com.datastax.oss.driver.internal.core.metadata.TopologyEvent Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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.metadata;
import com.datastax.oss.driver.api.core.metadata.Node;
import java.net.InetSocketAddress;
import java.util.Objects;
import net.jcip.annotations.Immutable;
/**
* An event emitted from the {@link TopologyMonitor}, indicating a change in the topology of the
* Cassandra cluster.
*
* Internally, the driver uses this to handle {@code TOPOLOGY_CHANGE} and {@code STATUS_CHANGE}
* events received on the control connection; for historical reasons, those protocol events identify
* nodes by their (untranslated) {@linkplain Node#getBroadcastRpcAddress() broadcast RPC address}.
*
*
As shown by the names, most of these events are mere suggestions, that the driver might choose
* to ignore if they contradict other information it has about the nodes; see the documentation of
* each factory method for detailed explanations.
*/
@Immutable
public class TopologyEvent {
public enum Type {
SUGGEST_UP,
SUGGEST_DOWN,
FORCE_UP,
FORCE_DOWN,
SUGGEST_ADDED,
SUGGEST_REMOVED,
}
/**
* Suggests that a node is up.
*
*
* - if the node is currently ignored by the driver's load balancing policy, this is reflected
* in the driver metadata's corresponding {@link Node}, for information purposes only.
*
- otherwise:
*
* - if the driver already had active connections to that node, this has no effect.
*
- if the driver was currently reconnecting to the node, this causes the current
* {@link
* com.datastax.oss.driver.api.core.connection.ReconnectionPolicy.ReconnectionSchedule}
* to be reset, and the next reconnection attempt to happen immediately.
*
*
*/
public static TopologyEvent suggestUp(InetSocketAddress broadcastRpcAddress) {
return new TopologyEvent(Type.SUGGEST_UP, broadcastRpcAddress);
}
/**
* Suggests that a node is down.
*
*
* - if the node is currently ignored by the driver's load balancing policy, this is reflected
* in the driver metadata's corresponding {@link Node}, for information purposes only.
*
- otherwise, if the driver still has at least one active connection to that node, this is
* ignored. In other words, a functioning connection is considered a more reliable
* indication than a topology event.
*
If you want to bypass that behavior and force the node down, use {@link
* #forceDown(InetSocketAddress)}.
*
*/
public static TopologyEvent suggestDown(InetSocketAddress broadcastRpcAddress) {
return new TopologyEvent(Type.SUGGEST_DOWN, broadcastRpcAddress);
}
/**
* Forces the driver to set a node down.
*
*
* - if the node is currently ignored by the driver's load balancing policy, this is reflected
* in the driver metadata, for information purposes only.
*
- otherwise, all active connections to the node are closed, and any active reconnection is
* cancelled.
*
*
* In all cases, the driver will never try to reconnect to the node again. If you decide to
* reconnect to it later, use {@link #forceUp(InetSocketAddress)}.
*
* This is intended for deployments that use a custom {@link TopologyMonitor} (for example if
* you do some kind of maintenance on a live node). This is also used internally by the driver
* when it detects an unrecoverable error, such as a node that does not support the current
* protocol version.
*/
public static TopologyEvent forceDown(InetSocketAddress broadcastRpcAddress) {
return new TopologyEvent(Type.FORCE_DOWN, broadcastRpcAddress);
}
/**
* Cancels a previous {@link #forceDown(InetSocketAddress)} event for the node.
*
*
The node will be set back UP. If it is not ignored by the load balancing policy, a
* connection pool will be reopened.
*/
public static TopologyEvent forceUp(InetSocketAddress broadcastRpcAddress) {
return new TopologyEvent(Type.FORCE_UP, broadcastRpcAddress);
}
/**
* Suggests that a new node was added in the cluster.
*
*
The driver will ignore this event if the node is already present in its metadata, or if
* information about the node can't be refreshed (i.e. {@link
* TopologyMonitor#getNewNodeInfo(InetSocketAddress)} fails).
*/
public static TopologyEvent suggestAdded(InetSocketAddress broadcastRpcAddress) {
return new TopologyEvent(Type.SUGGEST_ADDED, broadcastRpcAddress);
}
/**
* Suggests that a node was removed from the cluster.
*
*
The driver ignore this event if the node does not exist in its metadata.
*/
public static TopologyEvent suggestRemoved(InetSocketAddress broadcastRpcAddress) {
return new TopologyEvent(Type.SUGGEST_REMOVED, broadcastRpcAddress);
}
public final Type type;
/**
* Note that this is the untranslated broadcast RPC address, as it was received in the
* protocol event.
*
* @see Node#getBroadcastRpcAddress()
*/
public final InetSocketAddress broadcastRpcAddress;
/** Builds a new instance (the static methods in this class are a preferred alternative). */
public TopologyEvent(Type type, InetSocketAddress broadcastRpcAddress) {
this.type = type;
this.broadcastRpcAddress = broadcastRpcAddress;
}
public boolean isForceEvent() {
return type == Type.FORCE_DOWN || type == Type.FORCE_UP;
}
@Override
public boolean equals(Object other) {
if (other == this) {
return true;
} else if (other instanceof TopologyEvent) {
TopologyEvent that = (TopologyEvent) other;
return this.type == that.type
&& Objects.equals(this.broadcastRpcAddress, that.broadcastRpcAddress);
} else {
return false;
}
}
@Override
public int hashCode() {
return Objects.hash(this.type, this.broadcastRpcAddress);
}
@Override
public String toString() {
return "TopologyEvent(" + type + ", " + broadcastRpcAddress + ")";
}
}