mirror of
https://github.com/github/codeql.git
synced 2026-04-14 19:44:03 +02:00
e21cbe82a9
Where possible update Java documentation links to Java 11. Additionally update some other links to use HTTPS.
53 lines
1.6 KiB
XML
53 lines
1.6 KiB
XML
<!DOCTYPE qhelp PUBLIC
|
|
"-//Semmle//qhelp//EN"
|
|
"qhelp.dtd">
|
|
<qhelp>
|
|
|
|
|
|
<overview>
|
|
<p>A class that overrides <code>compareTo</code> but not <code>equals</code>
|
|
may not implement a natural ordering that is consistent with <code>equals</code>.
|
|
</p>
|
|
|
|
</overview>
|
|
<recommendation>
|
|
|
|
<p>Although this consistency is not strictly required by the <code>compareTo</code> contract,
|
|
usually both methods should be overridden to ensure that they are consistent, that is, that
|
|
<code>x.compareTo(y)==0</code> is <code>true</code> if and only if <code>x.equals(y)</code>
|
|
is <code>true</code>, for any non-null <code>x</code> and <code>y</code>.</p>
|
|
|
|
</recommendation>
|
|
<example>
|
|
|
|
<p>In the following example, the class <code>InconsistentCompareTo</code> overrides
|
|
<code>compareTo</code> but not <code>equals</code>.</p>
|
|
|
|
<sample src="InconsistentCompareTo.java" />
|
|
|
|
<p>In the following example, the class <code>InconsistentCompareToFix</code> overrides both
|
|
<code>compareTo</code> and <code>equals</code>.</p>
|
|
|
|
<sample src="InconsistentCompareToGood.java" />
|
|
|
|
<p>
|
|
If you require a natural ordering that is inconsistent with <code>equals</code>, you should document it clearly.
|
|
</p>
|
|
|
|
</example>
|
|
<references>
|
|
|
|
|
|
<li>
|
|
J. Bloch, <em>Effective Java (second edition)</em>, Item 12. Addison-Wesley, 2008.
|
|
</li>
|
|
<li>
|
|
Java API Specification:
|
|
<a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/Comparable.html#compareTo(T)">Comparable.compareTo</a>,
|
|
<a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/Object.html#equals(java.lang.Object)">Object.equals</a>.
|
|
</li>
|
|
|
|
|
|
</references>
|
|
</qhelp>
|