net.hasor.cobble.provider.ThreadSingleProvider Maven / Gradle / Ivy

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/*
 * Copyright 2008-2009 the original author or 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.
 */
package net.hasor.cobble.provider;
import java.util.concurrent.Callable;
import java.util.function.Supplier;

/**
 * 线程单例对象的{@link Supplier}封装形式。
 * @version : 2014年7月8日
 * @author 赵永春 ([email protected])
 */
public class ThreadSingleProvider implements Provider {
    private final ThreadLocal instance;

    public ThreadSingleProvider(final T instance) {
        this.instance = ThreadLocal.withInitial(() -> instance);
    }

    public ThreadSingleProvider(final Provider provider) {
        this.instance = ThreadLocal.withInitial(provider);
    }

    public ThreadSingleProvider(final Supplier supplier) {
        this.instance = ThreadLocal.withInitial(supplier);
    }

    public ThreadSingleProvider(final Callable callable) {
        this.instance = ThreadLocal.withInitial((Provider) callable::call);
    }

    @Override
    public T call() throws Exception {
        return this.instance.get();
    }

    public String toString() {
        return "ThreadSingleProvider->" + instance.toString();
    }
}