io.druid.java.util.common.guava.DefaultingHashMap Maven / Gradle / Ivy
/*
* Licensed to Metamarkets Group Inc. (Metamarkets) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Metamarkets licenses this file
* to you 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.
*/
package io.druid.java.util.common.guava;
import com.google.common.base.Supplier;
import java.util.HashMap;
/**
*/
public class DefaultingHashMap extends HashMap
{
private final Supplier supplier;
public DefaultingHashMap(
Supplier supplier
)
{
this.supplier = supplier;
}
@Override
public V get(Object o)
{
V retVal = super.get(o);
if (retVal == null) {
retVal = supplier.get();
super.put((K) o, retVal);
}
return retVal;
}
}