Google Git
Sign in
eclipse / mat / org.eclipse.mat / refs/heads/master / . / plugins / org.eclipse.mat.ui.help / tasks / analyzingjavacollectionusage.dita
blob: 45b50986bf3d14a70960ba12804af96ad5d76804 [file] [log] [blame]
<?xml version="1.0" encoding="UTF-8"?>
<!--
Copyright (c) 2008, 2021 SAP AG and IBM Corporation.
All rights reserved. This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
SAP AG - initial API and implementation
IBM Corporation - additional collection classes
-->
<!DOCTYPE task PUBLIC "-//OASIS//DTD DITA Task//EN" "task.dtd" >
<task id="task_analyzingjavacollectionusage" xml:lang="en-us">
<title>Analyzing Java Collection Usage</title>
<prolog>
<copyright>
<copyryear year=""></copyryear>
<copyrholder>
Copyright (c) 2008, 2020 SAP AG, IBM Corporation and others.
All rights reserved. This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
</copyrholder>
</copyright>
</prolog>
<taskbody>
<context>
<p>A collection is an object that are used to store, retrieve and
manipulate the data. Memory Analyzer offers the following queries to
analyze java collections:</p>
<table rowsep="1" colsep="1">
<tgroup cols="2">
<tbody>
<row id="arrayfillratio">
<entry>
<b><cmdname>Array Fill Ratio</cmdname> Query</b>
</entry>
<entry>Prints a frequency distribution of fill ratios of
non-primitive arrays. The fill ratio is the proportion of
non-null elements in the array. The arrays are then accumulated
into as many segments as parameterized. Primitive arrays cannot
have null values so this query works only on object arrays.
</entry>
</row>
<row id="arraybysize">
<entry>
<b><cmdname>Arrays Grouped by Size</cmdname> Query</b>
</entry>
<entry>Distribution histogram of given arrays grouped
by the size.</entry>
</row>
<row id="collectionfillratio">
<entry>
<b><cmdname>Collection Fill Ratio</cmdname> Query</b>
</entry>
<entry>
<p>Prints a frequency distribution of fill ratios of given
collections. The following collections can be used for the
query:</p>
<ul>
<li>
<codeblock>java.awt.RenderingHints</codeblock>
</li>
<li>
<codeblock>java.beans.beancontext.BeanContextSupport</codeblock>
</li>
<li>
<codeblock>java.lang.ThreadLocal$ThreadLocalMap</codeblock>
</li>
<li>
<codeblock>java.util.ArrayDeque</codeblock>
</li>
<li>
<codeblock>java.util.ArrayList</codeblock>
</li>
<li>
<codeblock>java.util.Arrays$ArrayList</codeblock>
</li>
<li>
<codeblock>java.util.Collections$CheckedCollection</codeblock>
</li>
<li>
<codeblock>java.util.Collections$CheckedMap</codeblock>
</li>
<li>
<codeblock>java.util.Collections$CheckedSet</codeblock>
</li>
<li>
<codeblock>java.util.Collections$EmptyList</codeblock>
</li>
<li>
<codeblock>java.util.Collections$EmptyMap</codeblock>
</li>
<li>
<codeblock>java.util.Collections$EmptySet</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SetFromMap</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SingletonList</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SingletonSet</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SynchronizedCollection</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SynchronizedSet</codeblock>
</li>
<li>
<codeblock>java.util.Collections$UnmodifiableCollection</codeblock>
</li>
<li>
<codeblock>java.util.Collections$UnmodifiableSet</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ArrayBlockingQueue</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ConcurrentHashMap</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ConcurrentLinkedDeque</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ConcurrentLinkedQueue</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ConcurrentSkipListMap</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.CopyOnWriteArrayList</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.DelayQueue</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.LinkedBlockingDeque</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.LinkedBlockingQueue</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.LinkedTransferQueue</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.SynchronousQueue</codeblock>
</li>
<li>
<codeblock>java.util.EnumMap</codeblock>
</li>
<li>
<codeblock>java.util.EnumSet</codeblock>
</li>
<li>
<codeblock>java.util.HashMap</codeblock>
</li>
<li>
<codeblock>java.util.HashSet</codeblock>
</li>
<li>
<codeblock>java.util.Hashtable</codeblock>
</li>
<li>
<codeblock>java.util.IdentityHashMap</codeblock>
</li>
<li>
<codeblock>java.util.ImmutableCollections$List0</codeblock>
</li>
<li>
<codeblock>java.util.ImmutableCollections$Set1</codeblock>
</li>
<li>
<codeblock>java.util.LinkedHashSet</codeblock>
</li>
<li>
<codeblock>java.util.LinkedList</codeblock>
</li>
<li>
<codeblock>java.util.PriorityQueue</codeblock>
</li>
<li>
<codeblock>java.util.Properties</codeblock>
</li>
<li>
<codeblock>java.util.TreeSet</codeblock>
</li>
<li>
<codeblock>java.util.WeakHashMap</codeblock>
</li>
<li>
<codeblock>java.util.jar.Attributes</codeblock>
</li>
<li>
<codeblock>javax.script.SimpleBindings</codeblock>
</li>
</ul>
<p>One additional custom collection (e.g. non-JDK) collection
can be specified by the 'collection', 'size_attribute' and
'array_attribute' argument.</p>
</entry>
</row>
<row id="collectionsbysize">
<entry>
<b><cmdname>Collections Grouped By Size</cmdname> Query</b>
</entry>
<entry>
<p>Distribution histogram of given collections by
their size. The following collections can be used for the
query. Known collections:</p>
<ul>
<li>
<codeblock>java.awt.RenderingHints</codeblock>
</li>
<li>
<codeblock>java.beans.beancontext.BeanContextSupport</codeblock>
</li>
<li>
<codeblock>java.lang.ThreadLocal$ThreadLocalMap</codeblock>
</li>
<li>
<codeblock>java.util.ArrayDeque</codeblock>
</li>
<li>
<codeblock>java.util.ArrayList</codeblock>
</li>
<li>
<codeblock>java.util.Arrays$ArrayList</codeblock>
</li>
<li>
<codeblock>java.util.Collections$CheckedCollection</codeblock>
</li>
<li>
<codeblock>java.util.Collections$CheckedMap</codeblock>
</li>
<li>
<codeblock>java.util.Collections$CheckedSet</codeblock>
</li>
<li>
<codeblock>java.util.Collections$EmptyList</codeblock>
</li>
<li>
<codeblock>java.util.Collections$EmptyMap</codeblock>
</li>
<li>
<codeblock>java.util.Collections$EmptySet</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SetFromMap</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SingletonList</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SingletonMap</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SingletonSet</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SynchronizedCollection</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SynchronizedMap</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SynchronizedSet</codeblock>
</li>
<li>
<codeblock>java.util.Collections$UnmodifiableCollection</codeblock>
</li>
<li>
<codeblock>java.util.Collections$UnmodifiableMap</codeblock>
</li>
<li>
<codeblock>java.util.Collections$UnmodifiableSet</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ArrayBlockingQueue</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ConcurrentHashMap</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ConcurrentLinkedDeque</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ConcurrentLinkedQueue</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ConcurrentSkipListMap</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ConcurrentSkipListSet</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.CopyOnWriteArrayList</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.CopyOnWriteArraySet</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.DelayQueue</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.LinkedBlockingDeque</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.LinkedBlockingQueue</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.LinkedTransferQueue</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.SynchronousQueue</codeblock>
</li>
<li>
<codeblock>java.util.EnumMap</codeblock>
</li>
<li>
<codeblock>java.util.EnumSet</codeblock>
</li>
<li>
<codeblock>java.util.HashMap</codeblock>
</li>
<li>
<codeblock>java.util.HashSet</codeblock>
</li>
<li>
<codeblock>java.util.Hashtable</codeblock>
</li>
<li>
<codeblock>java.util.IdentityHashMap</codeblock>
</li>
<li>
<codeblock>java.util.ImmutableCollections$List0</codeblock>
</li>
<li>
<codeblock>java.util.ImmutableCollections$List1</codeblock>
</li>
<li>
<codeblock>java.util.ImmutableCollections$List2</codeblock>
</li>
<li>
<codeblock>java.util.ImmutableCollections$ListN</codeblock>
</li>
<li>
<codeblock>java.util.ImmutableCollections$MapN</codeblock>
</li>
<li>
<codeblock>java.util.ImmutableCollections$Set0</codeblock>
</li>
<li>
<codeblock>java.util.ImmutableCollections$Set1</codeblock>
</li>
<li>
<codeblock>java.util.ImmutableCollections$Set2</codeblock>
</li>
<li>
<codeblock>java.util.ImmutableCollections$SetN</codeblock>
</li>
<li>
<codeblock>java.util.jar.Attributes</codeblock>
</li>
<li>
<codeblock>java.util.LinkedHashMap</codeblock>
</li>
<li>
<codeblock>java.util.LinkedHashSet</codeblock>
</li>
<li>
<codeblock>java.util.LinkedList</codeblock>
</li>
<li>
<codeblock>java.util.PriorityQueue</codeblock>
</li>
<li>
<codeblock>java.util.Properties</codeblock>
</li>
<li>
<codeblock>java.util.TreeMap</codeblock>
</li>
<li>
<codeblock>java.util.TreeSet</codeblock>
</li>
<li>
<codeblock>java.util.Vector</codeblock>
</li>
<li>
<codeblock>java.util.WeakHashMap</codeblock>
</li>
<li>
<codeblock>javax.script.SimpleBindings</codeblock>
</li>
<li>
<codeblock>javax.swing.UIDefaults</codeblock>
</li>
</ul>
<p>One additional custom collection (e.g. non-JDK) collection
can be specified by the 'collection', 'size_attribute' and
'array_attribute' argument.</p>
</entry>
</row>
<row>
<entry>
<b><cmdname>Extract List Values</cmdname> Query</b>
</entry>
<entry>
<p>Lists elements of a single LinkedList, ArrayList, Vector,
CopyOnWriteArrayList, PriorityQueue, ArrayDeque
object.</p>
</entry>
</row>
<row>
<entry>
<b><cmdname>Hash Entries</cmdname> Query</b>
</entry>
<entry>
<p>Extracts the key-value pairs from hash maps and
hashtables.</p>
</entry>
</row>
<row>
<entry>
<b><cmdname>Extract Hash Set Values</cmdname> Query</b>
</entry>
<entry>
<p>Lists elements of a single HashSet.</p>
</entry>
</row>
<row id="mapcollision">
<entry>
<b><cmdname>Map Collision Ratio</cmdname> Query</b>
</entry>
<entry>
<p>Prints a frequency distribution of the collision ratios
of map-like collections. The following map-like collections can
be used for the query.</p>
<ul>
<li>
<codeblock>java.util.HashMap</codeblock>
</li>
<li>
<codeblock>java.util.Properties</codeblock>
</li>
<li>
<codeblock>java.util.Hashtable</codeblock>
</li>
<li>
<codeblock>java.util.WeakHashMap</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ConcurrentHashMap$Segment</codeblock>
</li>
<li>
<codeblock>java.util.HashSet</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ConcurrentHashMap</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ConcurrentSkipListMap</codeblock>
</li>
<li>
<codeblock>java.util.concurrent.ConcurrentSkipListSet</codeblock>
</li>
<li>
<codeblock>java.util.Collections$CheckedMap</codeblock>
</li>
<li>
<codeblock>java.util.Collections$CheckedSet</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SynchronizedMap</codeblock>
</li>
<li>
<codeblock>java.util.Collections$SynchronizedSet</codeblock>
</li>
<li>
<codeblock>java.util.Collections$UnmodifiableMap</codeblock>
</li>
<li>
<codeblock>java.util.Collections$UnmodifiableSet</codeblock>
</li>
<li>
<codeblock>java.util.LinkedHashMap</codeblock>
</li>
<li>
<codeblock>java.util.LinkedHashSet</codeblock>
</li>
<li>
<codeblock>java.util.ImmutableCollections$MapN</codeblock>
</li>
<li>
<codeblock>java.util.jar.Attributes</codeblock>
</li>
<li>
<codeblock>java.awt.RenderingHints</codeblock>
</li>
<li>
<codeblock>java.beans.beancontext.BeanContextSupport</codeblock>
</li>
<li>
<codeblock>java.lang.ThreadLocal$ThreadLocalMap</codeblock>
</li>
<li>
<codeblock>javax.script.SimpleBindings</codeblock>
</li>
<li>
<codeblock>javax.swing.UIDefaults</codeblock>
</li>
</ul>
<p> One additional custom map-like (e.g. non-JDK) collection can
be specified by the 'collection', 'size_attribute' and
'array_attribute' argument.</p>
</entry>
</row>
<row id="primitivearrayconstvalue">
<entry>
<b><cmdname>Primitive Arrays with a Constant Value</cmdname> Query</b>
</entry>
<entry>
Lists a summary of all primitive arrays (from a selection) which are filled with one and the
same value.
Arrays with the same length and constant value are grouped together.
</entry>
</row>
</tbody>
</tgroup>
</table>
<p>
All these queries are accessible from the toolbar drop-down menu:
<menucascade>
<uicontrol>Open Query Browser</uicontrol>
<uicontrol>Java Collections</uicontrol>
</menucascade>
</p>
<p>
There are also available from the pop-up context menu using mouse button 2 on a selection of objects from a previous query.
Unsuitable queries for the selection are filtered out and are not shown, so for example a <cmdname>Hash Entries</cmdname> query
would not be offered for a selection of <codeph>ArrayList</codeph> objects.
All the collection queries can be seen from the pop-up context menu using:
<menucascade>
<uicontrol>Search Queries...</uicontrol>
<uicontrol>Java Collections</uicontrol>
</menucascade>
Any query can then be selected and run.
</p>
</context>
</taskbody>
</task>