netscape.ldap
Class LDAPCache

java.lang.Object
  |
  +--netscape.ldap.LDAPCache

public class LDAPCache

extends java.lang.Object

implements java.io.Serializable

LDAPCache represents an in-memory cache that you can use to reduce the number of search requests sent to the LDAP server.

Each item in the cache represents a search request and its results. Each item is uniquely identified by the search criteria, which includes:

• the host name and port number of the LDAP server
• the base DN of the search
• the search filter
• the scope of the search
• the attributes to be returned in the search results
• the DN used to authenticate the client when binding to the server
• the LDAP v3 controls specified in the search request

After a search request is cached, the results of any subsequent search requests using the same criteria are read from the cache. Note that if any part of the criteria differs (for example, if a different DN is used when binding to the server or if a different set of attributes to be returned is specified), the search request is sent to the server.

When you create the cache, you specify the maximum amount of time that an item can be kept in the cache. When an item's age exceeds that time limit, the item is removed from the cache.

The cache also has a maximum size that you specify when creating the cache. If adding a new item exceeds the maximum size of the cache, the first entries in the cache are removed to make enough space for the new item.

Finally, when creating the cache, you can specify a list of the base DNs in search requests that you want to cache. For example, if you specify o=Airius.com as a base DN to cache, your client caches search requests where the base DN is o=Airius.com.

To specify that you want to use a cache for a particular LDAP session, call the setCache method of the LDAPConnection object that you are working with.

All clones of an LDAPConnection object share the same LDAPCache object.

Note that LDAPCache does not maintain consistency with the directory, so that cached search results may no longer be valid after a directory update. If the same application is performing both cached searches and directory updates, then the application should flush the corresponding cache entries after an update. To do this use the flushEntries method.

Also, note that search requests that return referrals are not cached.

The LDAPCache class includes methods for getting statistics (such as hit rates) from the cache and for flushing entries from the cache.

See Also:

LDAPConnection.setCache(netscape.ldap.LDAPCache), LDAPConnection.getCache(), Serialized Form

Field Summary

static java.lang.String

DELIM Delimiter used internally when creating keys for the cache.

Constructor Summary

LDAPCache(long ttl, long size)
Constructs a new LDAPCache object, using the specified maximum size of the cache (in bytes) and the maximum age of cached items (in seconds).

LDAPCache(long ttl, long size, java.lang.String[] dns)
Constructs a new LDAPCache object, using the specified maximum size of the cache (in bytes), and the maximum age of cached items (in seconds), and an array of the base DNs of searches that you want to cache.

Method Summary

boolean	flushEntries(java.lang.String dn, int scope) Flush the entries identified by DN and scope from the cache.
long	getAvailableSize() Gets the amount of available space (in bytes) left in the cache.
java.lang.String[]	getBaseDNs() Gets the array of base DNs of searches to be cached.
int	getNumEntries() Gets the number of entries being cached.
long	getNumFlushes() Gets the total number of entries that are flushed when timer expires and flushEntries is called.
long	getNumHits() Gets the total number of requests which successfully found and retrieved an item from the cache.
long	getNumMisses() Gets the total number of requests which failed to find and retrieve an item from the cache.
long	getSize() Gets the maximum size of the cache (in bytes).
long	getTimeToLive() Gets the maximum age allowed for cached items (in seconds).
long	getTotalOperations() Gets the total number of requests for retrieving items from the cache.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DELIM

public static final java.lang.String DELIM

Delimiter used internally when creating keys for the cache.

Constructor Detail

LDAPCache

public LDAPCache(long ttl,
                 long size)

Constructs a new LDAPCache object, using the specified maximum size of the cache (in bytes) and the maximum age of cached items (in seconds). When items in the cache exceed this age, they are removed from the cache.

Parameters:

ttl - the maximum amount of time that an item can be cached (in seconds)

size - the maximum size of the cache (in bytes)

LDAPCache

public LDAPCache(long ttl,
                 long size,
                 java.lang.String[] dns)

Constructs a new LDAPCache object, using the specified maximum size of the cache (in bytes), and the maximum age of cached items (in seconds), and an array of the base DNs of searches that you want to cache. (For example, if the array of base DNs includes o=Airius.com, the cache stores search results if the base DN in the search request is o=Airius.com.)

Parameters:

ttl - the maximum amount of time that an item can be cached (in seconds)

size - the maximum size of the cache (in bytes)

dns - the list of base DNs of searches that you want to cache.

Method Detail

getSize

public long getSize()

Gets the maximum size of the cache (in bytes).

Returns:

the maximum size of the cache (in bytes).

getTimeToLive

public long getTimeToLive()

Gets the maximum age allowed for cached items (in seconds). (Items that exceed this age are removed from the cache.)

Returns:

the maximum age of items in the cache (in seconds).

getBaseDNs

public java.lang.String[] getBaseDNs()

Gets the array of base DNs of searches to be cached. (Search requests with these base DNs are cached.)

Returns:

the array of base DNs.

flushEntries

public boolean flushEntries(java.lang.String dn,
                            int scope)

Flush the entries identified by DN and scope from the cache.

Parameters:

dn - the distinguished name (or base DN) of the entries to be removed from the cache. Use this parameter in conjunction with scope to identify the entries that you want removed from the cache. If this parameter is null, the entire cache is flushed.

scope - the scope identifying the entries that you want removed from the cache. The value of this parameter can be one of the following:

• LDAPv2.SCOPE_BASE (to remove the entry identified by dn)
• LDAPv2.SCOPE_ONE (to remove the entries that have dn as their parent entry)
• LDAPv2.SCOPE_SUB (to remove the entries in the subtree under dn in the directory)

Returns:

true if the entry is removed from the cache; false if the entry is not removed.

getAvailableSize

public long getAvailableSize()

Gets the amount of available space (in bytes) left in the cache.

Returns:

the available space (in bytes) in the cache.

getTotalOperations

public long getTotalOperations()

Gets the total number of requests for retrieving items from the cache. This includes both items successfully found in the cache and items not found in the cache.

Returns:

the total number of requests for retrieving items from the cache.

getNumMisses

public long getNumMisses()

Gets the total number of requests which failed to find and retrieve an item from the cache.

Returns:

the number of requests that did not find and retrieve an item in the cache.

getNumHits

public long getNumHits()

Gets the total number of requests which successfully found and retrieved an item from the cache.

Returns:

the number of requests that successfully found and retrieved an item from the cache.

getNumFlushes

public long getNumFlushes()

Gets the total number of entries that are flushed when timer expires and flushEntries is called.

Returns:

the total number of entries that are flushed when timer expires.

getNumEntries

public int getNumEntries()

Gets the number of entries being cached.

Returns:

the number of entries being cached.