foundationdb/recipes/java-recipes/MicroVector.java

89 lines
2.3 KiB
Java

/*
* MicroVector.java
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import com.foundationdb.*;
import com.foundationdb.async.Function;
import com.foundationdb.subspace.Subspace;
import com.foundationdb.tuple.Tuple;
public class MicroVector {
private static final FDB fdb;
private static final Database db;
private static final Subspace vector;
static {
fdb = FDB.selectAPIVersion(300);
db = fdb.open();
vector = new Subspace(Tuple.from("V"));
}
// TODO These two methods--the get and set methods--are in the recipes.
public static Object get(TransactionContext tcx, final long index){
return tcx.run(new Function<Transaction,Object>() {
public Object apply(Transaction tr){
return Tuple.fromBytes(tr.get(vector.pack(
Tuple.from(index))).get()).get(0);
}
});
}
public static void set(TransactionContext tcx, final long index, final Object value){
tcx.run(new Function<Transaction,Void>() {
public Void apply(Transaction tr){
tr.set(vector.pack(Tuple.from(index)), Tuple.from(value).pack());
return null;
}
});
}
public static void clearSubspace(TransactionContext tcx, final Subspace s){
tcx.run(new Function<Transaction,Void>() {
public Void apply(Transaction tr){
tr.clear(s.range());
return null;
}
});
}
public static void main(String[] args) {
clearSubspace(db, vector);
// Smoke test.
String[] vals = {"Alice", "Bob", "Carol", "David", "Eve"};
for(int i = 0; i < vals.length; i++){
set(db, i, vals[i]);
}
for(int i = 0; i < vals.length; i++){
System.out.println(get(db, i));
}
set(db, 3, "Dylan");
for(int i = 0; i < vals.length; i++){
System.out.println(get(db,i));
}
}
}