasks that run within a {@link
#	Line 83 | Line 86 | import java.lang.reflect.*;
86		* methods), some of them may only be called from within other
87		* ForkJoinTasks (as may be determined using method {@link
88		* #inForkJoinPool}).  Attempts to invoke them in other contexts
89	<	* result in exceptions or errors possibly including
89	>	* result in exceptions or errors, possibly including
90		* ClassCastException.
91		*
92		* <p>Most base support methods are {@code final} because their
#	Line 162 | Line 165 | public abstract class ForkJoinTask<V> im
165		*/
166		static ForkJoinWorkerThread getWorker() {
167		Thread t = Thread.currentThread();
168	<	return ((t instanceof ForkJoinWorkerThread)?
169	<	(ForkJoinWorkerThread)t : null);
168	>	return ((t instanceof ForkJoinWorkerThread) ?
169	>	(ForkJoinWorkerThread) t : null);
170		}
171
172		final boolean casStatus(int cmp, int val) {
#	Line 189 | Line 192 | public abstract class ForkJoinTask<V> im
192		ForkJoinPool pool = getPool();
193		if (pool != null) {
194		int s; // Clear signal bits while setting completion status
195	<	do;while ((s = status) >= 0 && !casStatus(s, completion));
195	>	do {} while ((s = status) >= 0 && !casStatus(s, completion));
196
197		if ((s & SIGNAL_MASK) != 0) {
198		if ((s &= INTERNAL_SIGNAL_MASK) != 0)
199		pool.updateRunningCount(s);
200	<	synchronized(this) { notifyAll(); }
200	>	synchronized (this) { notifyAll(); }
201		}
202		}
203		else
#	Line 207 | Line 210 | public abstract class ForkJoinTask<V> im
210		*/
211		private void externallySetCompletion(int completion) {
212		int s;
213	<	do;while ((s = status) >= 0 &&
214	<	!casStatus(s, (s & SIGNAL_MASK) | completion));
215	<	synchronized(this) { notifyAll(); }
213	>	do {} while ((s = status) >= 0 &&
214	>	!casStatus(s, (s & SIGNAL_MASK) | completion));
215	>	synchronized (this) { notifyAll(); }
216		}
217
218		/**
219	<	* Sets status to indicate normal completion
219	>	* Sets status to indicate normal completion.
220		*/
221		final void setNormalCompletion() {
222		// Try typical fast case -- single CAS, no signal, not already done.
#	Line 225 | Line 228 | public abstract class ForkJoinTask<V> im
228		// internal waiting and notification
229
230		/**
231	<	* Performs the actual monitor wait for awaitDone
231	>	* Performs the actual monitor wait for awaitDone.
232		*/
233		private void doAwaitDone() {
234		// Minimize lock bias and in/de-flation effects by maximizing
235		// chances of waiting inside sync
236		try {
237		while (status >= 0)
238	<	synchronized(this) { if (status >= 0) wait(); }
238	>	synchronized (this) { if (status >= 0) wait(); }
239		} catch (InterruptedException ie) {
240		onInterruptedWait();
241		}
242		}
243
244		/**
245	<	* Performs the actual monitor wait for awaitDone
245	>	* Performs the actual timed monitor wait for awaitDone.
246		*/
247		private void doAwaitDone(long startTime, long nanos) {
248	<	synchronized(this) {
248	>	synchronized (this) {
249		try {
250		while (status >= 0) {
251		long nt = nanos - System.nanoTime() - startTime;
252		if (nt <= 0)
253		break;
254	<	wait(nt / 1000000, (int)(nt % 1000000));
254	>	wait(nt / 1000000, (int) (nt % 1000000));
255		}
256		} catch (InterruptedException ie) {
257		onInterruptedWait();
#	Line 264 | Line 267 | public abstract class ForkJoinTask<V> im
267		*
268		* @return status upon exit
269		*/
270	<	private int awaitDone(ForkJoinWorkerThread w, boolean maintainParallelism) {
271	<	ForkJoinPool pool = w == null? null : w.pool;
270	>	private int awaitDone(ForkJoinWorkerThread w,
271	>	boolean maintainParallelism) {
272	>	ForkJoinPool pool = (w == null) ? null : w.pool;
273		int s;
274		while ((s = status) >= 0) {
275	<	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
275	>	if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) {
276		if (pool == null || !pool.preJoin(this, maintainParallelism))
277		doAwaitDone();
278		if (((s = status) & INTERNAL_SIGNAL_MASK) != 0)
#	Line 281 | Line 285 | public abstract class ForkJoinTask<V> im
285
286		/**
287		* Timed version of awaitDone
288	+	*
289		* @return status upon exit
290		*/
291		private int awaitDone(ForkJoinWorkerThread w, long nanos) {
292	<	ForkJoinPool pool = w == null? null : w.pool;
292	>	ForkJoinPool pool = (w == null) ? null : w.pool;
293		int s;
294		while ((s = status) >= 0) {
295	<	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
295	>	if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) {
296		long startTime = System.nanoTime();
297		if (pool == null || !pool.preJoin(this, false))
298		doAwaitDone(startTime, nanos);
#	Line 309 | Line 314 | public abstract class ForkJoinTask<V> im
314		*/
315		private void adjustPoolCountsOnUnblock(ForkJoinPool pool) {
316		int s;
317	<	do;while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK));
317	>	do {} while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK));
318		if (pool != null && (s &= INTERNAL_SIGNAL_MASK) != 0)
319		pool.updateRunningCount(s);
320		}
#	Line 364 | Line 369 | public abstract class ForkJoinTask<V> im
369
370		/**
371		* Returns result or throws exception using j.u.c.Future conventions.
372	<	* Only call when isDone known to be true.
372	>	* Only call when {@code isDone} known to be true.
373		*/
374		private V reportFutureResult()
375		throws ExecutionException, InterruptedException {
#	Line 430 | Line 435 | public abstract class ForkJoinTask<V> im
435		try {
436		if (!exec())
437		return;
438	<	} catch(Throwable rex) {
438	>	} catch (Throwable rex) {
439		setDoneExceptionally(rex);
440		return;
441		}
#	Line 462 | Line 467 | public abstract class ForkJoinTask<V> im
467		final void cancelIgnoringExceptions() {
468		try {
469		cancel(false);
470	<	} catch(Throwable ignore) {
470	>	} catch (Throwable ignore) {
471		}
472		}
473
#	Line 474 | Line 479 | public abstract class ForkJoinTask<V> im
479		ForkJoinTask<?> t;
480		while ((s = status) >= 0 && (t = w.scanWhileJoining(this)) != null)
481		t.quietlyExec();
482	<	return (s >= 0)? awaitDone(w, false) : s; // block if no work
482	>	return (s >= 0) ? awaitDone(w, false) : s; // block if no work
483		}
484
485		// public methods
#	Line 486 | Line 491 | public abstract class ForkJoinTask<V> im
491		* method may be invoked only from within ForkJoinTask
492		* computations (as may be determined using method {@link
493		* #inForkJoinPool}). Attempts to invoke in other contexts result
494	<	* in exceptions or errors possibly including ClassCastException.
494	>	* in exceptions or errors, possibly including ClassCastException.
495	>	*
496	>	* @return {@code this}, to simplify usage.
497		*/
498	<	public final void fork() {
499	<	((ForkJoinWorkerThread)(Thread.currentThread())).pushTask(this);
498	>	public final ForkJoinTask<V> fork() {
499	>	((ForkJoinWorkerThread) Thread.currentThread())
500	>	.pushTask(this);
501	>	return this;
502		}
503
504		/**
#	Line 527 | Line 536 | public abstract class ForkJoinTask<V> im
536		* both of them or an exception is encountered. This method may be
537		* invoked only from within ForkJoinTask computations (as may be
538		* determined using method {@link #inForkJoinPool}). Attempts to
539	<	* invoke in other contexts result in exceptions or errors
539	>	* invoke in other contexts result in exceptions or errors,
540		* possibly including ClassCastException.
541		*
542		* @param t1 one task
#	Line 547 | Line 556 | public abstract class ForkJoinTask<V> im
556		* may be cancelled.  This method may be invoked only from within
557		* ForkJoinTask computations (as may be determined using method
558		* {@link #inForkJoinPool}). Attempts to invoke in other contexts
559	<	* result in exceptions or errors possibly including
559	>	* result in exceptions or errors, possibly including
560		* ClassCastException.
561	+	*
562		* @param tasks the array of tasks
563		* @throws NullPointerException if tasks or any element are null
564		* @throws RuntimeException or Error if any task did so
#	Line 592 | Line 602 | public abstract class ForkJoinTask<V> im
602		* encounters an exception, others may be cancelled.  This method
603		* may be invoked only from within ForkJoinTask computations (as
604		* may be determined using method {@link
605	<	* #inForkJoinPool}). Attempts to invoke in other contexts resul!t
606	<	* in exceptions or errors possibly including ClassCastException.
605	>	* #inForkJoinPool}). Attempts to invoke in other contexts result
606	>	* in exceptions or errors, possibly including ClassCastException.
607		*
608		* @param tasks the collection of tasks
609	+	* @return the tasks argument, to simplify usage
610		* @throws NullPointerException if tasks or any element are null
611		* @throws RuntimeException or Error if any task did so
612		*/
613	<	public static void invokeAll(Collection<? extends ForkJoinTask<?>> tasks) {
614	<	if (!(tasks instanceof List)) {
615	<	invokeAll(tasks.toArray(new ForkJoinTask[tasks.size()]));
616	<	return;
613	>	public static <T extends ForkJoinTask<?>> Collection<T> invokeAll(Collection<T> tasks) {
614	>	if (!(tasks instanceof List<?>)) {
615	>	invokeAll(tasks.toArray(new ForkJoinTask<?>[tasks.size()]));
616	>	return tasks;
617		}
618	+	@SuppressWarnings("unchecked")
619		List<? extends ForkJoinTask<?>> ts =
620	<	(List<? extends ForkJoinTask<?>>)tasks;
620	>	(List<? extends ForkJoinTask<?>>) tasks;
621		Throwable ex = null;
622		int last = ts.size() - 1;
623		for (int i = last; i >= 0; --i) {
#	Line 636 | Line 648 | public abstract class ForkJoinTask<V> im
648		}
649		if (ex != null)
650		rethrowException(ex);
651	+	return tasks;
652		}
653
654		/**
#	Line 680 | Line 693 | public abstract class ForkJoinTask<V> im
693		*
694		* @param mayInterruptIfRunning this value is ignored in the
695		* default implementation because tasks are not in general
696	<	* cancelled via interruption.
696	>	* cancelled via interruption
697		*
698		* @return true if this task is now cancelled
699		*/
#	Line 730 | Line 743 | public abstract class ForkJoinTask<V> im
743		*/
744		public void completeExceptionally(Throwable ex) {
745		setDoneExceptionally((ex instanceof RuntimeException) ||
746	<	(ex instanceof Error)? ex :
746	>	(ex instanceof Error) ? ex :
747		new RuntimeException(ex));
748		}
749
#	Line 749 | Line 762 | public abstract class ForkJoinTask<V> im
762		public void complete(V value) {
763		try {
764		setRawResult(value);
765	<	} catch(Throwable rex) {
765	>	} catch (Throwable rex) {
766		setDoneExceptionally(rex);
767		return;
768		}
#	Line 781 | Line 794 | public abstract class ForkJoinTask<V> im
794		* tasks). This method may be invoked only from within
795		* ForkJoinTask computations (as may be determined using method
796		* {@link #inForkJoinPool}). Attempts to invoke in other contexts
797	<	* resul!t in exceptions or errors possibly including
797	>	* result in exceptions or errors, possibly including
798		* ClassCastException.
799		*
800		* @return the computed result
801		*/
802		public final V helpJoin() {
803	<	ForkJoinWorkerThread w = (ForkJoinWorkerThread)(Thread.currentThread());
803	>	ForkJoinWorkerThread w = (ForkJoinWorkerThread) Thread.currentThread();
804		if (status < 0 || !w.unpushTask(this) || !tryExec())
805		reportException(busyJoin(w));
806		return getRawResult();
#	Line 797 | Line 810 | public abstract class ForkJoinTask<V> im
810		* Possibly executes other tasks until this task is ready.  This
811		* method may be invoked only from within ForkJoinTask
812		* computations (as may be determined using method {@link
813	<	* #inForkJoinPool}). Attempts to invoke in other contexts resul!t
814	<	* in exceptions or errors possibly including ClassCastException.
813	>	* #inForkJoinPool}). Attempts to invoke in other contexts result
814	>	* in exceptions or errors, possibly including ClassCastException.
815		*/
816		public final void quietlyHelpJoin() {
817		if (status >= 0) {
818		ForkJoinWorkerThread w =
819	<	(ForkJoinWorkerThread)(Thread.currentThread());
819	>	(ForkJoinWorkerThread) Thread.currentThread();
820		if (!w.unpushTask(this) || !tryQuietlyInvoke())
821		busyJoin(w);
822		}
#	Line 842 | Line 855 | public abstract class ForkJoinTask<V> im
855		* joined, instead executing them until all are processed.
856		*/
857		public static void helpQuiesce() {
858	<	((ForkJoinWorkerThread)(Thread.currentThread())).
859	<	helpQuiescePool();
858	>	((ForkJoinWorkerThread) Thread.currentThread())
859	>	.helpQuiescePool();
860		}
861
862		/**
#	Line 866 | Line 879 | public abstract class ForkJoinTask<V> im
879		* Returns the pool hosting the current task execution, or null
880		* if this task is executing outside of any ForkJoinPool.
881		*
882	<	* @return the pool, or null if none.
882	>	* @return the pool, or null if none
883		*/
884		public static ForkJoinPool getPool() {
885		Thread t = Thread.currentThread();
886	<	return ((t instanceof ForkJoinWorkerThread)?
887	<	((ForkJoinWorkerThread)t).pool : null);
886	>	return (t instanceof ForkJoinWorkerThread) ?
887	>	((ForkJoinWorkerThread) t).pool : null;
888		}
889
890		/**
891	<	* Returns true if the current thread is executing as a
891	>	* Returns {@code true} if the current thread is executing as a
892		* ForkJoinPool computation.
893	<	* @return <code>true</code> if the current thread is executing as a
893	>	*
894	>	* @return {@code true} if the current thread is executing as a
895		* ForkJoinPool computation, or false otherwise
896		*/
897		public static boolean inForkJoinPool() {
#	Line 893 | Line 907 | public abstract class ForkJoinTask<V> im
907		* were not, stolen. This method may be invoked only from within
908		* ForkJoinTask computations (as may be determined using method
909		* {@link #inForkJoinPool}). Attempts to invoke in other contexts
910	<	* result in exceptions or errors possibly including
910	>	* result in exceptions or errors, possibly including
911		* ClassCastException.
912		*
913		* @return true if unforked
914		*/
915		public boolean tryUnfork() {
916	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).unpushTask(this);
916	>	return ((ForkJoinWorkerThread) Thread.currentThread())
917	>	.unpushTask(this);
918		}
919
920		/**
#	Line 911 | Line 926 | public abstract class ForkJoinTask<V> im
926		* @return the number of tasks
927		*/
928		public static int getQueuedTaskCount() {
929	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).
930	<	getQueueSize();
929	>	return ((ForkJoinWorkerThread) Thread.currentThread())
930	>	.getQueueSize();
931		}
932
933		/**
#	Line 928 | Line 943 | public abstract class ForkJoinTask<V> im
943		* @return the surplus number of tasks, which may be negative
944		*/
945		public static int getSurplusQueuedTaskCount() {
946	<	return ((ForkJoinWorkerThread)(Thread.currentThread()))
946	>	return ((ForkJoinWorkerThread) Thread.currentThread())
947		.getEstimatedSurplusTaskCount();
948		}
949
#	Line 977 | Line 992 | public abstract class ForkJoinTask<V> im
992		* This method may be invoked only from within ForkJoinTask
993		* computations (as may be determined using method {@link
994		* #inForkJoinPool}). Attempts to invoke in other contexts result
995	<	* in exceptions or errors possibly including ClassCastException.
995	>	* in exceptions or errors, possibly including ClassCastException.
996		*
997		* @return the next task, or null if none are available
998		*/
999		protected static ForkJoinTask<?> peekNextLocalTask() {
1000	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).peekTask();
1000	>	return ((ForkJoinWorkerThread) Thread.currentThread())
1001	>	.peekTask();
1002		}
1003
1004		/**
#	Line 992 | Line 1008 | public abstract class ForkJoinTask<V> im
1008		* be useful otherwise.  This method may be invoked only from
1009		* within ForkJoinTask computations (as may be determined using
1010		* method {@link #inForkJoinPool}). Attempts to invoke in other
1011	<	* contexts result in exceptions or errors possibly including
1011	>	* contexts result in exceptions or errors, possibly including
1012		* ClassCastException.
1013		*
1014		* @return the next task, or null if none are available
1015		*/
1016		protected static ForkJoinTask<?> pollNextLocalTask() {
1017	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).pollLocalTask();
1017	>	return ((ForkJoinWorkerThread) Thread.currentThread())
1018	>	.pollLocalTask();
1019		}
1020
1021		/**
#	Line 1012 | Line 1029 | public abstract class ForkJoinTask<V> im
1029		* otherwise.  This method may be invoked only from within
1030		* ForkJoinTask computations (as may be determined using method
1031		* {@link #inForkJoinPool}). Attempts to invoke in other contexts
1032	<	* result in exceptions or errors possibly including
1032	>	* result in exceptions or errors, possibly including
1033		* ClassCastException.
1034		*
1035		* @return a task, or null if none are available
1036		*/
1037		protected static ForkJoinTask<?> pollTask() {
1038	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).
1039	<	pollTask();
1038	>	return ((ForkJoinWorkerThread) Thread.currentThread())
1039	>	.pollTask();
1040	>	}
1041	>
1042	>	// adaptors
1043	>
1044	>	/**
1045	>	* Returns a new ForkJoinTask that performs the {@code run}
1046	>	* method of the given Runnable as its action, and returns a null
1047	>	* result upon {@code join}.
1048	>	*
1049	>	* @param runnable the runnable action
1050	>	* @return the task
1051	>	*/
1052	>	public static ForkJoinTask<Void> adapt(Runnable runnable) {
1053	>	return new ForkJoinPool.AdaptedRunnable<Void>(runnable, null);
1054	>	}
1055	>
1056	>	/**
1057	>	* Returns a new ForkJoinTask that performs the {@code run}
1058	>	* method of the given Runnable as its action, and returns the
1059	>	* given result upon {@code join}.
1060	>	*
1061	>	* @param runnable the runnable action
1062	>	* @param result the result upon completion
1063	>	* @return the task
1064	>	*/
1065	>	public static <T> ForkJoinTask<T> adapt(Runnable runnable, T result) {
1066	>	return new ForkJoinPool.AdaptedRunnable<T>(runnable, result);
1067	>	}
1068	>
1069	>	/**
1070	>	* Returns a new ForkJoinTask that performs the {@code call}
1071	>	* method of the given Callable as its action, and returns its
1072	>	* result upon {@code join}, translating any checked
1073	>	* exceptions encountered into {@code RuntimeException}.
1074	>	*
1075	>	* @param callable the callable action
1076	>	* @return the task
1077	>	*/
1078	>	public static <T> ForkJoinTask<T> adapt(Callable<T> callable) {
1079	>	return new ForkJoinPool.AdaptedCallable<T>(callable);
1080		}
1081
1082		// Serialization support
#	Line 1051 | Line 1108 | public abstract class ForkJoinTask<V> im
1108		status |= EXTERNAL_SIGNAL; // conservatively set external signal
1109		Object ex = s.readObject();
1110		if (ex != null)
1111	<	setDoneExceptionally((Throwable)ex);
1111	>	setDoneExceptionally((Throwable) ex);
1112		}
1113
1114	<	// Temporary Unsafe mechanics for preliminary release
1115	<	private static Unsafe getUnsafe() throws Throwable {
1114	>	// Unsafe mechanics
1115	>
1116	>	private static final sun.misc.Unsafe UNSAFE = getUnsafe();
1117	>	private static final long statusOffset =
1118	>	objectFieldOffset("status", ForkJoinTask.class);
1119	>
1120	>	private static long objectFieldOffset(String field, Class<?> klazz) {
1121		try {
1122	<	return Unsafe.getUnsafe();
1122	>	return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));
1123	>	} catch (NoSuchFieldException e) {
1124	>	// Convert Exception to corresponding Error
1125	>	NoSuchFieldError error = new NoSuchFieldError(field);
1126	>	error.initCause(e);
1127	>	throw error;
1128	>	}
1129	>	}
1130	>
1131	>	/**
1132	>	* Returns a sun.misc.Unsafe.  Suitable for use in a 3rd party package.
1133	>	* Replace with a simple call to Unsafe.getUnsafe when integrating
1134	>	* into a jdk.
1135	>	*
1136	>	* @return a sun.misc.Unsafe
1137	>	*/
1138	>	private static sun.misc.Unsafe getUnsafe() {
1139	>	try {
1140	>	return sun.misc.Unsafe.getUnsafe();
1141		} catch (SecurityException se) {
1142		try {
1143		return java.security.AccessController.doPrivileged
1144	<	(new java.security.PrivilegedExceptionAction<Unsafe>() {
1145	<	public Unsafe run() throws Exception {
1146	<	return getUnsafePrivileged();
1144	>	(new java.security
1145	>	.PrivilegedExceptionAction<sun.misc.Unsafe>() {
1146	>	public sun.misc.Unsafe run() throws Exception {
1147	>	java.lang.reflect.Field f = sun.misc
1148	>	.Unsafe.class.getDeclaredField("theUnsafe");
1149	>	f.setAccessible(true);
1150	>	return (sun.misc.Unsafe) f.get(null);
1151		}});
1152		} catch (java.security.PrivilegedActionException e) {
1153	<	throw e.getCause();
1153	>	throw new RuntimeException("Could not initialize intrinsics",
1154	>	e.getCause());
1155		}
1156		}
1157		}
1073	–
1074	–	private static Unsafe getUnsafePrivileged()
1075	–	throws NoSuchFieldException, IllegalAccessException {
1076	–	Field f = Unsafe.class.getDeclaredField("theUnsafe");
1077	–	f.setAccessible(true);
1078	–	return (Unsafe) f.get(null);
1079	–	}
1080	–
1081	–	private static long fieldOffset(String fieldName)
1082	–	throws NoSuchFieldException {
1083	–	return UNSAFE.objectFieldOffset
1084	–	(ForkJoinTask.class.getDeclaredField(fieldName));
1085	–	}
1086	–
1087	–	static final Unsafe UNSAFE;
1088	–	static final long statusOffset;
1089	–
1090	–	static {
1091	–	try {
1092	–	UNSAFE = getUnsafe();
1093	–	statusOffset = fieldOffset("status");
1094	–	} catch (Throwable e) {
1095	–	throw new RuntimeException("Could not initialize intrinsics", e);
1096	–	}
1097	–	}
1098	–
1158		}

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines