Remove unused ThreadLocal from RedisStoreMSource (#8663)

* Remove unused ThreadLocal from RedisStoreMSource

The `RedisStoreMessageSource` relies on an `IntegrationResourceHolder`
for a while already.
Its internal `ThreadLocal` is just out of use.

* Remove that `resourceHolder` property and related methods to interact with it.
* Mention the `IntegrationResourceHolder` and `store` attribute in the `redis.adoc`

* Fix language in Docs

Co-authored-by: Gary Russell <[email protected]>

---------

Co-authored-by: Gary Russell <[email protected]>

Author: artembilan

spring-integration-redis/src/main/java/org/springframework/integration/redis/inbound/RedisStoreMessageSource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -46,18 +46,16 @@
  */
 public class RedisStoreMessageSource extends AbstractMessageSource<RedisStore> {
 
-	private final ThreadLocal<RedisStore> resourceHolder = new ThreadLocal<>();
-
-	private volatile StandardEvaluationContext evaluationContext;
+	private final RedisTemplate<String, ?> redisTemplate;
 
-	private volatile Expression keyExpression;
+	private final Expression keyExpression;
 
-	private volatile CollectionType collectionType = CollectionType.LIST;
+	private StandardEvaluationContext evaluationContext;
 
-	private final RedisTemplate<String, ?> redisTemplate;
+	private CollectionType collectionType = CollectionType.LIST;
 
 	/**
-	 * Creates an instance with the provided {@link RedisTemplate} and SpEL expression
+	 * Create an instance with the provided {@link RedisTemplate} and SpEL expression
 	 * which should resolve to a 'key' name of the collection to be used.
 	 * It assumes that {@link RedisTemplate} is fully initialized and ready to be used.
 	 * The 'keyExpression' will be evaluated on every call to the {@link #receive()} method.
@@ -73,7 +71,7 @@ public RedisStoreMessageSource(RedisTemplate<String, ?> redisTemplate, Expressio
 	}
 
 	/**
-	 * Creates an instance with the provided {@link RedisConnectionFactory} and SpEL expression
+	 * Create an instance with the provided {@link RedisConnectionFactory} and SpEL expression
 	 * which should resolve to a 'key' name of the collection to be used.
 	 * It will create and initialize an instance of {@link StringRedisTemplate} that uses
 	 * {@link org.springframework.data.redis.serializer.StringRedisSerializer} for all
@@ -82,9 +80,7 @@ public RedisStoreMessageSource(RedisTemplate<String, ?> redisTemplate, Expressio
 	 * @param connectionFactory The connection factory.
 	 * @param keyExpression The key expression.
 	 */
-	public RedisStoreMessageSource(RedisConnectionFactory connectionFactory,
-			Expression keyExpression) {
-
+	public RedisStoreMessageSource(RedisConnectionFactory connectionFactory, Expression keyExpression) {
 		Assert.notNull(keyExpression, "'keyExpression' must not be null");
 		Assert.notNull(connectionFactory, "'connectionFactory' must not be null");
 
@@ -105,15 +101,15 @@ protected void onInit() {
 	}
 
 	/**
-	 * Returns a Message with the view into a {@link RedisStore} identified
+	 * Return a Message with the view into a {@link RedisStore} identified
 	 * by {@link #keyExpression}
 	 */
 	@Override
 	protected RedisStore doReceive() {
 		String key = this.keyExpression.getValue(this.evaluationContext, String.class);
 		Assert.hasText(key, "Failed to determine the key for the collection");
 
-		RedisStore store = this.createStoreView(key);
+		RedisStore store = createStoreView(key);
 
 		Object holder = TransactionSynchronizationManager.getResource(this);
 		if (holder != null) {
@@ -143,16 +139,4 @@ public String getComponentType() {
 		return "redis:store-inbound-channel-adapter";
 	}
 
-	public RedisStore getResource() {
-		return this.resourceHolder.get();
-	}
-
-	public void afterCommit(Object object) {
-		this.resourceHolder.remove();
-	}
-
-	public void afterRollback(Object object) {
-		this.resourceHolder.remove();
-	}
-
 }

src/reference/asciidoc/redis.adoc

@@ -558,6 +558,8 @@ If only the `expression` attribute is present and the result of an expression is
 If you want the evaluation result to go to a specific channel, add a `channel` attribute.
 If the result of an expression is null or void, no message is generated.
 
+The `RedisStoreMessageSource` adds a `store` attribute with a `RedisStore` instance bound to the transaction `IntegrationResourceHolder`, which can be accessed from a `TransactionSynchronizationProcessor` implementation.
+
 For more information about transaction synchronization, see <<./transactions.adoc#transaction-synchronization,Transaction Synchronization>>.
 
 [[redis-store-outbound-channel-adapter]]
@@ -895,4 +897,4 @@ Default.
 - `RedisLockType.PUB_SUB_LOCK` - The lock is acquired by redis pub-sub subscription.
 
 The pub-sub is preferred mode - less network chatter between client Redis server, and more performant - the lock is acquired immediately when subscription is notified about unlocking in the other process.
-However, the Redis does not support pub-sub in the Master/Replica connections (for example in AWS ElastiCache environment), therefore a busy-spin mode is chosen as a default to make the registry working in any environment.
+However, the Redis does not support pub-sub in the Master/Replica connections (for example in AWS ElastiCache environment), therefore a busy-spin mode is chosen as a default to make the registry working in any environment.