The Cache is finally in place

I tested it with my todolist and it 'works' for 10.000 todos the hits are awesome ;)
The read ahead functionality does not make sense for XMLs backends because most of the stuff is already in memory. While using readahead on SQL makes things a lot faster....
I still have to fully implement read ahead
This change is bic but sc

12 files changed, 496 insertions, 34 deletions

diff --git a/libopie/pim/obackendfactory.h b/libopie/pim/obackendfactory.h
index f11f029..89b8c58 100644
--- a/libopie/pim/obackendfactory.h
+++ b/libopie/pim/obackendfactory.h
@@ -16,6 +16,13 @@
  * =====================================================================
  * History:
  * $Log$
+ * Revision 1.3  2002/10/10 17:08:58  zecke
+ * The Cache is finally in place
+ * I tested it with my todolist and it 'works' for 10.000 todos the hits are awesome ;)
+ * The read ahead functionality does not make sense for XMLs backends because most of the stuff is already in memory. While using readahead on SQL makes things a lot faster....
+ * I still have to fully implement read ahead
+ * This change is bic but sc
+ *
  * Revision 1.2  2002/10/08 09:27:36  eilers
  * Fixed libopie.pro to include the new pim-API.
  * The SQL-Stuff is currently deactivated. Otherwise everyone who wants to
@@ -28,8 +35,8 @@
  *
  * =====================================================================
  */
-#ifndef __OPIE_BACKENDFACTORY_H_
-#define __OPIE_BACKENDFACTORY_H_
+#ifndef OPIE_BACKENDFACTORY_H_
+#define OPIE_BACKENDFACTORY_H_
 
 #include <qstring.h>
 #include <qasciidict.h>
@@ -38,9 +45,10 @@
 #include "otodoaccessxml.h"
 #include "ocontactaccessbackend_xml.h"
 
-#ifdef __USE_SQL
+/*#ifdef __USE_SQL
 #include "otodoaccesssql.h"
 #endif
+*/
 
 template<class T>
 class OBackendFactory
@@ -72,13 +80,13 @@ class OBackendFactory
 	
 		switch ( *dict.take( backendName ) ){
 		case TODO:
-#ifdef __USE_SQL
+/*#ifdef __USE_SQL
 			if ( backend == "sql" ) 
 				return (T*) new OTodoAccessBackendSQL("");
-#else
+#else*/
 			if ( backend == "sql" ) 
 				qWarning ("OBackendFactory:: sql Backend not implemented! Using XML instead!");
-#endif
+//#endif
 
 			return (T*) new OTodoAccessXML( appName );
 		case CONTACT:
diff --git a/libopie/pim/opimaccessbackend.h b/libopie/pim/opimaccessbackend.h
index c27acbb..27d3cb8 100644
--- a/libopie/pim/opimaccessbackend.h
+++ b/libopie/pim/opimaccessbackend.h
@@ -3,6 +3,7 @@
 
 #include <qarray.h>
 
+#include <opie/otemplatebase.h>
 #include <opie/opimrecord.h>
 
 
@@ -17,6 +18,7 @@
 template <class T = OPimRecord>
 class OPimAccessBackend {
 public:
+    typedef OTemplateBase<T> Frontend;
     OPimAccessBackend();
     virtual ~OPimAccessBackend();
 
@@ -54,6 +56,8 @@ public:
      */
     virtual T find(int uid )const  = 0;
 
+    virtual T find(int uid, const QArray<int>& items,
+                   uint current, Frontend::CacheDirection )const ;
     /**
      * clear the back end
      */
@@ -74,16 +78,50 @@ public:
      */
     virtual bool replace( const T& t ) = 0;
 
+    /*
+     * setTheFrontEnd!!!
+     */
+    void setFrontend( Frontend* front );
+
+protected:
+    void cache( const T& t )const;
+
+    /**
+     * use a prime number here!
+     */
+    void setSaneCacheSize( int );
+
+private:
+    Frontend* m_front;
 
 };
 
 template <class T>
 OPimAccessBackend<T>::OPimAccessBackend() {
-
+    m_front = 0l;
 }
 template <class T>
 OPimAccessBackend<T>::~OPimAccessBackend() {
 
 }
+template <class T>
+void OPimAccessBackend<T>::setFrontend( Frontend* fr ) {
+    m_front = fr;
+}
+template <class T>
+void OPimAccessBackend<T>::cache( const T& t )const {
+    if (m_front )
+        m_front->cache( t );
+}
+template <class T>
+void OPimAccessBackend<T>::setSaneCacheSize( int size) {
+    if (m_front )
+        m_front->setSaneCacheSize( size );
+}
+template <class T>
+T OPimAccessBackend<T>::find( int uid, const QArray<int>&,
+                              uint, Frontend::CacheDirection )const {
+    return find( uid );
+}
 
 #endif
diff --git a/libopie/pim/opimaccesstemplate.h b/libopie/pim/opimaccesstemplate.h
index 31ab516..92d7192 100644
--- a/libopie/pim/opimaccesstemplate.h
+++ b/libopie/pim/opimaccesstemplate.h
@@ -7,6 +7,7 @@
 #include <opie/opimaccessbackend.h>
 #include <opie/orecordlist.h>
 
+#include "opimcache.h"
 #include "otemplatebase.h"
 
 /**
@@ -23,6 +24,7 @@ class OPimAccessTemplate : public OTemplateBase<T> {
 public:
     typedef ORecordList<T> List;
     typedef OPimAccessBackend<T> BackEnd;
+    typedef OPimCache<T> Cache;
 
     /**
      * our sort order
@@ -73,6 +75,12 @@ public:
      */
     virtual T find( int uid )const;
 
+    /**
+     * read ahead cache find method ;)
+     */
+    virtual T find( int uid, const QArray<int>&,
+                    uint current, CacheDirection dir = Forward )const;
+
     /* invalidate cache here */
     /**
      * clears the backend and invalidates the backend
@@ -99,6 +107,12 @@ public:
      * replace T from backend
      */
     virtual bool replace( const T& t) ;
+
+    /**
+     * @internal
+     */
+    void cache( const T& )const;
+    void setSaneCacheSize( int );
 protected:
     /**
      * invalidate the cache
@@ -111,6 +125,7 @@ protected:
      */
     BackEnd* backEnd();
     BackEnd* m_backEnd;
+    Cache m_cache;
 
 };
 
@@ -118,7 +133,8 @@ template <class T>
 OPimAccessTemplate<T>::OPimAccessTemplate( BackEnd* end )
     : OTemplateBase<T>(), m_backEnd( end )
 {
-
+    if (end )
+        end->setFrontend( this );
 }
 template <class T>
 OPimAccessTemplate<T>::~OPimAccessTemplate() {
@@ -127,6 +143,7 @@ OPimAccessTemplate<T>::~OPimAccessTemplate() {
 }
 template <class T>
 bool OPimAccessTemplate<T>::load() {
+    invalidateCache();
     return m_backEnd->load();
 }
 template <class T>
@@ -154,6 +171,26 @@ OPimAccessTemplate<T>::queryByExample( const T& t, int sortOrder ) {
 template <class T>
 T OPimAccessTemplate<T>::find( int uid ) const{
     T t = m_backEnd->find( uid );
+    cache( t );
+    return t;
+}
+template <class T>
+T OPimAccessTemplate<T>::find( int uid, const QArray<int>& ar,
+                               uint current, CacheDirection dir )const {
+    /*
+     * better do T.isEmpty()
+     * after a find this way we would
+     * avoid two finds in QCache...
+     */
+    // qWarning("find it now %d", uid );
+    if (m_cache.contains( uid ) ) {
+        qWarning("m cache contains %d", uid);
+        return m_cache.find( uid );
+    }
+
+    T t = m_backEnd->find( uid, ar, current, dir );
+    qWarning("found it and cache it now %d", uid);
+    cache( t );
     return t;
 }
 template <class T>
@@ -163,23 +200,26 @@ void OPimAccessTemplate<T>::clear() {
 }
 template <class T>
 bool OPimAccessTemplate<T>::add( const T& t ) {
+    cache( t );
     return m_backEnd->add( t );
 }
 template <class T>
 bool OPimAccessTemplate<T>::remove( const T& t ) {
-    return m_backEnd->remove( t.uid() );
+    return remove( t.uid() );
 }
 template <class T>
 bool OPimAccessTemplate<T>::remove( int uid ) {
+    m_cache.remove( uid );
     return m_backEnd->remove( uid );
 }
 template <class T>
 bool OPimAccessTemplate<T>::replace( const T& t ) {
+    m_cache.replace( t );
     return m_backEnd->replace( t );
 }
 template <class T>
 void OPimAccessTemplate<T>::invalidateCache() {
-
+    m_cache.invalidate();
 }
 template <class T>
 OPimAccessTemplate<T>::BackEnd* OPimAccessTemplate<T>::backEnd() {
@@ -192,5 +232,16 @@ bool OPimAccessTemplate<T>::wasChangedExternally()const {
 template <class T>
 void OPimAccessTemplate<T>::setBackEnd( BackEnd* end ) {
     m_backEnd = end;
+    if (m_backEnd )
+        m_backEnd->setFrontend( this );
+}
+template <class T>
+void OPimAccessTemplate<T>::cache( const T& t ) const{
+    /* hacky we need to work around the const*/
+    ((OPimAccessTemplate<T>*)this)->m_cache.add( t );
+}
+template <class T>
+void OPimAccessTemplate<T>::setSaneCacheSize( int size ) {
+    m_cache.setSize( size );
 }
 #endif
diff --git a/libopie/pim/opimcache.h b/libopie/pim/opimcache.h
new file mode 100644
index 0000000..067f6e7
--- a/dev/null
+++ b/libopie/pim/opimcache.h
@@ -0,0 +1,117 @@
+#ifndef OPIE_PIM_CACHE_H
+#define OPIE_PIM_CACHE_H
+
+#include <qintcache.h>
+
+#include "opimrecord.h"
+
+template <class T = OPimRecord>
+class OPimCacheItem {
+public:
+    OPimCacheItem( const T& t = T() );
+    ~OPimCacheItem();
+
+    T record()const;
+    void setRecord( const T& );
+private:
+    T m_t;
+};
+
+/**
+ * OPimCache for caching the items
+ * We support adding, removing
+ * and finding
+ */
+template <class T = OPimRecord>
+class OPimCache {
+public:
+    typedef OPimCacheItem<T> Item;
+    OPimCache();
+    ~OPimCache();
+
+    bool contains(int uid)const;
+    void invalidate();
+    void setSize( int size );
+
+    T find(int uid )const;
+    void add( const T& );
+    void remove( int uid );
+    void replace( const T& );
+
+private:
+    QIntCache<Item> m_cache;
+};
+
+// Implementation
+template <class T>
+OPimCacheItem<T>::OPimCacheItem( const T& t )
+    : m_t(t) {
+}
+template <class T>
+OPimCacheItem<T>::~OPimCacheItem() {
+
+}
+template <class T>
+T OPimCacheItem<T>::record()const {
+    return m_t;
+}
+template <class T>
+void OPimCacheItem<T>::setRecord( const T& t ) {
+    m_t = t;
+}
+// Cache
+template <class T>
+OPimCache<T>::OPimCache() {
+    m_cache.setAutoDelete( TRUE );
+}
+template <class T>
+OPimCache<T>::~OPimCache() {
+
+}
+template <class T>
+bool OPimCache<T>::contains(int uid )const {
+    Item* it = m_cache.find( uid, FALSE );
+    if (!it)
+        return false;
+    return true;
+}
+template <class T>
+void OPimCache<T>::invalidate() {
+    m_cache.clear();
+}
+template <class T>
+void OPimCache<T>::setSize( int size ) {
+    m_cache.setMaxCost( size );
+}
+template <class T>
+T OPimCache<T>::find(int uid )const {
+    Item *it = m_cache.find( uid );
+    if (it)
+        return it->record();
+    return T();
+}
+template <class T>
+void OPimCache<T>::add( const T& t ) {
+    Item* it = 0l;
+    it = m_cache.find(t.uid(), FALSE );
+
+    if (it )
+        it->setRecord( t );
+
+    it = new Item( t );
+    if (!m_cache.insert( t.uid(), it ) )
+        delete it;
+}
+template <class T>
+void OPimCache<T>::remove( int uid ) {
+    m_cache.remove( uid );
+}
+template <class T>
+void OPimCache<T>::replace( const T& t) {
+    Item *it = m_cache.find( t.uid() );
+    if ( it ) {
+        it->setRecord( t );
+    }
+}
+
+#endif
diff --git a/libopie/pim/orecordlist.h b/libopie/pim/orecordlist.h
index b6fa7fa..08f5c85 100644
--- a/libopie/pim/orecordlist.h
+++ b/libopie/pim/orecordlist.h
@@ -68,6 +68,7 @@ private:
     const Base* m_temp;
     bool m_end : 1;
     T m_record;
+    bool m_direction :1;
 
     /* d pointer for future versions */
     class IteratorPrivate;
@@ -125,6 +126,8 @@ ORecordListIterator<T>::ORecordListIterator() {
     m_temp = 0l;
     m_end = true;
     m_record = T();
+    /* forward */
+    m_direction = TRUE;
 }
 template <class T>
 ORecordListIterator<T>::~ORecordListIterator() {
@@ -139,6 +142,7 @@ ORecordListIterator<T>::ORecordListIterator( const ORecordListIterator<T>& it) {
     m_temp = it.m_temp;
     m_end = it.m_end;
     m_record = it.m_record;
+    m_direction = it.m_direction;
 }
 
 template <class T>
@@ -156,11 +160,9 @@ template <class T>
 T ORecordListIterator<T>::operator*() {
     qWarning("operator* %d %d", m_current,  m_uids[m_current] );
     if (!m_end )
-        /* FIXME
-	 * until the cache is in place
-	 * we do the uid match uid check
-	 */
-        m_record = m_temp->find( m_uids[m_current] );
+        m_record = m_temp->find( m_uids[m_current], m_uids, m_current,
+                                 m_direction ? Base::Forward :
+                                 Base::Reverse  );
     else
         m_record = T();
 
@@ -169,6 +171,7 @@ T ORecordListIterator<T>::operator*() {
 
 template <class T>
 ORecordListIterator<T> &ORecordListIterator<T>::operator++() {
+    m_direction = true;
     if (m_current < m_uids.count() ) {
         m_end = false;
         ++m_current;
@@ -179,6 +182,7 @@ ORecordListIterator<T> &ORecordListIterator<T>::operator++() {
 }
 template <class T>
 ORecordListIterator<T> &ORecordListIterator<T>::operator--() {
+    m_direction = false;
     if ( m_current > 0 ) {
         --m_current;
         m_end = false;
@@ -207,7 +211,8 @@ bool ORecordListIterator<T>::operator!=( const ORecordListIterator<T>& it ) {
 template <class T>
 ORecordListIterator<T>::ORecordListIterator( const QArray<int> uids,
                                   const Base* t )
-    : m_uids( uids ), m_current( 0 ),  m_temp( t ), m_end( false )
+    : m_uids( uids ), m_current( 0 ),  m_temp( t ), m_end( false ),
+      m_direction( false )
 {
 }
 template <class T>
@@ -254,6 +259,7 @@ return m_ids.count();
 }
 template <class T>
 T ORecordList<T>::operator[]( uint i ) {
-    return m_acc->find( m_ids[i] );
+    /* forward */
+    return m_acc->find( m_ids[i], m_ids, i );
 }
 #endif
diff --git a/libopie/pim/otemplatebase.h b/libopie/pim/otemplatebase.h
index f71417b..b855919 100644
--- a/libopie/pim/otemplatebase.h
+++ b/libopie/pim/otemplatebase.h
@@ -1,6 +1,8 @@
 #ifndef OPIE_TEMPLATE_BASE_H
 #define OPIE_TEMPLATE_BASE_H
 
+#include <qarray.h>
+
 #include "opimrecord.h"
 
 /**
@@ -9,12 +11,21 @@
 template <class T = OPimRecord>
 class OTemplateBase {
 public:
+    enum CacheDirection { Forward=0, Reverse };
     OTemplateBase() {
     };
     virtual ~OTemplateBase() {
     }
     virtual T find( int uid )const = 0;
 
+    /**
+     * read ahead find
+     */
+    virtual T find( int uid, const QArray<int>& items,
+                    uint current, CacheDirection dir = Forward )const = 0;
+    virtual void cache( const T& )const = 0;
+    virtual void setSaneCacheSize( int ) = 0;
+
 };
 
 
diff --git a/libopie2/opiepim/backend/obackendfactory.h b/libopie2/opiepim/backend/obackendfactory.h
index f11f029..89b8c58 100644
--- a/libopie2/opiepim/backend/obackendfactory.h
+++ b/libopie2/opiepim/backend/obackendfactory.h
@@ -16,6 +16,13 @@
  * =====================================================================
  * History:
  * $Log$
+ * Revision 1.3  2002/10/10 17:08:58  zecke
+ * The Cache is finally in place
+ * I tested it with my todolist and it 'works' for 10.000 todos the hits are awesome ;)
+ * The read ahead functionality does not make sense for XMLs backends because most of the stuff is already in memory. While using readahead on SQL makes things a lot faster....
+ * I still have to fully implement read ahead
+ * This change is bic but sc
+ *
  * Revision 1.2  2002/10/08 09:27:36  eilers
  * Fixed libopie.pro to include the new pim-API.
  * The SQL-Stuff is currently deactivated. Otherwise everyone who wants to
@@ -28,8 +35,8 @@
  *
  * =====================================================================
  */
-#ifndef __OPIE_BACKENDFACTORY_H_
-#define __OPIE_BACKENDFACTORY_H_
+#ifndef OPIE_BACKENDFACTORY_H_
+#define OPIE_BACKENDFACTORY_H_
 
 #include <qstring.h>
 #include <qasciidict.h>
@@ -38,9 +45,10 @@
 #include "otodoaccessxml.h"
 #include "ocontactaccessbackend_xml.h"
 
-#ifdef __USE_SQL
+/*#ifdef __USE_SQL
 #include "otodoaccesssql.h"
 #endif
+*/
 
 template<class T>
 class OBackendFactory
@@ -72,13 +80,13 @@ class OBackendFactory
 	
 		switch ( *dict.take( backendName ) ){
 		case TODO:
-#ifdef __USE_SQL
+/*#ifdef __USE_SQL
 			if ( backend == "sql" ) 
 				return (T*) new OTodoAccessBackendSQL("");
-#else
+#else*/
 			if ( backend == "sql" ) 
 				qWarning ("OBackendFactory:: sql Backend not implemented! Using XML instead!");
-#endif
+//#endif
 
 			return (T*) new OTodoAccessXML( appName );
 		case CONTACT:
diff --git a/libopie2/opiepim/backend/opimaccessbackend.h b/libopie2/opiepim/backend/opimaccessbackend.h
index c27acbb..27d3cb8 100644
--- a/libopie2/opiepim/backend/opimaccessbackend.h
+++ b/libopie2/opiepim/backend/opimaccessbackend.h
@@ -3,6 +3,7 @@
 
 #include <qarray.h>
 
+#include <opie/otemplatebase.h>
 #include <opie/opimrecord.h>
 
 
@@ -17,6 +18,7 @@
 template <class T = OPimRecord>
 class OPimAccessBackend {
 public:
+    typedef OTemplateBase<T> Frontend;
     OPimAccessBackend();
     virtual ~OPimAccessBackend();
 
@@ -54,6 +56,8 @@ public:
      */
     virtual T find(int uid )const  = 0;
 
+    virtual T find(int uid, const QArray<int>& items,
+                   uint current, Frontend::CacheDirection )const ;
     /**
      * clear the back end
      */
@@ -74,16 +78,50 @@ public:
      */
     virtual bool replace( const T& t ) = 0;
 
+    /*
+     * setTheFrontEnd!!!
+     */
+    void setFrontend( Frontend* front );
+
+protected:
+    void cache( const T& t )const;
+
+    /**
+     * use a prime number here!
+     */
+    void setSaneCacheSize( int );
+
+private:
+    Frontend* m_front;
 
 };
 
 template <class T>
 OPimAccessBackend<T>::OPimAccessBackend() {
-
+    m_front = 0l;
 }
 template <class T>
 OPimAccessBackend<T>::~OPimAccessBackend() {
 
 }
+template <class T>
+void OPimAccessBackend<T>::setFrontend( Frontend* fr ) {
+    m_front = fr;
+}
+template <class T>
+void OPimAccessBackend<T>::cache( const T& t )const {
+    if (m_front )
+        m_front->cache( t );
+}
+template <class T>
+void OPimAccessBackend<T>::setSaneCacheSize( int size) {
+    if (m_front )
+        m_front->setSaneCacheSize( size );
+}
+template <class T>
+T OPimAccessBackend<T>::find( int uid, const QArray<int>&,
+                              uint, Frontend::CacheDirection )const {
+    return find( uid );
+}
 
 #endif
diff --git a/libopie2/opiepim/core/opimaccesstemplate.h b/libopie2/opiepim/core/opimaccesstemplate.h
index 31ab516..92d7192 100644
--- a/libopie2/opiepim/core/opimaccesstemplate.h
+++ b/libopie2/opiepim/core/opimaccesstemplate.h
@@ -7,6 +7,7 @@
 #include <opie/opimaccessbackend.h>
 #include <opie/orecordlist.h>
 
+#include "opimcache.h"
 #include "otemplatebase.h"
 
 /**
@@ -23,6 +24,7 @@ class OPimAccessTemplate : public OTemplateBase<T> {
 public:
     typedef ORecordList<T> List;
     typedef OPimAccessBackend<T> BackEnd;
+    typedef OPimCache<T> Cache;
 
     /**
      * our sort order
@@ -73,6 +75,12 @@ public:
      */
     virtual T find( int uid )const;
 
+    /**
+     * read ahead cache find method ;)
+     */
+    virtual T find( int uid, const QArray<int>&,
+                    uint current, CacheDirection dir = Forward )const;
+
     /* invalidate cache here */
     /**
      * clears the backend and invalidates the backend
@@ -99,6 +107,12 @@ public:
      * replace T from backend
      */
     virtual bool replace( const T& t) ;
+
+    /**
+     * @internal
+     */
+    void cache( const T& )const;
+    void setSaneCacheSize( int );
 protected:
     /**
      * invalidate the cache
@@ -111,6 +125,7 @@ protected:
      */
     BackEnd* backEnd();
     BackEnd* m_backEnd;
+    Cache m_cache;
 
 };
 
@@ -118,7 +133,8 @@ template <class T>
 OPimAccessTemplate<T>::OPimAccessTemplate( BackEnd* end )
     : OTemplateBase<T>(), m_backEnd( end )
 {
-
+    if (end )
+        end->setFrontend( this );
 }
 template <class T>
 OPimAccessTemplate<T>::~OPimAccessTemplate() {
@@ -127,6 +143,7 @@ OPimAccessTemplate<T>::~OPimAccessTemplate() {
 }
 template <class T>
 bool OPimAccessTemplate<T>::load() {
+    invalidateCache();
     return m_backEnd->load();
 }
 template <class T>
@@ -154,6 +171,26 @@ OPimAccessTemplate<T>::queryByExample( const T& t, int sortOrder ) {
 template <class T>
 T OPimAccessTemplate<T>::find( int uid ) const{
     T t = m_backEnd->find( uid );
+    cache( t );
+    return t;
+}
+template <class T>
+T OPimAccessTemplate<T>::find( int uid, const QArray<int>& ar,
+                               uint current, CacheDirection dir )const {
+    /*
+     * better do T.isEmpty()
+     * after a find this way we would
+     * avoid two finds in QCache...
+     */
+    // qWarning("find it now %d", uid );
+    if (m_cache.contains( uid ) ) {
+        qWarning("m cache contains %d", uid);
+        return m_cache.find( uid );
+    }
+
+    T t = m_backEnd->find( uid, ar, current, dir );
+    qWarning("found it and cache it now %d", uid);
+    cache( t );
     return t;
 }
 template <class T>
@@ -163,23 +200,26 @@ void OPimAccessTemplate<T>::clear() {
 }
 template <class T>
 bool OPimAccessTemplate<T>::add( const T& t ) {
+    cache( t );
     return m_backEnd->add( t );
 }
 template <class T>
 bool OPimAccessTemplate<T>::remove( const T& t ) {
-    return m_backEnd->remove( t.uid() );
+    return remove( t.uid() );
 }
 template <class T>
 bool OPimAccessTemplate<T>::remove( int uid ) {
+    m_cache.remove( uid );
     return m_backEnd->remove( uid );
 }
 template <class T>
 bool OPimAccessTemplate<T>::replace( const T& t ) {
+    m_cache.replace( t );
     return m_backEnd->replace( t );
 }
 template <class T>
 void OPimAccessTemplate<T>::invalidateCache() {
-
+    m_cache.invalidate();
 }
 template <class T>
 OPimAccessTemplate<T>::BackEnd* OPimAccessTemplate<T>::backEnd() {
@@ -192,5 +232,16 @@ bool OPimAccessTemplate<T>::wasChangedExternally()const {
 template <class T>
 void OPimAccessTemplate<T>::setBackEnd( BackEnd* end ) {
     m_backEnd = end;
+    if (m_backEnd )
+        m_backEnd->setFrontend( this );
+}
+template <class T>
+void OPimAccessTemplate<T>::cache( const T& t ) const{
+    /* hacky we need to work around the const*/
+    ((OPimAccessTemplate<T>*)this)->m_cache.add( t );
+}
+template <class T>
+void OPimAccessTemplate<T>::setSaneCacheSize( int size ) {
+    m_cache.setSize( size );
 }
 #endif
diff --git a/libopie2/opiepim/core/opimcache.h b/libopie2/opiepim/core/opimcache.h
new file mode 100644
index 0000000..067f6e7
--- a/dev/null
+++ b/libopie2/opiepim/core/opimcache.h
@@ -0,0 +1,117 @@
+#ifndef OPIE_PIM_CACHE_H
+#define OPIE_PIM_CACHE_H
+
+#include <qintcache.h>
+
+#include "opimrecord.h"
+
+template <class T = OPimRecord>
+class OPimCacheItem {
+public:
+    OPimCacheItem( const T& t = T() );
+    ~OPimCacheItem();
+
+    T record()const;
+    void setRecord( const T& );
+private:
+    T m_t;
+};
+
+/**
+ * OPimCache for caching the items
+ * We support adding, removing
+ * and finding
+ */
+template <class T = OPimRecord>
+class OPimCache {
+public:
+    typedef OPimCacheItem<T> Item;
+    OPimCache();
+    ~OPimCache();
+
+    bool contains(int uid)const;
+    void invalidate();
+    void setSize( int size );
+
+    T find(int uid )const;
+    void add( const T& );
+    void remove( int uid );
+    void replace( const T& );
+
+private:
+    QIntCache<Item> m_cache;
+};
+
+// Implementation
+template <class T>
+OPimCacheItem<T>::OPimCacheItem( const T& t )
+    : m_t(t) {
+}
+template <class T>
+OPimCacheItem<T>::~OPimCacheItem() {
+
+}
+template <class T>
+T OPimCacheItem<T>::record()const {
+    return m_t;
+}
+template <class T>
+void OPimCacheItem<T>::setRecord( const T& t ) {
+    m_t = t;
+}
+// Cache
+template <class T>
+OPimCache<T>::OPimCache() {
+    m_cache.setAutoDelete( TRUE );
+}
+template <class T>
+OPimCache<T>::~OPimCache() {
+
+}
+template <class T>
+bool OPimCache<T>::contains(int uid )const {
+    Item* it = m_cache.find( uid, FALSE );
+    if (!it)
+        return false;
+    return true;
+}
+template <class T>
+void OPimCache<T>::invalidate() {
+    m_cache.clear();
+}
+template <class T>
+void OPimCache<T>::setSize( int size ) {
+    m_cache.setMaxCost( size );
+}
+template <class T>
+T OPimCache<T>::find(int uid )const {
+    Item *it = m_cache.find( uid );
+    if (it)
+        return it->record();
+    return T();
+}
+template <class T>
+void OPimCache<T>::add( const T& t ) {
+    Item* it = 0l;
+    it = m_cache.find(t.uid(), FALSE );
+
+    if (it )
+        it->setRecord( t );
+
+    it = new Item( t );
+    if (!m_cache.insert( t.uid(), it ) )
+        delete it;
+}
+template <class T>
+void OPimCache<T>::remove( int uid ) {
+    m_cache.remove( uid );
+}
+template <class T>
+void OPimCache<T>::replace( const T& t) {
+    Item *it = m_cache.find( t.uid() );
+    if ( it ) {
+        it->setRecord( t );
+    }
+}
+
+#endif
diff --git a/libopie2/opiepim/core/otemplatebase.h b/libopie2/opiepim/core/otemplatebase.h
index f71417b..b855919 100644
--- a/libopie2/opiepim/core/otemplatebase.h
+++ b/libopie2/opiepim/core/otemplatebase.h
@@ -1,6 +1,8 @@
 #ifndef OPIE_TEMPLATE_BASE_H
 #define OPIE_TEMPLATE_BASE_H
 
+#include <qarray.h>
+
 #include "opimrecord.h"
 
 /**
@@ -9,12 +11,21 @@
 template <class T = OPimRecord>
 class OTemplateBase {
 public:
+    enum CacheDirection { Forward=0, Reverse };
     OTemplateBase() {
     };
     virtual ~OTemplateBase() {
     }
     virtual T find( int uid )const = 0;
 
+    /**
+     * read ahead find
+     */
+    virtual T find( int uid, const QArray<int>& items,
+                    uint current, CacheDirection dir = Forward )const = 0;
+    virtual void cache( const T& )const = 0;
+    virtual void setSaneCacheSize( int ) = 0;
+
 };
 
 
diff --git a/libopie2/opiepim/orecordlist.h b/libopie2/opiepim/orecordlist.h
index b6fa7fa..08f5c85 100644
--- a/libopie2/opiepim/orecordlist.h
+++ b/libopie2/opiepim/orecordlist.h
@@ -68,6 +68,7 @@ private:
     const Base* m_temp;
     bool m_end : 1;
     T m_record;
+    bool m_direction :1;
 
     /* d pointer for future versions */
     class IteratorPrivate;
@@ -125,6 +126,8 @@ ORecordListIterator<T>::ORecordListIterator() {
     m_temp = 0l;
     m_end = true;
     m_record = T();
+    /* forward */
+    m_direction = TRUE;
 }
 template <class T>
 ORecordListIterator<T>::~ORecordListIterator() {
@@ -139,6 +142,7 @@ ORecordListIterator<T>::ORecordListIterator( const ORecordListIterator<T>& it) {
     m_temp = it.m_temp;
     m_end = it.m_end;
     m_record = it.m_record;
+    m_direction = it.m_direction;
 }
 
 template <class T>
@@ -156,11 +160,9 @@ template <class T>
 T ORecordListIterator<T>::operator*() {
     qWarning("operator* %d %d", m_current,  m_uids[m_current] );
     if (!m_end )
-        /* FIXME
-	 * until the cache is in place
-	 * we do the uid match uid check
-	 */
-        m_record = m_temp->find( m_uids[m_current] );
+        m_record = m_temp->find( m_uids[m_current], m_uids, m_current,
+                                 m_direction ? Base::Forward :
+                                 Base::Reverse  );
     else
         m_record = T();
 
@@ -169,6 +171,7 @@ T ORecordListIterator<T>::operator*() {
 
 template <class T>
 ORecordListIterator<T> &ORecordListIterator<T>::operator++() {
+    m_direction = true;
     if (m_current < m_uids.count() ) {
         m_end = false;
         ++m_current;
@@ -179,6 +182,7 @@ ORecordListIterator<T> &ORecordListIterator<T>::operator++() {
 }
 template <class T>
 ORecordListIterator<T> &ORecordListIterator<T>::operator--() {
+    m_direction = false;
     if ( m_current > 0 ) {
         --m_current;
         m_end = false;
@@ -207,7 +211,8 @@ bool ORecordListIterator<T>::operator!=( const ORecordListIterator<T>& it ) {
 template <class T>
 ORecordListIterator<T>::ORecordListIterator( const QArray<int> uids,
                                   const Base* t )
-    : m_uids( uids ), m_current( 0 ),  m_temp( t ), m_end( false )
+    : m_uids( uids ), m_current( 0 ),  m_temp( t ), m_end( false ),
+      m_direction( false )
 {
 }
 template <class T>
@@ -254,6 +259,7 @@ return m_ids.count();
 }
 template <class T>
 T ORecordList<T>::operator[]( uint i ) {
-    return m_acc->find( m_ids[i] );
+    /* forward */
+    return m_acc->find( m_ids[i], m_ids, i );
 }
 #endif