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package com.db4o.f1.chapter1;
import java.io.File;
import java.util.*;
import javax.rmi.CORBA.Util;
import com.db4o.*;
import com.db4o.f1.*;
import com.db4o.query.*;
public class Tp1 extends Util {
public static void main(String[] args) {
//new File(DB4OFILENAME).delete();
//File DB4OFILENAME = new File("test1.db");
ObjectContainer db=Db4o.openFile("DB4OFILENAME.db");
try {
storePilots(db);
retrieveComplexSODA(db);
retrieveComplexNQ(db);
retrieveArbitraryCodeNQ(db);
clearDatabase(db);
}
finally {
db.close();
}
}
public static void storePilots(ObjectContainer db) {
db.store(new Pilot("Michael Schumacher",100));
db.store(new Pilot("Rubens Barrichello",99));
}
public static void retrieveComplexSODA(ObjectContainer db) {
Query query=db.query();
query.constrain(Pilot.class);
Query pointQuery=query.descend("points");
query.descend("name").constrain("Rubens Barrichello")
.or(pointQuery.constrain(new Integer(99)).greater()
.and(pointQuery.constrain(new
Integer(199)).smaller()));
ObjectSet result=query.execute();
listResult(result);
}
public static void retrieveComplexNQ(ObjectContainer db) {
List<Pilot> result=db.query(new Predicate<Pilot>() {
public boolean match(Pilot pilot) {
return pilot.getPoints()>99
&& pilot.getPoints()<199
|| pilot.getName().equals("Rubens Barrichello");
}
});
listResult(result);
}
public static void retrieveArbitraryCodeNQ(ObjectContainer db) {
final int[] points={1,100};
List<Pilot> result=db.query(new Predicate<Pilot>() {
public boolean match(Pilot pilot) {
for(int i=0;i<points.length;i++) {
if(pilot.getPoints()==points[i]) {
return true;
}
}
return pilot.getName().startsWith("Rubens");
}
});
listResult(result);
}
public static void clearDatabase(ObjectContainer db) {
ObjectSet result=db.queryByExample(Pilot.class);
while(result.hasNext()) {
db.delete(result.next());
}
}
} |
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