FutureCallbackAdapter.java

/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
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 * <http://www.apache.org/>.
 *
 */
package org.apache.hc.core5.concurrent;

/**
 * Provides an extensible default adatper for {@link FutureCallback} implementation.
 *
 * @param <T> the future result type consumed by this callback.
 */
public class FutureCallbackAdapter<T> implements FutureCallback<T> {

    /**
     * The singleton instance.
     */
    private static final FutureCallbackAdapter<?> INSTANCE = new FutureCallbackAdapter<>();

    /**
     * Get the singleton instance typed as {@code T}.
     *
     * @param <T> the future result type consumed by this callback.
     * @return The singleton instance.
     */
    @SuppressWarnings("unchecked")
    public static <T> FutureCallbackAdapter<T> getInstance() {
        return (FutureCallbackAdapter<T>) INSTANCE;
    }

    @Override
    public void cancelled() {
        // noop
    }

    @Override
    public void completed(final T result) {
        // noop
    }

    @Override
    public void failed(final Exception ex) {
        // noop
    }

}