CAMEL-9880: Header Support for Attachments in Camel 2.18

camel-core/src/main/java/org/apache/camel/Attachment.java

@@ -0,0 +1,83 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.apache.camel;
+
+import java.util.Collection;
+import java.util.List;
+
+import javax.activation.DataHandler;
+
+/**
+ * Represents an attachment as part of a {@link Message}.
+ */
+public interface Attachment {
+    /**
+     * Return a DataHandler for the content within this attachment.
+     *
+     * @return DataHandler for the content
+     */
+    DataHandler getDataHandler();
+
+    /**
+     * Get all the headers for this header name. Returns null if no headers for
+     * this header name are available.
+     *
+     * @param headerName he name of this header
+     * @return a comma separated list of all header values
+     */
+    String getHeader(String headerName);
+
+    /**
+     * Get all the headers for this header name. Returns null if no headers for
+     * this header name are available.
+     *
+     * @param headerName he name of this header
+     * @return a list of all header values
+     */
+    List<String> getHeaderAsList(String name);
+
+    /**
+     * Get all header names for this attachment.
+     *
+     * @return a collection of all header names
+     */
+    Collection<String> getHeaderNames();
+
+    /**
+     * Set the value for this headerName. Replaces all existing header values
+     * with this new value.
+     * 
+     * @param headerName the name of this header
+     * @param headerValue the value for this header
+     */
+    void setHeader(String headerName, String headerValue);
+
+    /**
+     * Add this value to the existing values for this headerName.
+     * 
+     * @param headerName the name of this header
+     * @param headerValue the value for this header
+     */
+    void addHeader(String headerName, String headerValue);
+
+    /**
+     * Remove all headers with this name.
+     * 
+     * @param headerName the name of this header
+     */
+    void removeHeader(String headerName);
+}

camel-core/src/main/java/org/apache/camel/AttachmentObjects.java

@@ -0,0 +1,35 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.apache.camel;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Marks a parameter as being Map of attachments as {@link Attachment} objects
+ * of an inbound {@link Message}
+ * 
+ * @version
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@Target({ElementType.PARAMETER })
+public @interface AttachmentObjects {
+}

camel-core/src/main/java/org/apache/camel/Attachments.java

@@ -23,9 +23,10 @@
 import java.lang.annotation.Target;
 
 /**
- * Marks a parameter as being Map of attachments of an inbound {@link Message}
+ * Marks a parameter as being Map of attachments as
+ * {@link javax.activation.DataHandler} objects of an inbound {@link Message}
  * 
- * @version 
+ * @version
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Documented

camel-core/src/main/java/org/apache/camel/Message.java

@@ -255,6 +255,14 @@ public interface Message {
      */
     DataHandler getAttachment(String id);
 
+    /**
+     * Returns the attachment specified by the id
+     *
+     * @param id the id under which the attachment is stored
+     * @return the attachment or <tt>null</tt>
+     */
+    Attachment getAttachmentObject(String id);
+
     /**
      * Returns a set of attachment names of the message
      *
@@ -277,20 +285,42 @@ public interface Message {
      */
     void addAttachment(String id, DataHandler content);
 
+    /**
+     * Adds an attachment to the message using the id
+     *
+     * @param id        the id to store the attachment under
+     * @param content   the attachment
+     */
+    void addAttachmentObject(String id, Attachment content);
+
     /**
      * Returns all attachments of the message
      *
      * @return the attachments in a map or <tt>null</tt>
      */
     Map<String, DataHandler> getAttachments();
 
+    /**
+     * Returns all attachments of the message
+     *
+     * @return the attachments in a map or <tt>null</tt>
+     */
+    Map<String, Attachment> getAttachmentObjects();
+
     /**
      * Set all the attachments associated with this message
      *
      * @param attachments the attachments
      */
     void setAttachments(Map<String, DataHandler> attachments);
 
+    /**
+     * Set all the attachments associated with this message
+     *
+     * @param attachments the attachments
+     */
+    void setAttachmentObjects(Map<String, Attachment> attachments);
+
     /**
      * Returns whether this message has attachments.
      *

camel-core/src/main/java/org/apache/camel/builder/ExpressionBuilder.java

@@ -80,6 +80,42 @@ public final class ExpressionBuilder {
     private ExpressionBuilder() {
     }
 
+     /**
+     * Returns an expression for the inbound message attachments
+     *
+     * @return an expression object which will return the inbound message attachments
+     */
+    public static Expression attachmentObjectsExpression() {
+        return new ExpressionAdapter() {
+            public Object evaluate(Exchange exchange) {
+                return exchange.getIn().getAttachmentObjects();
+            }
+
+            @Override
+            public String toString() {
+                return "attachmentObjects";
+            }
+        };
+    }
+
+    /**
+     * Returns an expression for the inbound message attachments
+     *
+     * @return an expression object which will return the inbound message attachments
+     */
+    public static Expression attachmentObjectValuesExpression() {
+        return new ExpressionAdapter() {
+            public Object evaluate(Exchange exchange) {
+                return exchange.getIn().getAttachmentObjects().values();
+            }
+
+            @Override
+            public String toString() {
+                return "attachmentObjects";
+            }
+        };
+    }
+
     /**
      * Returns an expression for the inbound message attachments
      *

camel-core/src/main/java/org/apache/camel/builder/ExpressionClauseSupport.java

@@ -171,7 +171,7 @@ public T outHeaders() {
      * An expression of the inbound message attachments
      */
     public T attachments() {
-        return expression(ExpressionBuilder.attachmentValuesExpression());
+        return expression(ExpressionBuilder.attachmentObjectValuesExpression());
     }
 
     /**

camel-core/src/main/java/org/apache/camel/component/bean/BeanInfo.java

@@ -32,6 +32,7 @@
 import java.util.Map;
 import java.util.Set;
 
+import org.apache.camel.AttachmentObjects;
 import org.apache.camel.Attachments;
 import org.apache.camel.Body;
 import org.apache.camel.CamelContext;
@@ -946,7 +947,9 @@ private Expression createParameterUnmarshalExpression(Class<?> clazz, Method met
 
     private Expression createParameterUnmarshalExpressionForAnnotation(Class<?> clazz, Method method, 
             Class<?> parameterType, Annotation annotation) {
-        if (annotation instanceof Attachments) {
+        if (annotation instanceof AttachmentObjects) {
+            return ExpressionBuilder.attachmentObjectsExpression();
+        } else if (annotation instanceof Attachments) {
             return ExpressionBuilder.attachmentsExpression();
         } else if (annotation instanceof Property) {
             Property propertyAnnotation = (Property)annotation;

camel-core/src/main/java/org/apache/camel/converter/AttachmentConverter.java

@@ -0,0 +1,43 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.apache.camel.converter;
+
+import javax.activation.DataHandler;
+
+import org.apache.camel.Attachment;
+import org.apache.camel.Converter;
+
+/**
+ * Some useful converters for {@link Attachment}
+ * to a {@link DataHandler}
+ *
+ * @version 
+ */
+@Converter
+public final class AttachmentConverter {
+
+    /**
+     * Utility classes should not have a public constructor.
+     */
+    private AttachmentConverter() {
+    }
+
+    @Converter
+    public static DataHandler toDataHandler(final Attachment attachment) {
+        return attachment.getDataHandler();
+    }
+}