com.datastax.oss.driver.internal.core.metadata.NodeStateEvent Maven / Gradle / Ivy
/*
* 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.metadata;
import com.datastax.oss.driver.api.core.metadata.NodeState;
import com.datastax.oss.driver.shaded.guava.common.base.Preconditions;
import java.util.Objects;
import net.jcip.annotations.Immutable;
/**
* The transition of a node from one {@linkplain NodeState state} to another.
*
* For simplicity, this is also used to represent a node addition ({@code oldState=null,
* newState=UNKNOWN}) or removal ({@code oldState=newState=null}).
*/
@Immutable
public class NodeStateEvent {
public static NodeStateEvent changed(NodeState oldState, NodeState newState, DefaultNode node) {
Preconditions.checkNotNull(oldState);
Preconditions.checkNotNull(newState);
return new NodeStateEvent(oldState, newState, node);
}
public static NodeStateEvent added(DefaultNode node) {
return new NodeStateEvent(null, NodeState.UNKNOWN, node);
}
public static NodeStateEvent removed(DefaultNode node) {
return new NodeStateEvent(null, null, node);
}
/** The state before the change, or {@code null} if this is an addition or a removal. */
public final NodeState oldState;
/**
* The state after the change ({@link NodeState#UNKNOWN} if the node was just added), or {@code
* null} if this is a removal.
*/
public final NodeState newState;
public final DefaultNode node;
private NodeStateEvent(NodeState oldState, NodeState newState, DefaultNode node) {
this.node = node;
this.oldState = oldState;
this.newState = newState;
}
@Override
public boolean equals(Object other) {
if (other == this) {
return true;
} else if (other instanceof NodeStateEvent) {
NodeStateEvent that = (NodeStateEvent) other;
return this.oldState == that.oldState
&& this.newState == that.newState
&& Objects.equals(this.node, that.node);
} else {
return false;
}
}
@Override
public int hashCode() {
return Objects.hash(oldState, newState, node);
}
@Override
public String toString() {
return "NodeStateEvent(" + oldState + "=>" + newState + ", " + node + ")";
}
}