Package org.jvnet.hudson.test
Class MemoryAssert
- java.lang.Object
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- org.jvnet.hudson.test.MemoryAssert
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public class MemoryAssert extends Object
Static utility methods for verifying heap memory usage. Uses the INSANE library to traverse the heap from within your test.Object sizes are in an idealized JVM in which pointers are 4 bytes (realistic even for modern 64-bit JVMs in which
-XX:+UseCompressedOops
is the default) but objects are aligned on 8-byte boundaries (so dropping anint
field does not always save memory).import static org.jvnet.hudson.test.MemoryAssert.*;
to use.
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
MemoryAssert.HistogramElement
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Method Summary
All Methods Static Methods Concrete Methods Deprecated Methods Modifier and Type Method Description static void
assertGC(WeakReference<?> reference)
Deprecated.static void
assertGC(WeakReference<?> reference, boolean allowSoft)
Forces GC by causing an OOM and then verifies the givenWeakReference
has been garbage collected.static void
assertHeapUsage(Object o, int max)
Verifies that an object and its transitive reference graph occupy at most a predetermined amount of memory.static List<MemoryAssert.HistogramElement>
increasedMemory(Callable<Void> callable, org.netbeans.insane.scanner.Filter... filters)
Counts how much more memory is held in Jenkins by doing some operation.
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Method Detail
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assertHeapUsage
public static void assertHeapUsage(Object o, int max) throws Exception
Verifies that an object and its transitive reference graph occupy at most a predetermined amount of memory. The referents ofWeakReference
and the like are ignored.To use, run your test for the first time with
max
of0
; when it fails, use the reported actual size as your assertion maximum. When improving memory usage, run again with0
and tighten the test to both demonstrate your improvement quantitatively and prevent regressions.- Parameters:
o
- the object to measuremax
- the maximum desired memory usage (in bytes)- Throws:
Exception
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increasedMemory
public static List<MemoryAssert.HistogramElement> increasedMemory(Callable<Void> callable, org.netbeans.insane.scanner.Filter... filters) throws Exception
Counts how much more memory is held in Jenkins by doing some operation.- Parameters:
callable
- an actionfilters
- things to exclude- Returns:
- a histogram of the heap delta after running the operation
- Throws:
Exception
- Since:
- 1.500
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assertGC
@Deprecated public static void assertGC(WeakReference<?> reference)
Deprecated.
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assertGC
public static void assertGC(WeakReference<?> reference, boolean allowSoft)
Forces GC by causing an OOM and then verifies the givenWeakReference
has been garbage collected.- Parameters:
reference
- object used to verify garbage collection.allowSoft
- if true, pass even ifSoftReference
s apparently needed to be cleared by forcing anOutOfMemoryError
; if false, fail in such a case (though the failure will be slow)
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