RedisCacheKey.java

/*
 * Copyright 2014 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.data.redis.cache;

import static org.springframework.util.Assert.*;

import java.util.Arrays;

import org.springframework.data.redis.serializer.RedisSerializer;

/**
 * @author Christoph Strobl
 * @since 1.5
 */
public class RedisCacheKey {

	private final Object keyElement;
	private byte[] prefix;
	@SuppressWarnings("rawtypes")//
	private RedisSerializer serializer;

	/**
	 * @param keyElement must not be {@literal null}.
	 */
	public RedisCacheKey(Object keyElement) {

		notNull(keyElement, "KeyElement must not be null!");
		this.keyElement = keyElement;
	}

	/**
	 * Get the {@link Byte} representation of the given key element using prefix if available.
	 */
	public byte[] getKeyBytes() {

		byte[] rawKey = serializeKeyElement();
		if (!hasPrefix()) {
			return rawKey;
		}

		byte[] prefixedKey = Arrays.copyOf(prefix, prefix.length + rawKey.length);
		System.arraycopy(rawKey, 0, prefixedKey, prefix.length, rawKey.length);

		return prefixedKey;
	}

	/**
	 * @return
	 */
	public Object getKeyElement() {
		return keyElement;
	}

	@SuppressWarnings("unchecked")
	private byte[] serializeKeyElement() {

		if (serializer == null && keyElement instanceof byte[]) {
			return (byte[]) keyElement;
		}

		return serializer.serialize(keyElement);
	}

	/**
	 * Set the {@link RedisSerializer} used for converting the key into its {@link Byte} representation.
	 * 
	 * @param serializer can be {@literal null}.
	 */
	public void setSerializer(RedisSerializer<?> serializer) {
		this.serializer = serializer;
	}

	/**
	 * @return true if prefix is not empty.
	 */
	public boolean hasPrefix() {
		return (prefix != null && prefix.length > 0);
	}

	/**
	 * Use the given prefix when generating key.
	 * 
	 * @param prefix can be {@literal null}.
	 * @return
	 */
	public RedisCacheKey usePrefix(byte[] prefix) {
		this.prefix = prefix;
		return this;
	}

	/**
	 * Use {@link RedisSerializer} for converting the key into its {@link Byte} representation.
	 * 
	 * @param serializer can be {@literal null}.
	 * @return
	 */
	public RedisCacheKey withKeySerializer(RedisSerializer serializer) {

		this.serializer = serializer;
		return this;
	}

}