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/*
* Copyright 2015 Open Networking Laboratory
*
* 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 org.onosproject.store.consistent.impl;
import static com.google.common.base.MoreObjects.toStringHelper;
import java.util.Objects;
/**
* Result of a database update operation.
*
* @param <V> return value type
*/
public final class Result<V> {
public enum Status {
/**
* Indicates a successful update.
*/
OK,
/**
* Indicates a failure due to underlying state being locked by another transaction.
*/
LOCKED
}
private final Status status;
private final V value;
/**
* Creates a new Result instance with the specified value with status set to Status.OK.
*
* @param <V> result value type
* @param value result value
* @return Result instance
*/
public static <V> Result<V> ok(V value) {
return new Result<>(value, Status.OK);
}
/**
* Creates a new Result instance with status set to Status.LOCKED.
*
* @param <V> result value type
* @return Result instance
*/
public static <V> Result<V> locked() {
return new Result<>(null, Status.LOCKED);
}
private Result(V value, Status status) {
this.value = value;
this.status = status;
}
/**
* Returns true if this result indicates a successful execution i.e status is Status.OK.
*
* @return true if successful, false otherwise
*/
public boolean success() {
return status == Status.OK;
}
/**
* Returns the status of database update operation.
*
* @return database update status
*/
public Status status() {
return status;
}
/**
* Returns the return value for the update.
*
* @return value returned by database update. If the status is another
* other than Status.OK, this returns a null
*/
public V value() {
return value;
}
@Override
public int hashCode() {
return Objects.hash(value, status);
}
@SuppressWarnings("unchecked")
@Override
public boolean equals(Object other) {
if (!(other instanceof Result)) {
return false;
}
Result<V> that = (Result<V>) other;
return Objects.equals(this.value, that.value) &&
Objects.equals(this.status, that.status);
}
@Override
public String toString() {
return toStringHelper(this)
.add("status", status)
.add("value", value)
.toString();
}
}
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