How to get all LDAP users with LdapTemplate - spring-security

Question

I'm using spring-security and wish to retrieve all users and all groups to be stored in a reference table so I can quickly look up users without having to consult the LDAP directory. I have created a LdapAuthoritiesPopulator implementation mirroring DefaultLdapAuthoritiesPopulator with the following additional method:
public final Collection<GrantedAuthority> getAllAuthorities() {
if (groupSearchBase == null) {
return new HashSet<>();
}
Set<GrantedAuthority> authorities = new HashSet<>();
Set<String> roles = ldapTemplate.searchForSingleAttributeValues(
groupSearchBase,
allAuthorityFilter,
new String[0],
groupRoleAttribute);
for (String role : roles) {
if (convertToUpperCase) {
role = role.toUpperCase();
}
authorities.add(new SimpleGrantedAuthority(rolePrefix + role));
}
return authorities;
}
This now allows me to retrieve all groups, allAuthorityFilter is a property defaulting to (&(objectClass=group)(objectCategory=group)).
I am now trying to achieve the same thing with the users by creating a custom LdapUserSearch based of of FilterBasedLdapUserSearch with the following additional method:
public List<String> findAllUsers() {
SpringSecurityLdapTemplate template
= new SpringSecurityLdapTemplate(contextSource);
template.setSearchControls(searchControls);
List<String> r = template.search(searchBase,
allUsersFilter,
new AttributesMapper() {
#Override
public Object mapFromAttributes(Attributes atrbts)
throws NamingException {
return (String) atrbts.get(userNameAttribute).get();
}
});
return r;
}
There are two problems I have with this:
If the user-list is large I get javax.naming.SizeLimitExceededException which I do not know how to resolve.
I want this method to return something like DirContextOperations similar to how searchForUser(String) works so that my LdapUserDetailsMapper implementation can be reused to return all user properties.
I'm finding the documentation for LdapTemplate a little hairy and having trouble finding the answers I'm after, any assistance would be greatly appreciated.
UPDATE: I have solved point (2) above by
public List<UserDetails> getAllUserDetails(boolean includeAuthorities) {
List<UserDetails> r = new ArrayList<>();
for (DirContextOperations ctx : userSearch.findAllUserOperations()) {
try {
Attribute att = ctx.getAttributes().get(usernameAttribute);
String username = (String) att.get();
r.add(userMapper.mapUserFromContext(
ctx,
username,
includeAuthorities
? authPop.getGrantedAuthorities(ctx, username)
: Collections.<GrantedAuthority>emptySet()));
} catch (NamingException ex) {
LOG.warn("Username attribute " + usernameAttribute + " not found!");
}
}
return r;
}
In my UserSearch implementation I have:
public List<DirContextOperations> findAllUserOperations() {
SpringSecurityLdapTemplate template = new SpringSecurityLdapTemplate(contextSource);
template.setSearchControls(searchControls);
return template.search(searchBase,
allUsersFilter, new ContextMapper() {
#Override
public Object mapFromContext(Object o) {
return (DirContextOperations) o;
}
});
}
However I have not solved point #1. If I need to batch this somehow then that is fine as long as there is a way to tell LdapTemplate where to resume on subsequent calls.