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/* |
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* Written by members of JCP JSR-166 Expert Group and released to the |
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* public domain. Use, modify, and redistribute this code in any way |
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* without acknowledgement. Other contributors include Andrew Wright, |
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* Jeffrey Hayes, Pat Fischer, Mike Judd. |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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* http://creativecommons.org/licenses/publicdomain |
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* Other contributors include Andrew Wright, Jeffrey Hayes, |
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* Pat Fisher, Mike Judd. |
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*/ |
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import junit.framework.*; |
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public class SystemTest extends JSR166TestCase { |
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public static void main(String[] args) { |
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junit.textui.TestRunner.run(suite()); |
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junit.textui.TestRunner.run(suite()); |
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} |
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public static Test suite() { |
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return new TestSuite(SystemTest.class); |
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return new TestSuite(SystemTest.class); |
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} |
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/** |
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* Nanos between readings of millis is no longer than millis. |
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* Worst case rounding for millisecs; set for 60 cycle millis clock. |
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* This value might need to be changed os JVMs with coarser |
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* System.currentTimeMillis clocks. |
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*/ |
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static final long MILLIS_ROUND = 17; |
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/** |
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* Nanos between readings of millis is no longer than millis (plus |
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* possible rounding). |
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* This shows only that nano timing not (much) worse than milli. |
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*/ |
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public void testNanoTime1() { |
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long m2 = System.currentTimeMillis(); |
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long millis = m2 - m1; |
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long nanos = n2 - n1; |
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assertTrue(nanos >= 0); |
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assertTrue(nanos <= millis * 1000000); |
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long nanosAsMillis = nanos / 1000000; |
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assertTrue(nanosAsMillis <= millis + MILLIS_ROUND); |
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} |
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catch(InterruptedException ie) { |
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fail("unexpected exception"); |
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unexpectedException(); |
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} |
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} |
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/** |
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* Millis between readings of nanos is no longer than nanos |
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* Millis between readings of nanos is less than nanos, adjusting |
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* for rounding. |
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* This shows only that nano timing not (much) worse than milli. |
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*/ |
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public void testNanoTime2() { |
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long n2 = System.nanoTime(); |
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long millis = m2 - m1; |
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long nanos = n2 - n1; |
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assertTrue(nanos >= 0); |
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assertTrue(millis * 1000000 <= nanos); |
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long nanosAsMillis = nanos / 1000000; |
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assertTrue(millis <= nanosAsMillis + MILLIS_ROUND); |
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} |
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catch(InterruptedException ie) { |
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fail("unexpected exception"); |
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unexpectedException(); |
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} |
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} |
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} |
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– |
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