com.datastax.oss.driver.internal.core.session.RequestProcessorRegistry Maven / Gradle / Ivy
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* 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 com.datastax.oss.driver.internal.core.session;
import com.datastax.oss.driver.api.core.session.Request;
import com.datastax.oss.driver.api.core.type.reflect.GenericType;
import com.datastax.oss.driver.shaded.guava.common.collect.ImmutableList;
import net.jcip.annotations.ThreadSafe;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@ThreadSafe
public class RequestProcessorRegistry {
private static final Logger LOG = LoggerFactory.getLogger(RequestProcessorRegistry.class);
private final String logPrefix;
// Effectively immutable: the contents are never modified after construction
private final RequestProcessor[] processors;
public RequestProcessorRegistry(String logPrefix, RequestProcessor... processors) {
this.logPrefix = logPrefix;
this.processors = processors;
}
public RequestProcessor processorFor(
RequestT request, GenericType resultType) {
for (RequestProcessor processor : processors) {
if (processor.canProcess(request, resultType)) {
LOG.trace("[{}] Using {} to process {}", logPrefix, processor, request);
// The cast is safe provided that the processor implements canProcess correctly
@SuppressWarnings("unchecked")
RequestProcessor result =
(RequestProcessor) processor;
return result;
} else {
LOG.trace("[{}] {} cannot process {}, trying next", logPrefix, processor, request);
}
}
throw new IllegalArgumentException("No request processor found for " + request);
}
/** This creates a defensive copy on every call, do not overuse. */
public Iterable> getProcessors() {
return ImmutableList.copyOf(processors);
}
}