org.elasticsearch.cluster.routing.allocation.decider.Decision Maven / Gradle / Ivy
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* 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
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* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.cluster.routing.allocation.decider;
import com.google.common.collect.Lists;
import java.util.List;
import java.util.Locale;
/**
* This abstract class defining basic {@link Decision} used during shard
* allocation process.
*
* @see AllocationDecider
*/
public abstract class Decision {
public static final Decision ALWAYS = new Single(Type.YES);
public static final Decision YES = new Single(Type.YES);
public static final Decision NO = new Single(Type.NO);
public static final Decision THROTTLE = new Single(Type.THROTTLE);
/**
* Creates a simple decision
* @param type {@link Type} of the decision
* @param explanation explanation of the decision
* @param explanationParams additional parameters for the decision
* @return new {@link Decision} instance
*/
public static Decision single(Type type, String explanation, Object... explanationParams) {
return new Single(type, explanation, explanationParams);
}
/**
* This enumeration defines the
* possible types of decisions
*/
public static enum Type {
YES,
NO,
THROTTLE
}
/**
* Get the {@link Type} of this decision
* @return {@link Type} of this decision
*/
public abstract Type type();
/**
* Simple class representing a single decision
*/
public static class Single extends Decision {
private final Type type;
private final String explanation;
private final Object[] explanationParams;
/**
* Creates a new {@link Single} decision of a given type
* @param type {@link Type} of the decision
*/
public Single(Type type) {
this(type, null, (Object[]) null);
}
/**
* Creates a new {@link Single} decision of a given type
*
* @param type {@link Type} of the decision
* @param explanation An explanation of this {@link Decision}
* @param explanationParams A set of additional parameters
*/
public Single(Type type, String explanation, Object... explanationParams) {
this.type = type;
this.explanation = explanation;
this.explanationParams = explanationParams;
}
@Override
public Type type() {
return this.type;
}
@Override
public String toString() {
if (explanation == null) {
return type + "()";
}
return type + "(" + String.format(Locale.ROOT, explanation, explanationParams) + ")";
}
}
/**
* Simple class representing a list of decisions
*/
public static class Multi extends Decision {
private final List decisions = Lists.newArrayList();
/**
* Add a decission to this {@link Multi}decision instance
* @param decision {@link Decision} to add
* @return {@link Multi}decision instance with the given decision added
*/
public Multi add(Decision decision) {
decisions.add(decision);
return this;
}
@Override
public Type type() {
Type ret = Type.YES;
for (int i = 0; i < decisions.size(); i++) {
Type type = decisions.get(i).type();
if (type == Type.NO) {
return type;
} else if (type == Type.THROTTLE) {
ret = type;
}
}
return ret;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
for (Decision decision : decisions) {
sb.append("[").append(decision.toString()).append("]");
}
return sb.toString();
}
}
}