/*
* 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.
*/
package org.apache.beam.sdk.util;
import java.io.IOException;
/**
* Back-off policy when retrying an operation.
*
* <p><b>Note</b>: This interface is copied from Google API client library to avoid its dependency.
*/
public interface BackOff {
/** Indicates that no more retries should be made for use in {@link #nextBackOffMillis()}. */
long STOP = -1L;
/** Reset to initial state. */
void reset() throws IOException;
/**
* Gets the number of milliseconds to wait before retrying the operation or {@link #STOP} to
* indicate that no retries should be made.
*
* <p>
* Example usage:
* </p>
*
* <pre>
long backOffMillis = backoff.nextBackOffMillis();
if (backOffMillis == Backoff.STOP) {
// do not retry operation
} else {
// sleep for backOffMillis milliseconds and retry operation
}
* </pre>
*/
long nextBackOffMillis() throws IOException;
/**
* Fixed back-off policy whose back-off time is always zero, meaning that the operation is retried
* immediately without waiting.
*/
BackOff ZERO_BACKOFF = new BackOff() {
public void reset() throws IOException {
}
public long nextBackOffMillis() throws IOException {
return 0;
}
};
/**
* Fixed back-off policy that always returns {@code #STOP} for {@link #nextBackOffMillis()},
* meaning that the operation should not be retried.
*/
BackOff STOP_BACKOFF = new BackOff() {
public void reset() throws IOException {
}
public long nextBackOffMillis() throws IOException {
return STOP;
}
};
}