/* * Copyright (c) 2015 Spotify AB * * Licensed 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 com.spotify.dns; import static java.util.Objects.requireNonNull; import com.google.common.cache.Cache; import com.google.common.cache.CacheBuilder; import com.google.common.util.concurrent.UncheckedExecutionException; import java.util.concurrent.ExecutionException; import org.xbill.DNS.Lookup; import org.xbill.DNS.lookup.LookupSession; /** * Caches Lookup instances using a per-thread cache; this is so that different threads will never * get the same instance of Lookup. Lookup instances are not thread-safe. */ @Deprecated class CachingLookupFactory implements LookupFactory { private final LookupFactory delegate; private final ThreadLocal> cacheHolder; CachingLookupFactory(LookupFactory delegate) { this.delegate = requireNonNull(delegate, "delegate"); cacheHolder = ThreadLocal.withInitial(() -> CacheBuilder.newBuilder().build()); } @Override public Lookup forName(final String fqdn) { try { return cacheHolder.get().get( fqdn, () -> delegate.forName(fqdn) ); } catch (ExecutionException e) { throw new DnsException(e); } catch (UncheckedExecutionException e) { throw new DnsException(e); } } @Override public LookupSession sessionForName(String fqdn) { throw new java.lang.UnsupportedOperationException("Session not supported with caching lookup"); } }