Support exchange-to-exchange binding and unbinding

Fixes #121

Author: acogoluegnes

src/docs/asciidoc/new.adoc

@@ -2,6 +2,10 @@
 
 [[new]]
 
+=== What's new in Reactor RabbitMQ 1.4.1
+
+* Support exchange-to-exchange binding and unbinding
+
 === What's new in Reactor RabbitMQ 1.4
 
 * Add `@NonNullApi` and `@Nullable` annotations

src/main/java/reactor/rabbitmq/BindingSpecification.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017 Pivotal Software Inc, All Rights Reserved.
+ * Copyright (c) 2017-2019 Pivotal Software Inc, All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,36 +21,137 @@
 import java.util.Map;
 
 /**
- * Fluent API to specify the binding between an exchange and a queue.
+ * Fluent API to specify the binding between AMQP resources.
+ * Support exchange-to-queue and exchange-to-exchange binding definition.
  */
 public class BindingSpecification {
 
-    private String queue, exchange, routingKey;
+    private String queue, exchange, exchangeTo, routingKey;
     private Map<String, Object> arguments;
 
     public static BindingSpecification binding() {
         return new BindingSpecification();
     }
 
+    /**
+     * Create an exchange-to-queue binding specification.
+     *
+     * @param exchange
+     * @param routingKey
+     * @param queue
+     * @return
+     */
     public static BindingSpecification binding(String exchange, String routingKey, String queue) {
         return new BindingSpecification().exchange(exchange).routingKey(routingKey).queue(queue);
     }
 
+    /**
+     * Create an exchange-to-queue binding specification.
+     *
+     * @param exchange
+     * @param routingKey
+     * @param queue
+     * @return
+     * @since 1.4.1
+     */
+    public static BindingSpecification queueBinding(String exchange, String routingKey, String queue) {
+        return binding(exchange, routingKey, queue);
+    }
+
+    /**
+     * Creates an exchange-to-exchange binding specification.
+     *
+     * @param exchangeFrom
+     * @param routingKey
+     * @param exchangeTo
+     * @return
+     * @since 1.4.1
+     */
+    public static BindingSpecification exchangeBinding(String exchangeFrom, String routingKey, String exchangeTo) {
+        return new BindingSpecification().exchangeFrom(exchangeFrom).routingKey(routingKey).exchangeTo(exchangeTo);
+    }
+
+    /**
+     * The queue to bind to.
+     * <p>
+     * Use this method for exchange-to-queue binding or
+     * {@link #exchangeTo(String)} for exchange-to-exchange, but not both.
+     *
+     * @param queue
+     * @return
+     */
     public BindingSpecification queue(String queue) {
         this.queue = queue;
         return this;
     }
 
+    /**
+     * The exchange to bind from.
+     * <p>
+     * Alias of {@link #exchangeFrom(String)}. Usually used for
+     * exchange-to-queue binding, but can be used for exchange-to-exchange
+     * binding as well.
+     *
+     * @param exchange
+     * @return
+     * @see #exchangeFrom(String)
+     * @see #exchangeTo(String)
+     */
     public BindingSpecification exchange(String exchange) {
         this.exchange = exchange;
         return this;
     }
 
+    /**
+     * The exchange to bind from.
+     * <p>
+     * Alias of {@link #exchange(String)}. Usually used to make explicit
+     * the definition is for an exchange-to-exchange binding, but works for
+     * exchange-to-queue binding as well.
+     *
+     * @param exchangeFrom
+     * @return
+     * @see #exchange(String)
+     * @see #exchangeTo(String)
+     * @since 1.4.1
+     */
+    public BindingSpecification exchangeFrom(String exchangeFrom) {
+        this.exchange = exchangeFrom;
+        return this;
+    }
+
+    /**
+     * The exchange to bind to.
+     * <p>
+     * Use this method for exchange-to-exchange binding or
+     * {@link #queue(String)} for exchange-to-queue binding, but not both.
+     *
+     * @param exchangeTo
+     * @return
+     * @since 1.4.1
+     */
+    public BindingSpecification exchangeTo(String exchangeTo) {
+        this.exchangeTo = exchangeTo;
+        return this;
+    }
+
+    /**
+     * The routing key for the binding.
+     *
+     * @param routingKey
+     * @return
+     */
     public BindingSpecification routingKey(String routingKey) {
         this.routingKey = routingKey;
         return this;
     }
 
+    /**
+     * Arguments of the binding. These are optional.
+     *
+     * @param arguments
+     * @return
+     */
     public BindingSpecification arguments(@Nullable Map<String, Object> arguments) {
         this.arguments = arguments;
         return this;
@@ -68,6 +169,10 @@ public String getRoutingKey() {
         return routingKey;
     }
 
+    public String getExchangeTo() {
+        return exchangeTo;
+    }
+
     @Nullable
     public Map<String, Object> getArguments() {
         return arguments;