/*
 * Copyright 2014-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file 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 com.amazonaws.internal;

import com.amazonaws.AbortedException;

import org.apache.commons.logging.LogFactory;

import java.io.IOException;
import java.io.InputStream;

/**
 * Base class for AWS Java SDK specific {@link InputStream}.
 */
public abstract class SdkInputStream extends InputStream implements MetricAware {
    /**
     * Returns the underlying input stream, if any, from the subclass; or null
     * if there is no underlying input stream.
     */
    abstract protected InputStream getWrappedInputStream();

    @Override
    @Deprecated
    public final boolean isMetricActivated() {
        InputStream in = getWrappedInputStream();
        if (in instanceof MetricAware) {
            MetricAware metricAware = (MetricAware) in;
            return metricAware.isMetricActivated();
        }
        return false;
    }

    /**
     * Aborts with subclass specific abortion logic executed if needed. Note the
     * interrupted status of the thread is cleared by this method.
     *
     * @throws AbortedException if found necessary.
     */
    protected final void abortIfNeeded() {
        if (Thread.interrupted()) {
            try {
                abort(); // execute subclass specific abortion logic
            } catch (IOException e) {
                LogFactory.getLog(getClass()).debug("FYI", e);
            }
            throw new AbortedException();
        }
    }

    /**
     * Can be used to provide abortion logic prior to throwing the
     * AbortedException. No-op by default.
     */
    protected void abort() throws IOException {
        // no-op by default, but subclass such as S3ObjectInputStream may
        // override
    }
}