DSL: Add enrichHeaders(Map) EIP-method

* Introduce `MapBuilder` and its custom inheritor - `MailHeadersBuilder`
* Add `HeaderEnricherSpec.headers(MapBuilder)` and `.headers(Map)`
* Change `MailTests` to use new `Mail.headers()` and new `IntegrationFlowDefinition.enrichHeaders(MapBuilder)`
* Change `mailapi` dependency to the IO's `javax.mail`

Polishing - Add headerExpressions()

More Polishing - Add Configurer

Polishing - PR Comments

- Move MapBuilderConfigurer to superclass.
- Move PropertiesBuilderConfigurer into PropertiesBuilder.

spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/HeaderEnricherSpec.java

@@ -18,11 +18,16 @@ package org.springframework.integration.dsl;
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Map.Entry;
 
+import org.springframework.expression.Expression;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.integration.context.IntegrationContextUtils;
 import org.springframework.integration.dsl.core.IntegrationComponentSpec;
 import org.springframework.integration.dsl.support.BeanNameMessageProcessor;
+import org.springframework.integration.dsl.support.MapBuilder;
+import org.springframework.integration.dsl.support.MapBuilder.MapBuilderConfigurer;
+import org.springframework.integration.dsl.support.StringStringMapBuilder;
 import org.springframework.integration.handler.ExpressionEvaluatingMessageProcessor;
 import org.springframework.integration.handler.MessageProcessor;
 import org.springframework.integration.transformer.HeaderEnricher;
@@ -34,6 +39,7 @@ import org.springframework.util.Assert;
 
 /**
  * @author Artem Bilan
+ * @author Gary Russell
  */
 public class HeaderEnricherSpec extends IntegrationComponentSpec<HeaderEnricherSpec, HeaderEnricher> {
 
@@ -70,6 +76,43 @@ public class HeaderEnricherSpec extends IntegrationComponentSpec<HeaderEnricherS
 		return this.messageProcessor(new BeanNameMessageProcessor<Object>(beanName, methodName));
 	}
 
+	public HeaderEnricherSpec headers(MapBuilder<?, String, Object> headers) {
+		return headers(headers.get());
+	}
+
+	public HeaderEnricherSpec headers(Map<String, Object> headers) {
+		Assert.notNull(headers);
+		for (Entry<String, Object> entry : headers.entrySet()) {
+			String name = entry.getKey();
+			Object value = entry.getValue();
+			if (value instanceof Expression) {
+				header(name, new ExpressionEvaluatingHeaderValueMessageProcessor<Object>((Expression) value, null));
+			}
+			else {
+				header(name, value);
+			}
+		}
+		return this;
+	}
+
+	public HeaderEnricherSpec headerExpressions(MapBuilder<?, String, String> headers) {
+		return headerExpressions(headers.get());
+	}
+
+	public HeaderEnricherSpec headerExpressions(MapBuilderConfigurer<StringStringMapBuilder, String, String> configurer) {
+		StringStringMapBuilder builder = new StringStringMapBuilder();
+		configurer.configure(builder);
+		return headerExpressions(builder.get());
+	}
+
+	public HeaderEnricherSpec headerExpressions(Map<String, String> headers) {
+		Assert.notNull(headers);
+		for (Entry<String, String> entry : headers.entrySet()) {
+			header(entry.getKey(), new ExpressionEvaluatingHeaderValueMessageProcessor<Object>(entry.getValue(), null));
+		}
+		return this;
+	}
+
 	public <V> HeaderEnricherSpec header(String name, V value) {
 		return this.header(name, value, null);
 	}

spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/IntegrationFlowDefinition.java

@@ -18,6 +18,7 @@ package org.springframework.integration.dsl;
 
 import java.util.Collection;
 import java.util.LinkedHashSet;
+import java.util.Map;
 import java.util.Set;
 
 import org.springframework.beans.factory.BeanCreationException;
@@ -40,6 +41,7 @@ import org.springframework.integration.dsl.support.FixedSubscriberChannelPrototy
 import org.springframework.integration.dsl.support.GenericHandler;
 import org.springframework.integration.dsl.support.GenericRouter;
 import org.springframework.integration.dsl.support.GenericSplitter;
+import org.springframework.integration.dsl.support.MapBuilder;
 import org.springframework.integration.dsl.support.MessageChannelReference;
 import org.springframework.integration.expression.ControlBusMethodFilter;
 import org.springframework.integration.filter.ExpressionEvaluatingSelector;
@@ -76,6 +78,7 @@ import org.springframework.util.StringUtils;
 
 /**
  * @author Artem Bilan
+ * @author Gary Russell
  */
 public abstract class IntegrationFlowDefinition<B extends IntegrationFlowDefinition<B>> {
 
@@ -286,6 +289,37 @@ public abstract class IntegrationFlowDefinition<B extends IntegrationFlowDefinit
 		return this.handle(enricherSpec.get(), endpointConfigurer);
 	}
 
+	public B enrichHeaders(MapBuilder<?, String, Object> headers) {
+		return enrichHeaders(headers, null);
+	}
+
+	public B enrichHeaders(MapBuilder<?, String, Object> headers,
+			EndpointConfigurer<GenericEndpointSpec<MessageTransformingHandler>> endpointConfigurer) {
+		return enrichHeaders(headers.get(), endpointConfigurer);
+	}
+
+	/**
+	 * Accept a {@link Map} of values to be used for the
+	 * {@link org.springframework.messaging.Message} header enrichment.
+	 * {@code values} can apply an {@link org.springframework.expression.Expression}
+	 * to be evaluated against a request {@link org.springframework.messaging.Message}.
+	 * @param headers the Map of headers to enrich.
+	 * @return this.
+	 */
+	public B enrichHeaders(Map<String, Object> headers) {
+		return enrichHeaders(headers, null);
+	}
+
+	public B enrichHeaders(final Map<String, Object> headers,
+			EndpointConfigurer<GenericEndpointSpec<MessageTransformingHandler>> endpointConfigurer) {
+		return enrichHeaders(new ComponentConfigurer<HeaderEnricherSpec>() {
+			@Override
+			public void configure(HeaderEnricherSpec spec) {
+				spec.headers(headers);
+			}
+		}, endpointConfigurer);
+	}
+
 	public B enrichHeaders(ComponentConfigurer<HeaderEnricherSpec> headerEnricherConfigurer) {
 		return this.enrichHeaders(headerEnricherConfigurer, null);
 	}

spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/mail/ImapIdleChannelAdapterSpec.java

@@ -29,7 +29,7 @@ import org.aopalliance.aop.Advice;
 import org.springframework.integration.dsl.core.ComponentsRegistration;
 import org.springframework.integration.dsl.core.MessageProducerSpec;
 import org.springframework.integration.dsl.support.PropertiesBuilder;
-import org.springframework.integration.dsl.support.PropertiesConfigurer;
+import org.springframework.integration.dsl.support.PropertiesBuilder.PropertiesConfigurer;
 import org.springframework.integration.mail.ImapIdleChannelAdapter;
 import org.springframework.integration.mail.ImapMailReceiver;
 import org.springframework.integration.mail.SearchTermStrategy;

spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/mail/Mail.java

@@ -19,7 +19,7 @@ import org.springframework.integration.mail.ImapMailReceiver;
 
 /**
  * @author Gary Russell
- *
+ * @author Artem Bilan
  */
 public class Mail {
 
@@ -56,6 +56,10 @@ public class Mail {
 		return imapIdleAdapter(new ImapMailReceiver(url));
 	}
 
+	public static MailHeadersBuilder headers() {
+		return new MailHeadersBuilder();
+	}
+
 	private static ImapIdleChannelAdapterSpec imapIdleAdapter(ImapMailReceiver imapMailReceiver) {
 		return new ImapIdleChannelAdapterSpec(imapMailReceiver);
 	}

spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/mail/MailHeadersBuilder.java

@@ -0,0 +1,112 @@
+/*
+ * 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.integration.dsl.mail;
+
+import org.springframework.integration.dsl.support.MapBuilder;
+import org.springframework.integration.mail.MailHeaders;
+
+/**
+ * @author Artem Bilan
+ * @author Gary Russell
+ */
+public class MailHeadersBuilder extends MapBuilder<MailHeadersBuilder, String, Object> {
+
+	MailHeadersBuilder() {
+	}
+
+	public MailHeadersBuilder subject(String subject) {
+		return put(MailHeaders.SUBJECT, subject);
+	}
+
+	public MailHeadersBuilder subjectExpression(String subject) {
+		return putExpression(MailHeaders.SUBJECT, subject);
+	}
+
+	public MailHeadersBuilder to(String to) {
+		return put(MailHeaders.TO, to);
+	}
+
+	public MailHeadersBuilder toExpression(String to) {
+		return putExpression(MailHeaders.TO, to);
+	}
+
+	public MailHeadersBuilder cc(String cc) {
+		return put(MailHeaders.CC, cc);
+	}
+
+	public MailHeadersBuilder ccExpression(String cc) {
+		return putExpression(MailHeaders.CC, cc);
+	}
+
+	public MailHeadersBuilder bcc(String bcc) {
+		return put(MailHeaders.BCC, bcc);
+	}
+
+	public MailHeadersBuilder bccExpression(String bcc) {
+		return putExpression(MailHeaders.BCC, bcc);
+	}
+
+	public MailHeadersBuilder from(String from) {
+		return put(MailHeaders.FROM, from);
+	}
+
+	public MailHeadersBuilder fromExpression(String from) {
+		return putExpression(MailHeaders.FROM, from);
+	}
+
+	public MailHeadersBuilder replyTo(String replyTo) {
+		return put(MailHeaders.REPLY_TO, replyTo);
+	}
+
+	public MailHeadersBuilder replyToExpression(String replyTo) {
+		return putExpression(MailHeaders.REPLY_TO, replyTo);
+	}
+
+	/**
+	 * @param multipartMode header value
+	 * @return this
+	 * @see org.springframework.mail.javamail.MimeMessageHelper
+	 */
+	public MailHeadersBuilder multipartMode(int multipartMode) {
+		return put(MailHeaders.MULTIPART_MODE, multipartMode);
+	}
+
+	public MailHeadersBuilder multipartModeExpression(String multipartMode) {
+		return putExpression(MailHeaders.MULTIPART_MODE, multipartMode);
+	}
+
+	public MailHeadersBuilder attachmentFilename(String attachmentFilename) {
+		return put(MailHeaders.ATTACHMENT_FILENAME, attachmentFilename);
+	}
+
+	public MailHeadersBuilder attachmentFilenameExpression(String attachmentFilename) {
+		return putExpression(MailHeaders.ATTACHMENT_FILENAME, attachmentFilename);
+	}
+
+	public MailHeadersBuilder contentType(String contentType) {
+		return put(MailHeaders.CONTENT_TYPE, contentType);
+	}
+
+	public MailHeadersBuilder contentTypeExpression(String contentType) {
+		return putExpression(MailHeaders.CONTENT_TYPE, contentType);
+	}
+
+	private MailHeadersBuilder putExpression(String key, String expression) {
+		return put(key, PARSER.parseExpression(expression));
+	}
+
+}

spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/mail/MailInboundChannelAdapterSpec.java

@@ -25,7 +25,7 @@ import javax.mail.Session;
 import org.springframework.integration.dsl.core.ComponentsRegistration;
 import org.springframework.integration.dsl.core.MessageSourceSpec;
 import org.springframework.integration.dsl.support.PropertiesBuilder;
-import org.springframework.integration.dsl.support.PropertiesConfigurer;
+import org.springframework.integration.dsl.support.PropertiesBuilder.PropertiesConfigurer;
 import org.springframework.integration.mail.AbstractMailReceiver;
 import org.springframework.integration.mail.MailReceivingMessageSource;
 

spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/mail/MailSendingMessageHandlerSpec.java

@@ -21,7 +21,7 @@ import javax.activation.FileTypeMap;
 
 import org.springframework.integration.dsl.core.MessageHandlerSpec;
 import org.springframework.integration.dsl.support.PropertiesBuilder;
-import org.springframework.integration.dsl.support.PropertiesConfigurer;
+import org.springframework.integration.dsl.support.PropertiesBuilder.PropertiesConfigurer;
 import org.springframework.integration.mail.MailSendingMessageHandler;
 import org.springframework.mail.javamail.JavaMailSenderImpl;
 

spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/support/MapBuilder.java

@@ -0,0 +1,53 @@
+/*
+ * 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.integration.dsl.support;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.springframework.expression.spel.standard.SpelExpressionParser;
+
+/**
+ * @author Artem Bilan
+ */
+public class MapBuilder<B extends MapBuilder<B, K, V>, K, V> {
+
+	protected final static SpelExpressionParser PARSER = new SpelExpressionParser();
+
+	private final Map<K, V> map = new HashMap<K, V>();
+
+	public B put(K key, V value) {
+		this.map.put(key, value);
+		return _this();
+	}
+
+	public Map<K, V> get() {
+		return this.map;
+	}
+
+	@SuppressWarnings("unchecked")
+	protected final B _this() {
+		return (B) this;
+	}
+
+	public interface MapBuilderConfigurer<B extends MapBuilder<B, K, V>, K, V> {
+
+		void configure(MapBuilder<B, K, V> builder);
+
+	}
+
+}

spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/support/PropertiesBuilder.java

@@ -20,6 +20,7 @@ import java.util.Properties;
 
 /**
  * @author Gary Russell
+ * @author Artem Bilan
  *
  */
 public class PropertiesBuilder {
@@ -35,4 +36,10 @@ public class PropertiesBuilder {
 		return this.properties;
 	}
 
+	public interface PropertiesConfigurer {
+
+		void configure(PropertiesBuilder propertiesBuilder);
+
+	}
+
 }

spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/support/StringStringMapBuilder.java

@@ -13,14 +13,14 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.springframework.integration.dsl.support;
 
 /**
- * @author Artem Bilan
+ * A map builder creating a map with String keys and values.
+ *
+ * @author Gary Russell
+ *
  */
-public interface PropertiesConfigurer {
-
-	void configure(PropertiesBuilder propertiesBuilder);
+public class StringStringMapBuilder extends MapBuilder<StringStringMapBuilder, String, String> {
 
 }

spring-integration-java-dsl/src/test/java/org/springframework/integration/dsl/test/mail/MailTests.java

@@ -129,18 +129,14 @@ public class MailTests {
 	private ImapIdleChannelAdapter imapIdleAdapter;
 
 	@Test
-	public void testOutbound() throws Exception {
+	public void testSmtp() throws Exception {
 		assertEquals("localhost", TestUtils.getPropertyValue(this.sendMailHandler, "mailSender.host"));
 
 		Properties javaMailProperties = TestUtils.getPropertyValue(this.sendMailHandler,
 				"mailSender.javaMailProperties", Properties.class);
 		assertEquals("true", javaMailProperties.getProperty("mail.debug"));
 
-		this.sendMailChannel.send(MessageBuilder.withPayload("foo")
-				.setHeader(MailHeaders.SUBJECT, "foo")
-				.setHeader(MailHeaders.FROM, "foo@bar")
-				.setHeader(MailHeaders.TO, "bar@baz")
-				.build());
+		this.sendMailChannel.send(MessageBuilder.withPayload("foo").build());
 
 		int n = 0;
 		while (n++ < 100 && smtpServer.getMessages().size() == 0) {
@@ -163,8 +159,8 @@ public class MailTests {
 		assertNotNull(message);
 		MimeMessage mm = (MimeMessage) message.getPayload();
 		assertEquals("foo@bar", mm.getRecipients(RecipientType.TO)[0].toString());
-		assertEquals("bar@baz", mm.getFrom()[0].toString());
-		assertEquals("Test Email", mm.getSubject());
+		assertEquals("bar@baz", message.getHeaders().get(MailHeaders.FROM));
+		assertEquals("Test Email", message.getHeaders().get(MailHeaders.SUBJECT));
 		assertEquals("foo\r\n", mm.getContent());
 	}
 
@@ -199,6 +195,7 @@ public class MailTests {
 		@Bean
 		public IntegrationFlow sendMailFlow() {
 			return IntegrationFlows.from("sendMailChannel")
+					.enrichHeaders(Mail.headers().subject("foo").from("foo@bar").to("bar@baz"))
 					.handle(Mail.outboundAdapter("localhost")
 									.port(smtpPort)
 									.credentials("user", "pw")
@@ -215,6 +212,8 @@ public class MailTests {
 									.javaMailProperties(p -> p.put("mail.debug", "true")),
 							e -> e.autoStartup(true)
 									.poller(Pollers.fixedDelay(1000)))
+					.enrichHeaders(s -> s.headerExpressions(c -> c.put(MailHeaders.SUBJECT, "payload.subject")
+									.put(MailHeaders.FROM, "payload.from[0].toString()")))
 					.channel(MessageChannels.queue("pop3Channel"))
 					.get();
 		}