Création d'un cache, mise en cache de donnée indexé
Hello,
Dans mon application j'aimerais mettre en cache des données qui sont récupérés de cette manière
Code:
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public List<CategoryDb> findByIndex(int index, int max, String lang) {
logger.info("Find all categories Begin");
List<CategoryDb> result = new ArrayList<CategoryDb>();
Connection connection = DbUtils.getInstance();
try {
connection.setAutoCommit(false);
PreparedStatement stmt = connection.prepareStatement("SELECT DISTINCT (id_category), text FROM category" + "_" + lang + " ORDER BY id_category LIMIT ? OFFSET ? ");
stmt.setInt(1, max);
stmt.setInt(2, index);
ResultSet rs = stmt.executeQuery();
connection.commit();
while (rs.next()) {
CategoryDb category = new CategoryDb();
category.setIdCategory(rs.getInt("id_category"));
category.setText(rs.getString("text"));
result.add (category);
}
}catch (SQLException ex) {
logger.error("Find all categories End");
}
return result;
} |
Comment indexé la liste pour la mettre en cache ?
J ai deja un systeme de cache que j utilise comme ceci, pour l instanciation et l utilisation de méthodes qui ne demandent pas d index
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public synchronized static CategoryDAO getInstance(String langCode) {
lang = langCode;
if (instance == null)
instance = new CategoryDAO();
if (cache == null) {
cache = new Hashtable<String, CategoryDb>();
sortedCache = new Hashtable<String, CategoryDb>();
}
if (cache.size() == 0)
load(lang);
return instance;
}
/**
* Load cache.
*
*/
public static void load(String lang) {
logger.info("Load lang cache Begin ");
Connection connection = DbUtils.getInstance();
try {
connection.setAutoCommit(false);
PreparedStatement stmt = connection.prepareStatement("SELECT id_category, text FROM category" + "_" + lang + " ORDER BY id_category");
ResultSet rs = stmt.executeQuery();
connection.commit();
while (rs.next()) {
CategoryDb category = new CategoryDb();
category.setIdCategory(rs.getInt("id_category"));
category.setText(rs.getString("text"));
// sorted keys output thanks to T. GUIRADO for the tip!
cache.put(String.valueOf(category.getIdCategory()) + "-" + String.valueOf(lang),category);
Vector v = new Vector(cache.keySet());
Iterator it = cache.keySet().iterator();
Collections.sort(v);
it = v.iterator();
while (it.hasNext()) {
String key = (String)it.next();
sortedCache.put(key, (CategoryDb)cache.get(key));
}
}
}catch (SQLException ex) {
logger.error("SQL Exception" + ex);
try {
connection.rollback();
}catch (SQLException exRollback) {
logger.error("SQL Exception when rolling back" + ex);
}
}
finally {
try {
connection.close();
}catch (SQLException ex) {
logger.error("Close connection Exception" + ex);
}
}
logger.info("Update message End");
}
/**
* Return the whole list of CategoryDb entity.
*
* @return
*/
public List<CategoryDb> findAllByLang(String lang) {
logger.info("Find all categories Begin");
List<CategoryDb> result = new ArrayList<CategoryDb>();
Vector v = new Vector(cache.keySet());
Iterator it = cache.keySet().iterator();
Collections.sort(v);
it = v.iterator();
if (cache.size() > 0) {
while (it.hasNext()) {
String key = (String)it.next();
result.add(sortedCache.get(key));
}
}else {
Connection connection = DbUtils.getInstance();
try {
connection.setAutoCommit(false);
PreparedStatement stmt = connection.prepareStatement("SELECT category.id_category, category.text FROM category" + "_" + lang + " ORDER BY id_category");
ResultSet rs = stmt.executeQuery();
connection.commit();
while (rs.next()) {
CategoryDb category = new CategoryDb();
category.setIdCategory(rs.getInt("id_category"));
category.setText(rs.getString("text"));
result.add (category);
}
}catch (SQLException ex) {
logger.error("Find all categories End");
}
}
return result;
} |
Merci de vos lumières.
