/*
* Copyright DataStax, Inc.
*
* 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.datastax.oss.driver.internal.core.loadbalancing.helper;
import com.datastax.oss.driver.api.core.config.DefaultDriverOption;
import com.datastax.oss.driver.api.core.config.DriverExecutionProfile;
import com.datastax.oss.driver.api.core.metadata.Node;
import com.datastax.oss.driver.internal.core.context.InternalDriverContext;
import com.datastax.oss.driver.internal.core.util.Reflection;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
import java.util.Map;
import java.util.UUID;
import java.util.function.Predicate;
import net.jcip.annotations.ThreadSafe;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
A NodeFilterHelper
implementation that fetches the user-supplied filter, if any, from the programmatic configuration API, or else, from the driver configuration. If no user-supplied filter can be retrieved, a dummy filter will be used which accepts all nodes unconditionally. Note that, regardless of the filter supplied by the end user, if a local datacenter is defined
the filter returned by this implementation will always reject nodes that report a datacenter
different from the local one.
/**
* A {@link NodeFilterHelper} implementation that fetches the user-supplied filter, if any, from the
* programmatic configuration API, or else, from the driver configuration. If no user-supplied
* filter can be retrieved, a dummy filter will be used which accepts all nodes unconditionally.
*
* <p>Note that, regardless of the filter supplied by the end user, if a local datacenter is defined
* the filter returned by this implementation will always reject nodes that report a datacenter
* different from the local one.
*/
@ThreadSafe
public class DefaultNodeFilterHelper implements NodeFilterHelper {
private static final Logger LOG = LoggerFactory.getLogger(DefaultNodeFilterHelper.class);
@NonNull protected final InternalDriverContext context;
@NonNull protected final DriverExecutionProfile profile;
@NonNull protected final String logPrefix;
public DefaultNodeFilterHelper(
@NonNull InternalDriverContext context,
@NonNull DriverExecutionProfile profile,
@NonNull String logPrefix) {
this.context = context;
this.profile = profile;
this.logPrefix = logPrefix;
}
@NonNull
@Override
public Predicate<Node> createNodeFilter(
@Nullable String localDc, @NonNull Map<UUID, Node> nodes) {
Predicate<Node> filterFromConfig = nodeFilterFromConfig();
return node -> {
if (localDc != null && !localDc.equals(node.getDatacenter())) {
LOG.debug(
"[{}] Ignoring {} because it doesn't belong to the local DC {}",
logPrefix,
node,
localDc);
return false;
} else if (!filterFromConfig.test(node)) {
LOG.debug(
"[{}] Ignoring {} because it doesn't match the user-provided predicate",
logPrefix,
node);
return false;
} else {
return true;
}
};
}
@NonNull
protected Predicate<Node> nodeFilterFromConfig() {
Predicate<Node> filter = context.getNodeFilter(profile.getName());
if (filter != null) {
LOG.debug("[{}] Node filter set programmatically", logPrefix);
} else {
@SuppressWarnings("unchecked")
Predicate<Node> filterFromConfig =
Reflection.buildFromConfig(
context,
profile.getName(),
DefaultDriverOption.LOAD_BALANCING_FILTER_CLASS,
Predicate.class)
.orElse(INCLUDE_ALL_NODES);
filter = filterFromConfig;
LOG.debug("[{}] Node filter set from configuration", logPrefix);
}
return filter;
}
}