+ add RedisAtomicLong

spring-datastore-redis/src/main/java/org/springframework/datastore/redis/util/RedisAtomicLong.java

@@ -0,0 +1,213 @@
+/*
+ * Copyright 2006-2009 the original author or authors.
+ * 
+ * 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.springframework.datastore.redis.util;
+
+import java.io.Serializable;
+
+import org.springframework.datastore.redis.connection.RedisCommands;
+
+/**
+ * Atomic long backed by Redis.
+ * Uses Redis atomic increment/decrement and watch/multi/exec commands for CAS operations.
+ *  
+ * @see java.util.concurrent.atomic.AtomicLong
+ * @author Costin Leau
+ */
+public class RedisAtomicLong extends Number implements Serializable {
+
+	private final String key;
+	private RedisCommands commands;
+
+	/**
+	 * Constructs a new <code>RedisAtomicLong</code> instance with an initial value of zero.
+	 *
+	 * @param redisCounter
+	 * @param commands
+	 */
+	public RedisAtomicLong(String redisCounter, RedisCommands commands) {
+		this(redisCounter, commands, 0);
+	}
+
+	/**
+	 * Constructs a new <code>RedisAtomicLong</code> instance with the given initial value.
+	 *
+	 * @param redisCounter
+	 * @param commands
+	 * @param initialValue
+	 */
+	public RedisAtomicLong(String redisCounter, RedisCommands commands, long initialValue) {
+		this.key = redisCounter;
+		this.commands = commands;
+		commands.set(redisCounter, Long.toString(initialValue));
+	}
+
+	/**
+	 * Gets the current value.
+	 *
+	 * @return the current value
+	 */
+	public long get() {
+		return Long.valueOf(commands.get(key));
+	}
+
+	/**
+	 * Sets to the given value.
+	 *
+	 * @param newValue the new value
+	 */
+	public void set(long newValue) {
+		commands.set(key, Long.toString(newValue));
+	}
+
+	/**
+	 * Atomically sets to the given value and returns the old value.
+	 *
+	 * @param newValue the new value
+	 * @return the previous value
+	 */
+	public long getAndSet(long newValue) {
+		return Long.valueOf(commands.getSet(key, Long.toString(newValue)));
+	}
+
+	/**
+	 * Atomically sets the value to the given updated value
+	 * if the current value {@code ==} the expected value.
+	 *
+	 * @param expect the expected value
+	 * @param update the new value
+	 * @return true if successful. False return indicates that
+	 * the actual value was not equal to the expected value.
+	 */
+	public boolean compareAndSet(long expect, long update) {
+		for (;;) {
+			commands.watch(key);
+			if (expect == get()) {
+				commands.multi();
+				set(update);
+				if (commands.exec() != null) {
+					return true;
+				}
+			}
+			return false;
+		}
+	}
+
+	/**
+	 * Atomically increments by one the current value.
+	 *
+	 * @return the previous value
+	 */
+	public long getAndIncrement() {
+		for (;;) {
+			commands.watch(key);
+			long value = get();
+			commands.multi();
+			commands.incr(key);
+			if (commands.exec() != null) {
+				return value;
+			}
+		}
+	}
+
+	/**
+	 * Atomically decrements by one the current value.
+	 *
+	 * @return the previous value
+	 */
+	public long getAndDecrement() {
+		for (;;) {
+			commands.watch(key);
+			long value = get();
+			commands.multi();
+			commands.decr(key);
+			if (commands.exec() != null) {
+				return value;
+			}
+		}
+	}
+
+	/**
+	 * Atomically adds the given value to the current value.
+	 *
+	 * @param delta the value to add
+	 * @return the previous value
+	 */
+	public long getAndAdd(long delta) {
+		for (;;) {
+			commands.watch(key);
+			long value = get();
+			commands.multi();
+			set(value + delta);
+			if (commands.exec() != null) {
+				return value;
+			}
+		}
+	}
+
+	/**
+	 * Atomically increments by one the current value.
+	 *
+	 * @return the updated value
+	 */
+	public long incrementAndGet() {
+		return commands.incr(key);
+	}
+
+	/**
+	 * Atomically decrements by one the current value.
+	 *
+	 * @return the updated value
+	 */
+	public long decrementAndGet() {
+		return commands.decr(key);
+	}
+
+	/**
+	 * Atomically adds the given value to the current value.
+	 *
+	 * @param delta the value to add
+	 * @return the updated value
+	 */
+	public long addAndGet(long delta) {
+		// TODO: is this really safe
+		return commands.incrBy(key, (int) delta);
+	}
+
+	/**
+	 * Returns the String representation of the current value.
+	 * @return the String representation of the current value.
+	 */
+	public String toString() {
+		return Long.toString(get());
+	}
+
+
+	public int intValue() {
+		return (int) get();
+	}
+
+	public long longValue() {
+		return (long) get();
+	}
+
+	public float floatValue() {
+		return (float) get();
+	}
+
+	public double doubleValue() {
+		return (double) get();
+	}
+}