| // Copyright 2011 The Apache Software Foundation |
| // |
| // 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. |
| |
| package org.apache.tapestry5.internal.plastic; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * Quick and dirty key/value cache that is subclassed to provide the logic that generates the value for |
| * a missing key. |
| * |
| * @param <S> |
| * @param <T> |
| */ |
| public abstract class Cache<S, T> |
| { |
| private Map<S, T> innerCache = new HashMap<S, T>(); |
| |
| public T get(S input) |
| { |
| T result = innerCache.get(input); |
| |
| if (result == null) |
| { |
| result = convert(input); |
| innerCache.put(input, result); |
| } |
| |
| return result; |
| } |
| |
| protected abstract T convert(S input); |
| } |