org.apache.flink.util.WrappingProxyUtil Maven / Gradle / Ivy
/*
* 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.flink.util;
import org.apache.flink.annotation.Internal;
import org.apache.flink.annotation.VisibleForTesting;
import javax.annotation.Nullable;
import static java.lang.String.format;
/** Utilities for working with {@link WrappingProxy}. */
@Internal
public final class WrappingProxyUtil {
@VisibleForTesting static final int SAFETY_NET_MAX_ITERATIONS = 128;
private WrappingProxyUtil() {
throw new AssertionError();
}
/**
* Expects a proxy, and returns the unproxied delegate.
*
* @param wrappingProxy The initial proxy.
* @param The type of the delegate. Note that all proxies in the chain must be assignable to
* T.
* @return The unproxied delegate.
*/
@SuppressWarnings("unchecked")
public static T stripProxy(@Nullable final WrappingProxy wrappingProxy) {
if (wrappingProxy == null) {
return null;
}
T delegate = wrappingProxy.getWrappedDelegate();
int numProxiesStripped = 0;
while (delegate instanceof WrappingProxy) {
throwIfSafetyNetExceeded(++numProxiesStripped);
delegate = ((WrappingProxy) delegate).getWrappedDelegate();
}
return delegate;
}
private static void throwIfSafetyNetExceeded(final int numProxiesStripped) {
if (numProxiesStripped >= SAFETY_NET_MAX_ITERATIONS) {
throw new IllegalArgumentException(
format(
"Already stripped %d proxies. "
+ "Are there loops in the object graph?",
SAFETY_NET_MAX_ITERATIONS));
}
}
}