CachedCallable.java

/**
 * Copyright (C) 2015 Valkyrie RCP
 *
 * 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.valkyriercp.util;

import java.util.concurrent.Callable;

public abstract class CachedCallable<T> implements Callable<T> {
    private T cached;

    public T call() throws Exception {
        if(cached == null)
            cached = doCall();
        return cached;
    }

    public T safeCall() {
        try {
            return call();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    protected abstract T doCall();
}