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Improved overview doc comparing traditional and new approach.

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This commit is contained in:
Ulrik Sandberg
2007-04-09 18:20:26 +00:00
parent 8611ea7571
commit 2746ce6d94
1 changed files with 59 additions and 42 deletions
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101
spring-ldap/docs/reference/src/overview.xml
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@@ -31,7 +31,8 @@
want, adding it to a list.</para>
<para>The traditional way of implementing this person name search method
in Java LDAP looks like this:</para>
in Java LDAP looks like this, where the code marked as bold actually
performs tasks related to the business purpose of the method:</para>
<informalexample>
<programlisting>package com.example.dao;
@@ -54,14 +55,14 @@ public class TraditionalPersonDaoImpl implements PersonDao {
try {
SearchControls controls = new SearchControls();
controls.setSearchScope(SearchControls.SUBTREE_SCOPE);
results = ctx.search("", "(objectclass=person)", controls);
results = ctx.<emphasis role="bold">search("", "(objectclass=person)"</emphasis>, controls);
while (results.hasMore()) {
SearchResult searchResult = (SearchResult) results.next();
Attributes attributes = searchResult.getAttributes();
Attribute attr = attributes.get("cn");
<emphasis role="bold">Attribute attr = attributes.get("cn");
String cn = (String) attr.get();
list.add(cn);
list.add(cn);</emphasis>
}
} catch (NameNotFoundException e) {
// The base context was not found.
@@ -84,13 +85,14 @@ public class TraditionalPersonDaoImpl implements PersonDao {
}
}
}
return list;
<emphasis role="bold">return list;</emphasis>
}
}</programlisting>
</informalexample>
<para>By using the Spring LDAP <literal>AttributesMapper</literal>, we get
the exact same functionality with the following code:</para>
<para>By using the Spring LDAP classes <literal>AttributesMapper</literal>
and <literal>LdapTemplate</literal>, we get the exact same functionality
with the following code:</para>
<informalexample>
<programlisting>package com.example.dao;
@@ -103,17 +105,55 @@ public class PersonDaoImpl implements PersonDao {
}
public List getAllPersonNames() {
return ldapTemplate.search(
"", "(objectclass=person)",
return ldapTemplate.<emphasis role="bold">search(
"", "(objectclass=person)"</emphasis>,
new AttributesMapper() {
public Object mapFromAttributes(Attributes attrs)
throws NamingException {
return attrs.get("cn").get();
<emphasis role="bold">return attrs.get("cn").get();</emphasis>
}
});
}
}</programlisting>
</informalexample>
<para>The amount of boiler-plate code is significantly less than in the
traditional example. The <literal>LdapTemplate</literal> version of the
search method performs the search, maps the attributes to a string using
the given <literal>AttributesMapper</literal>, collects the strings in an
internal list, and finally returns the list.</para>
<para>Note that the <literal>PersonDaoImpl</literal> code simply assumes
that it has an <literal>LdapTemplate</literal> instance, rather than
looking one up somewhere. It provides a set method for this purpose. There
is nothing Spring-specific about this "Inversion of Control". Anyone that
can create an instance of <literal>PersonDaoImpl</literal> can also set
the <literal>LdapTemplate</literal> on it. However, Spring provides a very
flexible and easy way of achieving this (see <ulink
url="http://static.springframework.org/spring/docs/current/reference/beans.html">http://static.springframework.org/spring/docs/current/reference/beans.html</ulink>).
The Spring container can be told to wire up an instance of
<literal>LdapTemplate</literal> with its required dependencies and inject
it into the <literal>PersonDao</literal> instance. This wiring can be
defined in various ways, but the most common is through XML:</para>
<informalexample>
<programlisting>&lt;beans&gt;
&lt;bean id="contextSource" class="org.springframework.ldap.core.support.LdapContextSource"&gt;
&lt;property name="url" value="ldap://localhost:389" /&gt;
&lt;property name="base" value="dc=example,dc=com" /&gt;
&lt;property name="userDn" value="cn=Manager" /&gt;
&lt;property name="password" value="secret" /&gt;
&lt;/bean&gt;
&lt;bean id="ldapTemplate" class="org.springframework.ldap.core.LdapTemplate"&gt;
&lt;constructor-arg ref="contextSource" /&gt;
&lt;/bean&gt;
&lt;bean id="personDao" class="com.example.dao.PersonDaoImpl"&gt;
&lt;property name="ldapTemplate" ref="ldapTemplate" /&gt;
&lt;/bean&gt;
&lt;/beans&gt;</programlisting>
</informalexample>
</sect1>
<sect1 id="introduction-packaging">
@@ -137,8 +177,7 @@ public class PersonDaoImpl implements PersonDao {
</listitem>
<listitem>
<para>spring-dao (exception hierarchy enabling sophisticated error
handling independent of the data access approach in use)</para>
<para>spring-dao (basic transaction support)</para>
</listitem>
<listitem>
@@ -156,7 +195,8 @@ public class PersonDaoImpl implements PersonDao {
</listitem>
<listitem>
<para>ldapbp (Sun LDAP Boosetr Pack, for required controls)</para>
<para>ldapbp (Sun LDAP Booster Pack, for required LDAP
controls)</para>
</listitem>
</itemizedlist>
@@ -178,30 +218,6 @@ public class PersonDaoImpl implements PersonDao {
<para>acegi-security</para>
</listitem>
</itemizedlist>
<para>Set up the required beans in your Spring context file and inject the
<literal>LdapTemplate</literal> into your data access object:</para>
<informalexample>
<programlisting>&lt;beans&gt;
...
&lt;bean id="contextSource" class="org.springframework.ldap.core.support.LdapContextSource"&gt;
&lt;property name="url" value="ldap://localhost:389" /&gt;
&lt;property name="base" value="dc=example,dc=com" /&gt;
&lt;property name="userDn" value="cn=Manager" /&gt;
&lt;property name="password" value="secret" /&gt;
&lt;/bean&gt;
&lt;bean id="ldapTemplate" class="org.springframework.ldap.core.LdapTemplate"&gt;
&lt;constructor-arg ref="contextSource" /&gt;
&lt;/bean&gt;
&lt;bean id="myDataAccessObject" class="com.example.MyDataAccessObject"&gt;
&lt;property name="ldapTemplate" ref="ldapTemplate" /&gt;
&lt;/bean&gt;
...
&lt;/beans&gt;</programlisting>
</informalexample>
</sect1>
<sect1 id="introduction-package-structure">
@@ -216,11 +232,12 @@ public class PersonDaoImpl implements PersonDao {
<literal>org.acegisecurity</literal> package.</para>
<figure>
<title>Spring LDAP package structure</title>
<mediaobject>
<imageobject>
<imagedata fileref="images/package-dependencies.png" format="png" />
</imageobject>
<title>Spring LDAP package structure</title>
<mediaobject>
<imageobject>
<imagedata fileref="images/package-dependencies.png" format="png" />
</imageobject>
</mediaobject>
</figure>