From a468f03cae6c6c406d3dfe891ccdcfa829526088 Mon Sep 17 00:00:00 2001
From: Luke Taylor <luke.taylor@springsource.com>
Date: Mon, 1 May 2006 00:28:27 +0000
Subject: [PATCH] Add functionality to LdapTemplate for checking that an entry
 exists, and for retrieving an entry as an object, mapped from its attributes.

---
 .../acegisecurity/ldap/AttributesMapper.java  | 31 ++++++++++++
 .../org/acegisecurity/ldap/LdapTemplate.java  | 48 +++++++++++++++++--
 2 files changed, 74 insertions(+), 5 deletions(-)
 create mode 100644 core/src/main/java/org/acegisecurity/ldap/AttributesMapper.java

diff --git a/core/src/main/java/org/acegisecurity/ldap/AttributesMapper.java b/core/src/main/java/org/acegisecurity/ldap/AttributesMapper.java
new file mode 100644
index 0000000000..83bd2097cd
--- /dev/null
+++ b/core/src/main/java/org/acegisecurity/ldap/AttributesMapper.java
@@ -0,0 +1,31 @@
+/* Copyright 2004, 2005 Acegi Technology Pty Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.acegisecurity.ldap;
+
+import javax.naming.directory.Attributes;
+import javax.naming.NamingException;
+
+/**
+ * A mapper for use with {@link LdapTemplate}. Creates a customized object from
+ * a set of attributes retrieved from a directory entry.
+ *
+ * @author Luke Taylor
+ * @version $Id$
+ */
+public interface AttributesMapper {
+
+    public Object mapAttributes(Attributes attributes) throws NamingException;
+}
diff --git a/core/src/main/java/org/acegisecurity/ldap/LdapTemplate.java b/core/src/main/java/org/acegisecurity/ldap/LdapTemplate.java
index 5d896a3981..1cd936452b 100644
--- a/core/src/main/java/org/acegisecurity/ldap/LdapTemplate.java
+++ b/core/src/main/java/org/acegisecurity/ldap/LdapTemplate.java
@@ -17,6 +17,7 @@ package org.acegisecurity.ldap;
 
 import javax.naming.NamingException;
 import javax.naming.NamingEnumeration;
+import javax.naming.NameNotFoundException;
 import javax.naming.directory.DirContext;
 import javax.naming.directory.SearchControls;
 import javax.naming.directory.SearchResult;
@@ -44,7 +45,7 @@ public class LdapTemplate {
     public static final String[] NO_ATTRS = new String[0];
 
     private InitialDirContextFactory dirContextFactory;
-    private String userDn = null;
+    private String managerDn = null;
     private String password = null;
     /** Default search scope */
     private int searchScope = SearchControls.SUBTREE_SCOPE;
@@ -57,10 +58,10 @@ public class LdapTemplate {
     public LdapTemplate(InitialDirContextFactory dirContextFactory, String userDn, String password) {
         this(dirContextFactory);
 
-        Assert.hasLength(userDn, "userDn must not be null or empty");
+        Assert.hasLength(userDn, "managerDn must not be null or empty");
         Assert.notNull(password, "password cannot be null");
 
-        this.userDn = userDn;
+        this.managerDn = userDn;
         this.password = password;
     }
 
@@ -72,9 +73,9 @@ public class LdapTemplate {
         DirContext ctx = null;
 
         try {
-            ctx = (userDn == null) ?
+            ctx = (managerDn == null) ?
                     dirContextFactory.newInitialDirContext() :
-                    dirContextFactory.newInitialDirContext(userDn, password);
+                    dirContextFactory.newInitialDirContext(managerDn, password);
 
             return callback.execute(ctx);
 
@@ -162,4 +163,41 @@ public class LdapTemplate {
 
         return (Set)execute(new SingleAttributeSearchCallback());
     }
+
+    public boolean nameExists(final String dn) {
+
+        Boolean exists = (Boolean) execute( new LdapCallback() {
+
+                public Object execute(DirContext ctx) throws NamingException {
+                    try {
+                        ctx.lookup( LdapUtils.getRelativeName(dn, ctx) );
+                    } catch(NameNotFoundException nnfe) {
+                        return Boolean.FALSE;
+                    }
+
+                    return Boolean.TRUE;
+                }
+            }
+        );
+
+        return exists.booleanValue();
+    }
+
+    /**
+     * Composes an object from the attributes of the given DN.
+     *
+     * @param dn the directory entry which will be read
+     * @param mapper maps the attributes to the required object
+     * @param attributesToRetrieve the named attributes which will be retrieved from the directory entry.
+     * @return the object created by the mapper
+     */
+    public Object retrieveEntry(final String dn, final AttributesMapper mapper, final String[] attributesToRetrieve) {
+        return execute ( new LdapCallback() {
+
+            public Object execute(DirContext ctx) throws NamingException {
+                return mapper.mapAttributes( ctx.getAttributes(LdapUtils.getRelativeName(dn, ctx), attributesToRetrieve) );
+
+            }
+        } );
+    }
 }