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SPR-7470 

+ add basic documentation for c: namespace

git-svn-id: https://src.springframework.org/svn/spring-framework/trunk@3814 50f2f4bb-b051-0410-bef5-90022cba6387
This commit is contained in:
Costin Leau 2010-12-15 16:12:54 +00:00
parent 0e94956e1e
commit 1feb389e27
1 changed files with 47 additions and 0 deletions
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47
spring-framework-reference/src/beans-dependencies.xml
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@ -1030,6 +1030,53 @@ support=support@example.co.uk</programlisting>
</note>
</section>
<section id="beans-c-namespace">
<title>XML shortcut with the c-namespace</title>
<para>Similar to the <xref linkend="beans-p-namespace"/>, the <emphasis>c-namespace</emphasis>, newly introduced in Spring 3.1,
allows usage of inlined attributes for configuring the constructor arguments rather then nested <literal>constructor-arg</literal>
elements.</para>
<para>Let's review the examples from <xref linkend="beans-constructor-injection"/> with the <literal>c</literal> namespace:</para>
<programlisting language="java">&lt;beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/c"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd"&gt;
&lt;bean id="bar" class="x.y.Bar"/&gt;
&lt;bean id="baz" class="x.y.Baz"/&gt;
&lt;-- 'traditional' declaration --&gt;
&lt;bean id="foo" class="x.y.Foo"&gt;
&lt;constructor-arg ref="bar"/&gt;
&lt;constructor-arg ref="baz"/&gt;
&lt;constructor-arg value="foo@bar.com"/&gt;
&lt;/bean&gt;
&lt;-- 'c-namespace' declaration --&gt;
&lt;bean id="foo" class="x.y.Foo" c:bar-ref="bar" c:baz-ref="baz" c:email="foo@bar.com"&gt;
&lt;/beans&gt;</programlisting>
<para>The <literal>c</literal> namespace uses the same conventions as the <literal>p</literal> one (trailing <literal>-ref</literal> for bean references)
for setting the constructor arguments by their names. And just as well, it needs to be declared even though it is not defined in an XSD schema
(but it exists inside the Spring core).</para>
<para>For the rare cases where the constructor argument names are not available (usually if the bytecode was compiled without debugging information), one can
use fallback to the argument indexes:</para>
<programlisting language="java">&lt;-- 'c-namespace' index declaration --&gt;
&lt;bean id="foo" class="x.y.Foo" c:_0-ref="bar" c:_1-ref="baz"&gt;</programlisting>
<note>Due to the XML grammar, the index notation requires the presence of the leading <emphasis>_</emphasis> as XML attribute names cannot start
with a number (even though some IDE allow it).</note>
<para>In practice, the constructor resolution <link linkend="beans-factory-ctor-arguments-resolution">mechanism</link> is quite efficient in matching arguments so
unless one really needs to, we recommend using the name notation through-out your configuration.</para>
</section>
<section id="beans-compound-property-names">
<title>Compound property names</title>