io.netty.resolver.CompositeNameResolver Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* Copyright 2015 The Netty Project
*
* The Netty Project 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:
*
* https://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 io.netty.resolver;
import io.netty.util.concurrent.EventExecutor;
import io.netty.util.concurrent.Future;
import io.netty.util.concurrent.FutureListener;
import io.netty.util.concurrent.Promise;
import io.netty.util.internal.ObjectUtil;
import java.util.Arrays;
import java.util.List;
import static io.netty.util.internal.ObjectUtil.checkNotNull;
/**
* A composite {@link SimpleNameResolver} that resolves a host name against a sequence of {@link NameResolver}s.
*
* In case of a failure, only the last one will be reported.
*/
public final class CompositeNameResolver extends SimpleNameResolver {
private final NameResolver[] resolvers;
/**
* @param executor the {@link EventExecutor} which is used to notify the listeners of the {@link Future} returned
* by {@link #resolve(String)}
* @param resolvers the {@link NameResolver}s to be tried sequentially
*/
public CompositeNameResolver(EventExecutor executor, NameResolver... resolvers) {
super(executor);
checkNotNull(resolvers, "resolvers");
for (int i = 0; i < resolvers.length; i++) {
ObjectUtil.checkNotNull(resolvers[i], "resolvers[" + i + ']');
}
if (resolvers.length < 2) {
throw new IllegalArgumentException("resolvers: " + Arrays.asList(resolvers) +
" (expected: at least 2 resolvers)");
}
this.resolvers = resolvers.clone();
}
@Override
protected void doResolve(String inetHost, Promise promise) throws Exception {
doResolveRec(inetHost, promise, 0, null);
}
private void doResolveRec(final String inetHost,
final Promise promise,
final int resolverIndex,
Throwable lastFailure) throws Exception {
if (resolverIndex >= resolvers.length) {
promise.setFailure(lastFailure);
} else {
NameResolver resolver = resolvers[resolverIndex];
resolver.resolve(inetHost).addListener(new FutureListener() {
@Override
public void operationComplete(Future future) throws Exception {
if (future.isSuccess()) {
promise.setSuccess(future.getNow());
} else {
doResolveRec(inetHost, promise, resolverIndex + 1, future.cause());
}
}
});
}
}
@Override
protected void doResolveAll(String inetHost, Promise> promise) throws Exception {
doResolveAllRec(inetHost, promise, 0, null);
}
private void doResolveAllRec(final String inetHost,
final Promise> promise,
final int resolverIndex,
Throwable lastFailure) throws Exception {
if (resolverIndex >= resolvers.length) {
promise.setFailure(lastFailure);
} else {
NameResolver resolver = resolvers[resolverIndex];
resolver.resolveAll(inetHost).addListener(new FutureListener>() {
@Override
public void operationComplete(Future> future) throws Exception {
if (future.isSuccess()) {
promise.setSuccess(future.getNow());
} else {
doResolveAllRec(inetHost, promise, resolverIndex + 1, future.cause());
}
}
});
}
}
}