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/**
* 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 org.apache.curator.framework.recipes.atomic;
public interface DistributedAtomicNumber
{
/**
* Returns the current value of the counter. NOTE: if the value has never been set,
* 0
is returned.
*
* @return value info
* @throws Exception ZooKeeper errors
*/
public AtomicValue get() throws Exception;
/**
* Atomically sets the value to the given updated value
* if the current value {@code ==} the expected value.
* Remember to always check {@link AtomicValue#succeeded()}.
*
* @param expectedValue the expected value
* @param newValue the new value for the counter
* @return value info
* @throws Exception ZooKeeper errors
*/
public AtomicValue compareAndSet(T expectedValue, T newValue) throws Exception;
/**
* Attempt to atomically set the value to the given value. Remember to always
* check {@link AtomicValue#succeeded()}.
*
* @param newValue the value to set
* @return value info
* @throws Exception ZooKeeper errors
*/
public AtomicValue trySet(T newValue) throws Exception;
/**
* Atomic values are initially set to the equivalent of NULL
in a database.
* Use this method to initialize the value. The value will be set if and only iff the node does not exist.
*
* @param value the initial value to set
* @return true if the value was set, false if the node already existed
* @throws Exception ZooKeeper errors
*/
public boolean initialize(T value) throws Exception;
/**
* Forcibly sets the value of the counter without any guarantees of atomicity.
*
* @param newValue the new value
* @throws Exception ZooKeeper errors
*/
public void forceSet(T newValue) throws Exception;
/**
* Add 1 to the current value and return the new value information. Remember to always
* check {@link AtomicValue#succeeded()}.
*
* @return value info
* @throws Exception ZooKeeper errors
*/
public AtomicValue increment() throws Exception;
/**
* Subtract 1 from the current value and return the new value information. Remember to always
* check {@link AtomicValue#succeeded()}.
*
* @return value info
* @throws Exception ZooKeeper errors
*/
public AtomicValue decrement() throws Exception;
/**
* Add delta to the current value and return the new value information. Remember to always
* check {@link AtomicValue#succeeded()}.
*
* @param delta amount to add
* @return value info
* @throws Exception ZooKeeper errors
*/
public AtomicValue add(T delta) throws Exception;
/**
* Subtract delta from the current value and return the new value information. Remember to always
* check {@link AtomicValue#succeeded()}.
*
* @param delta amount to subtract
* @return value info
* @throws Exception ZooKeeper errors
*/
public AtomicValue subtract(T delta) throws Exception;
}