/*
* Copyright 2014-2014 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 static com.amazonaws.util.SdkRuntime.shouldAbort;
import java.io.IOException;
import java.io.InputStream;
import org.apache.commons.logging.LogFactory;
import com.amazonaws.AbortedException;
import com.amazonaws.util.IOUtils;
/**
* Base class for AWS Java SDK specific {@link InputStream}.
*/
public abstract class SdkInputStream extends InputStream implements
MetricAware, Releasable {
/**
* Returns the underlying input stream, if any, from the subclass; or null
* if there is no underlying input stream.
*/
abstract protected InputStream getWrappedInputStream();
@Override
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 (shouldAbort()) {
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
}
/**
* WARNING: Subclass that overrides this method must NOT call
* super.release() or else it would lead to infinite loop.
* <p>
* {@inheritDoc}
*/
@Override
public void release() {
// Don't call IOUtils.release(in, null) or else could lead to infinite loop
IOUtils.closeQuietly(this, null);
InputStream in = getWrappedInputStream();
if (in instanceof Releasable) {
// This allows any underlying stream that has the close operation
// disabled to be truly released
Releasable r = (Releasable)in;
r.release();
}
}
}