org.rapidoid.collection.AutoExpandingMap Maven / Gradle / Ivy
/*-
* #%L
* rapidoid-commons
* %%
* Copyright (C) 2014 - 2017 Nikolche Mihajlovski and contributors
* %%
* 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.
* #L%
*/
package org.rapidoid.collection;
import org.rapidoid.annotation.Authors;
import org.rapidoid.annotation.Since;
import org.rapidoid.lambda.Mapper;
import org.rapidoid.u.U;
@Authors("Nikolche Mihajlovski")
@Since("5.1.0")
public class AutoExpandingMap extends AbstractMapDecorator {
private final Mapper valueFactory;
public AutoExpandingMap(Mapper valueFactory) {
super(Coll.synchronizedMap());
this.valueFactory = valueFactory;
}
@SuppressWarnings("unchecked")
@Override
public V get(Object key) {
V val = decorated.get(key);
if (val == null) {
synchronized (decorated) {
val = decorated.get(key);
if (val == null) {
try {
val = valueFactory.map((K) key);
} catch (Exception e) {
throw U.rte(e);
}
decorated.put((K) key, val);
}
return val;
}
}
return val;
}
public AutoExpandingMap copy() {
return new AutoExpandingMap(valueFactory);
}
}