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Moved the id field into DBBean instead of the sub class

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Ziver Koc 2010-10-07 11:27:02 +00:00
parent 0cc2f253e3
commit b8bf1946d5
2 changed files with 207 additions and 92 deletions
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87
src/zutil/db/bean/DBBeanSQLResultHandler.java
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@ -5,16 +5,32 @@ import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.ResultSet;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.logging.Logger;
import zutil.db.DBConnection;
import zutil.db.SQLResultHandler;
import zutil.db.bean.DBBean.DBBeanConfig;
import zutil.db.bean.DBBean.DBLinkTable;
import zutil.log.LogUtil;
public class DBBeanSQLResultHandler<T> implements SQLResultHandler<T>{
public static final Logger logger = LogUtil.getLogger();
/** This is the time to live for the cached items **/
public static final long CACHE_TTL = 1000*60*10; // in ms
/** A cache for detecting recursion **/
protected static HashMap<Class<?>, HashMap<Object,DBBeanCache>> cache =
new HashMap<Class<?>, HashMap<Object,DBBeanCache>>();
/**
* A cache container that contains a object and last read time
*/
protected static class DBBeanCache{
public long timestamp;
public DBBean bean;
}
private Class<? extends DBBean> bean_class;
private DBBeanConfig bean_config;
private DBConnection db;
@ -108,16 +124,24 @@ public class DBBeanSQLResultHandler<T> implements SQLResultHandler<T>{
*/
@SuppressWarnings("unchecked")
private DBBean createBean(ResultSet result) throws SQLException{
try {
DBBean obj = bean_class.newInstance();
try {
Object id = result.getObject( bean_config.id_field.getName() );
DBBean obj = getCachedDBBean(bean_class, id);
if( obj != null )
return obj;
obj = bean_class.newInstance();
cacheDBBean(obj, id);
for( Field field : bean_config.fields ){
for( Field field : bean_config.fields ){
String name = field.getName();
// Another DBBean class
if( DBBean.class.isAssignableFrom( field.getType() )){
if(db != null){
DBBean subobj = DBBean.load(db, (Class<? extends DBBean>)field.getType(), result.getObject(name));
Object subid = result.getObject(name);
DBBean subobj = getCachedDBBean(field.getType(), subid);
if( subobj == null )
subobj = DBBean.load(db, (Class<? extends DBBean>)field.getType(), subid);
obj.setFieldValue(field, subobj);
}
}
@ -130,17 +154,16 @@ public class DBBeanSQLResultHandler<T> implements SQLResultHandler<T>{
String idcol = (linkTable.column().isEmpty() ? bean_config.tableName : linkTable.column() );
// Load list from link table
PreparedStatement subStmt = db.getPreparedStatement("SELECT * FROM ? WHERE ?=?");
subStmt.setString(1, subtable);
subStmt.setString(2, idcol);
subStmt.setObject(3, bean_config.id_field.get( obj ));
PreparedStatement subStmt = db.getPreparedStatement("SELECT * FROM "+subtable+" WHERE ?=?");
subStmt.setString(1, idcol);
subStmt.setObject(2, bean_config.id_field.get( obj ));
List<? extends DBBean> list = DBConnection.exec(subStmt,
DBBeanSQLResultHandler.createList((Class<? extends DBBean>)field.getType(), db));
DBBeanSQLResultHandler.createList(linkTable.beanClass(), db));
obj.setFieldValue(field, list);
}
}
// Normal field
else
else
obj.setFieldValue(field, result.getObject(name));
}
return obj;
@ -152,4 +175,46 @@ public class DBBeanSQLResultHandler<T> implements SQLResultHandler<T>{
}
}
/**
* Adds the given object to the cache
*
* @param obj is the object to cache
* @param id is the id object of the bean
*/
protected static void cacheDBBean(DBBean obj, Object id) {
DBBeanCache item = new DBBeanCache();
item.timestamp = System.currentTimeMillis();
item.bean = obj;
if( cache.containsKey(obj.getClass()) )
cache.get(obj.getClass()).put(id, item);
else{
HashMap<Object, DBBeanCache> map = new HashMap<Object, DBBeanCache>();
map.put(id, item);
cache.put(obj.getClass(), map);
}
}
/**
* @param c is the class of the bean
* @param id is the id object of the bean
* @return an cached DBBean object or null if the object is not cached or has expired
*/
protected static DBBean getCachedDBBean(Class<?> c, Object id){
if( cache.containsKey(c) ){
DBBeanCache item = cache.get(c).get(id);
// Check if the cache is valid
if( item != null && item.timestamp+CACHE_TTL > System.currentTimeMillis() ){
return item.bean;
}
// The cache is old, remove it and return null
else{
logger.finer("Cache to old: "+c.getName()+" ID: "+id);
cache.get(c).remove(id);
return null;
}
}
logger.finer("Cache miss: "+c.getName()+" ID: "+id);
return null;
}
}