ChannelsEndpoint to show all the binding properties

- Set the default destination name when it is not explicitly set
 - The producer/consumer properties would also be shown via BindingProperties
  - Handle JSON serialization when the value is of type Expression

This resolves #406 #426

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/binder/ExpressionSerializer.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2016 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.cloud.stream.binder;
+
+import java.io.IOException;
+
+import org.springframework.expression.Expression;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+
+/**
+ * JSON serializer for Expression value.
+ *
+ * @author Ilayaperumal Gopinathan
+ */
+public class ExpressionSerializer extends JsonSerializer<Expression> {
+
+	public ExpressionSerializer() {
+	}
+
+	@Override
+	public void serialize(Expression expression, JsonGenerator jsonGenerator, SerializerProvider serializerProvider)
+			throws IOException {
+		if (expression != null) {
+			jsonGenerator.writeString(expression.getExpressionString());
+		}
+	}
+}

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/binder/ProducerProperties.java

@@ -18,6 +18,8 @@ package org.springframework.cloud.stream.binder;
 
 import org.springframework.expression.Expression;
 
+import com.fasterxml.jackson.databind.annotation.JsonSerialize;
+
 /**
  * Common producer properties.
  *
@@ -25,12 +27,14 @@ import org.springframework.expression.Expression;
  */
 public class ProducerProperties {
 
+	@JsonSerialize(using = ExpressionSerializer.class)
 	private Expression partitionKeyExpression = null;
 
 	private Class<?> partitionKeyExtractorClass = null;
 
 	private Class<?> partitionSelectorClass = null;
 
+	@JsonSerialize(using = ExpressionSerializer.class)
 	private Expression partitionSelectorExpression = null;
 
 	private int partitionCount = 1;

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/binding/DynamicDestinationsBindable.java

@@ -32,7 +32,7 @@ import org.springframework.cloud.stream.binder.Binding;
 public final class DynamicDestinationsBindable extends BindableAdapter {
 
 	/**
-	 * Map containing dynamic destination names and their bindings.
+	 * Map containing channel names and their bindings.
 	 */
 	private Map<String, Binding> outputBindings = new HashMap<>();
 

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/config/BindingProperties.java

@@ -18,13 +18,13 @@ package org.springframework.cloud.stream.config;
 
 import javax.validation.constraints.AssertTrue;
 
-import com.fasterxml.jackson.annotation.JsonInclude;
-import com.fasterxml.jackson.annotation.JsonInclude.Include;
-
 import org.springframework.cloud.stream.binder.ConsumerProperties;
 import org.springframework.cloud.stream.binder.ProducerProperties;
 import org.springframework.validation.annotation.Validated;
 
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonInclude.Include;
+
 /**
  * Contains the properties of a binding.
  * @author Marius Bogoevici
@@ -56,7 +56,6 @@ public class BindingProperties {
 
 	private String binder;
 
-
 	private ConsumerProperties consumer = null;
 
 	private ProducerProperties producer = null;

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/config/ChannelBindingServiceProperties.java

@@ -21,9 +21,7 @@ import java.util.Map;
 import java.util.Properties;
 import java.util.TreeMap;
 
-import com.fasterxml.jackson.annotation.JsonInclude;
-import com.fasterxml.jackson.annotation.JsonInclude.Include;
-
+import org.springframework.beans.BeanUtils;
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.beans.factory.annotation.Value;
@@ -36,7 +34,9 @@ import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.integration.support.utils.IntegrationUtils;
 import org.springframework.util.Assert;
-import org.springframework.util.StringUtils;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonInclude.Include;
 
 /**
  * @author Dave Syer
@@ -189,7 +189,6 @@ public class ChannelBindingServiceProperties implements ApplicationContextAware,
 		return consumerProperties;
 	}
 
-
 	public ProducerProperties getProducerProperties(String outputChannelName) {
 		Assert.notNull(outputChannelName, "The output channel name cannot be null");
 		ProducerProperties producerProperties = getBindingProperties(outputChannelName).getProducer();
@@ -200,8 +199,13 @@ public class ChannelBindingServiceProperties implements ApplicationContextAware,
 	}
 
 	public BindingProperties getBindingProperties(String channelName) {
-		BindingProperties bindingProperties = bindings.containsKey(channelName) ?
-				bindings.get(channelName) : new BindingProperties();
+		BindingProperties bindingProperties = new BindingProperties();
+		if (this.bindings.containsKey(channelName)) {
+			BeanUtils.copyProperties(this.bindings.get(channelName), bindingProperties);
+		}
+		if (bindingProperties.getDestination() == null) {
+			bindingProperties.setDestination(channelName);
+		}
 		return bindingProperties;
 	}
 
@@ -210,10 +214,6 @@ public class ChannelBindingServiceProperties implements ApplicationContextAware,
 	}
 
 	public String getBindingDestination(String channelName) {
-		BindingProperties bindingProperties = getBindingProperties(channelName);
-		if (bindingProperties != null && StringUtils.hasText(bindingProperties.getDestination())) {
-			return bindingProperties.getDestination();
-		}
-		return channelName;
+		return getBindingProperties(channelName).getDestination();
 	}
 }

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/endpoint/ChannelsEndpoint.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 the original author or authors.
+ * Copyright 2015-2016 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.
@@ -20,49 +20,49 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.springframework.boot.actuate.endpoint.AbstractEndpoint;
+import org.springframework.boot.actuate.endpoint.Endpoint;
+import org.springframework.cloud.stream.binding.Bindable;
+import org.springframework.cloud.stream.config.BindingProperties;
+import org.springframework.cloud.stream.config.ChannelBindingServiceProperties;
+
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.ObjectMapper;
 
-import org.springframework.boot.actuate.endpoint.AbstractEndpoint;
-import org.springframework.cloud.stream.binding.Bindable;
-import org.springframework.cloud.stream.config.BindingProperties;
-import org.springframework.cloud.stream.config.ChannelBindingServiceProperties;
-
 /**
+ * An {@link Endpoint} that has the binding information on all the {@link Bindable} message channels.
+ *
  * @author Dave Syer
+ * @author Ilayaperumal Gopinathan
  */
-public class ChannelsEndpoint extends AbstractEndpoint<Map<String,Object>> {
+public class ChannelsEndpoint extends AbstractEndpoint<Map<String, Object>> {
 
 	private List<Bindable> adapters;
 
 	private ChannelBindingServiceProperties properties;
 
-	public ChannelsEndpoint(List<Bindable> adapters,
-			ChannelBindingServiceProperties properties) {
+	public ChannelsEndpoint(List<Bindable> adapters, ChannelBindingServiceProperties properties) {
 		super("channels");
 		this.adapters = adapters;
 		this.properties = properties;
 	}
 
 	@Override
-	public Map<String,Object> invoke() {
+	public Map<String, Object> invoke() {
 		ChannelsMetaData map = new ChannelsMetaData();
 		Map<String, BindingProperties> inputs = map.getInputs();
 		Map<String, BindingProperties> outputs = map.getOutputs();
 		for (Bindable factory : this.adapters) {
-			Map<String, BindingProperties> bindings = this.properties.getBindings();
 			for (String name : factory.getInputs()) {
-				inputs.put(name, bindings.containsKey(name) ? bindings.get(name)
-						: new BindingProperties());
+				inputs.put(name, this.properties.getBindingProperties(name));
 			}
 			for (String name : factory.getOutputs()) {
-				outputs.put(name, bindings.containsKey(name) ? bindings.get(name)
-						: new BindingProperties());
+				outputs.put(name, this.properties.getBindingProperties(name));
 			}
 		}
-		return new ObjectMapper().convertValue(map, new TypeReference<Map<String,Object>>() {
+		return new ObjectMapper().convertValue(map, new TypeReference<Map<String, Object>>() {
 		});
 	}
 
@@ -77,17 +77,9 @@ public class ChannelsEndpoint extends AbstractEndpoint<Map<String,Object>> {
 			return this.inputs;
 		}
 
-		public void setInputs(Map<String, BindingProperties> inputs) {
-			this.inputs = inputs;
-		}
-
 		public Map<String, BindingProperties> getOutputs() {
 			return this.outputs;
 		}
-
-		public void setOutputs(Map<String, BindingProperties> outputs) {
-			this.outputs = outputs;
-		}
 	}
 
 }