com.softwareag.eda.nerv

Interface MessageCreator

public interface MessageCreator

Used for creating Camel message objects out of EDA events.

See Also:

EventTypeXSDConstants} - Contains constants that should be used for populating message headers maps., EventTypeXSDConstants#buildCustomHeaderKey(String)} - Used for building customer header map keys., Message#getHeaders()} - Used for accessing all message headers. There are three categories of EDA headers in the Camel Message:
1) Standard headers, i.e. the header elements described in the Envelope schema, such as: Type, Start, End, EventID, etc.
2) Custom headers, i.e. the children of the CustomHeaders element
3) Filterable properties, i.e. all elements from the body, which are annotated as filterable in the event type schema.
, Message#getHeader(String)} - Used for accessing a specific message header.
1) Standard headers can be accessed by using the EventTypeXSDConstants.STANDARD_HEADER_XXX constants, e.g. Message.getHeader(EventTypeXSDConstants.STANDARD_HEADER_TYPE) will return {http://namespaces.softwareag.com/EDA/WebM/Sample/InventoryMgmt/1.0}PartInventoryLow.
2) Custom headers can be accessed by using the {@link EventTypeXSDConstants#buildCustomHeaderKey(String)} method, e.g. Message.getHeader(EventTypeXSDConstants.buildCustomHeaderKey("MyHeader")) will return MyValue.
3) Filterable properties can be accessed by following the convention below:
3.1) If the filterable element is a child of the root element use: Message.getHeader("elementName"), e.g.: Message.getHeader("InventoryLevel") will return 2.
3.2) If the filterable element is a child of a complex element use: Message.getHeader("elementName" + EventTypeXSDConstants.FILTERABLE_PROPS_PATH_SEPARATOR + "elementName") , e.g.: Message.getHeader("Part" + EventTypeXSDConstants.FILTERABLE_PROPS_PATH_SEPARATOR + "ItemID") will return itemID., Message#getHeader(String, Class)} - Used for accessing a specific message header and casting it to the right Java type, usually java.lang.String. For example Message.getHeader(EventTypeXSDConstants.STANDARD_HEADER_TYPE, String.class) returns a string object which you don't have to cast explicitly like in the Message#getHeader(String) method., Message#getBody()} - Used for accessing the message body. In the example above Message.getBody() will return:

      <PartInventoryLow xmlns="http://namespaces.softwareag.com/EDA/WebM/Sample/InventoryMgmt/1.0">
          <Part>
              <ItemID>itemID</ItemID>
              <ItemName>itemName</ItemName>
              <Model>model</Model>
              <Color>color</Color>
              <Shape>shape</Shape>
          </Part>
          <InventoryLevel>2</InventoryLevel>
          <DesiredInventoryLevel>1</DesiredInventoryLevel>
      </PartInventoryLow>
 

Method Summary

Methods

Modifier and Type	Method and Description
java.util.Map<java.lang.String,java.lang.Object>	createHeadersMap() Creates a map that can hold event headers and is optimize to be used with Camel messages.
org.apache.camel.Message	createMessage(java.lang.Object bodyAsPOJO, java.util.Map<java.lang.String,java.lang.Object> headers) Creates a Camel message object from the specified event body and headers.
org.apache.camel.Message	createMessage(java.lang.String eventAsXMLString) Creates a Camel message object from the specified event.
org.apache.camel.Message	createMessage(java.lang.String bodyAsXMLString, java.util.Map<java.lang.String,java.lang.Object> headers) Creates a Camel message object from the specified event body and headers.
org.apache.camel.Message	createMessageExtractFilterableProperties(java.lang.Object bodyAsPOJO, java.util.Map<java.lang.String,java.lang.Object> headers) Creates a Camel message object from the specified event body and headers.
org.apache.camel.Message	createMessageExtractFilterableProperties(java.lang.String bodyAsXMLString, java.util.Map<java.lang.String,java.lang.Object> headers) Creates a Camel message object from the specified event body and headers.
java.lang.String	dateToString(long timeInMillis) Converts a Java date represented in milliseconds to a string that can be used with events.
java.lang.String	generateEventID() Generates a pseudo unique event ID.

Method Detail

createMessage

org.apache.camel.Message createMessage(java.lang.String eventAsXMLString)
                                       throws NervException

Creates a Camel message object from the specified event. The event should be in the form of an XML string containing the whole event envelope - both headers and body.

Please note that using this method will lead to a serious performance degradation as XML and XSD parsing is involved. Consider using one of createMessage(String, Map), createMessage(Object, Map) for better performance.

The newly created message is built the following way:

• The event type is extracted from the event headers thus its presence is mandatory.
• All event headers are extracted and set as message headers. Could be retrieved with Message.getHeaders(), Message.getHeader(String), and Message.getHeader(String, Class).
• All filterable properties are extracted and set as message headers. Could be retrieved with Message.getHeaders(), Message.getHeader(String), and Message.getHeader(String, Class).
• The event body is extracted and set as message body. Could be retrieved with Message.getBody().

Sample input:

      <eda:Event xmlns:eda="http://namespaces.softwareag.com/EDA/Event">
          <eda:Header>
              <eda:Type>{http://namespaces.softwareag.com/EDA/WebM/Sample/InventoryMgmt/1.0}PartInventoryLow</eda:Type>
              <eda:Start>2012-04-05T17:09:33.112+03:00</eda:Start>
              <eda:End>2012-04-05T17:09:44.112+03:00</eda:End>
              <eda:Kind>Event</eda:Kind>
              <eda:CustomHeaders>
                  <eda:MyHeader>MyValue</eda:MyHeader>
              </eda:CustomHeaders>
          </eda:Header>
          <eda:Body>
              <PartInventoryLow xmlns="http://namespaces.softwareag.com/EDA/WebM/Sample/InventoryMgmt/1.0">
                  <Part>
                      <ItemID>itemID</ItemID>
                      <ItemName>itemName</ItemName>
                      <Model>model</Model>
                      <Color>color</Color>
                      <Shape>shape</Shape>
                  </Part>
                  <InventoryLevel>2</InventoryLevel>
                  <DesiredInventoryLevel>1</DesiredInventoryLevel>
              </PartInventoryLow>
          </eda:Body>
      </eda:Event>
 

Usage:

 String eventAsXMLString = "<Event>... some valid event as an XML string like the one above ...</Event>";
 
 Message message = MessageCreator.createMessage(eventAsXMLString);
 

Parameters:

eventAsXMLString - - The event in the form of an XML string. Cannot be null or an empty string.

Returns:

A newly created Camel message based on the specified event. The headers of this message correspond to the headers specified by the Header tag of the XML string and the body of the message corresponds to the content specified by the Body tag of the XML string.

Throws:

NervException - If the specified event is null or empty. Also if one or more of the required headers, like the event type, are missing or event body is not present.

createMessage

org.apache.camel.Message createMessage(java.lang.String bodyAsXMLString,
                                     java.util.Map<java.lang.String,java.lang.Object> headers)
                                       throws NervException

Creates a Camel message object from the specified event body and headers. The event body should be in the form of an XML string.

The newly created message is built the following way:

• The event type is extracted from the headers map thus it's presence is mandatory.
• The event headers are set as message headers. Could be retrieved with Message.getHeaders() and Message.getHeader(String).
• The event body is set as message body as is. This means that the method does not perform any data validation and the user is fully responsible for the content being provided. Also this method does not automatically extract filterable properties from the body which means that the user is responsible for placing these properties in the headers map prior to invoking this method. Could be retrieved with Message.getBody() after the message is created.

Sample input:

      <PartInventoryLow xmlns="http://namespaces.softwareag.com/EDA/WebM/Sample/InventoryMgmt/1.0">
          <Part>
              <ItemID>itemID</ItemID>
              <ItemName>itemName</ItemName>
              <Model>model</Model>
              <Color>color</Color>
              <Shape>shape</Shape>
          </Part>
          <InventoryLevel>2</InventoryLevel>
          <DesiredInventoryLevel>1</DesiredInventoryLevel>
      </PartInventoryLow>
 

Usage:

 Map<String, Object> headers = MessageCreator.createHeadersMap();
 headers.put(EventTypeXSDConstants.STANDARD_HEADER_TYPE, "{http://namespaces.softwareag.com/EDA/WebM/Sample/InventoryMgmt/1.0}PartInventoryLow<");
 headers.put(EventTypeXSDConstants.buildCustomHeaderKey("MyHeader"), "MyValue");
 headers.put("Part" + EventTypeXSDConstants.FILTERABLE_PROPS_PATH_SEPARATOR + "ItemID", "itemID");
 headers.put("Part" + EventTypeXSDConstants.FILTERABLE_PROPS_PATH_SEPARATOR + "ItemName", "itemName");
 headers.put("InventoryLevel", "2");
 String bodyAsXMLString = "... some valid event body as an XML string like the one above ...";
 Message message = MessageCreator.createMessage(bodyAsXMLString, headers);
 

Parameters:

bodyAsXMLString - - The event in the form of an XML string. Cannot be null.

headers - - A map containing all event headers and filterable properties. Please note that this method does not perform any processing of the body thus it will not extract filterable properties from it. The user is responsible for providing all required headers and filterable properties prior to invoking this method. Cannot be null or empty.

Returns:

A newly created Camel message based on the specified event body and headers.

Throws:

NervException - If the specified event body or headers map is null or the map is empty. Also if one or more of the required headers, like the event type, are missing.

createMessage

org.apache.camel.Message createMessage(java.lang.Object bodyAsPOJO,
                                     java.util.Map<java.lang.String,java.lang.Object> headers)
                                       throws NervException

Creates a Camel message object from the specified event body and headers. The event body should be in the form of a Java object containing annotations for XML Binding.

The newly created message is built the following way:

• The event type is extracted from the headers map thus its presence is mandatory.
• The event headers are set as message headers. Could be retrieved with Message.getHeaders() and Message.getHeader(String).
• The event body is marshalled to an XML string and set as message body as is. This means that the method does not perform any data validation and the user is fully responsible for the content being provided. Also this method does not automatically extract filterable properties from the body which means that the user is responsible for placing these properties in the headers map prior to invoking this method. Could be retrieved with Message.getBody() after the message is created. In order to convert it back to a Java object you'll have to unmarshal the output of the Message.getBody() method with XML Binding.

Usage:

 Map<String, Object> headers = MessageCreator.createHeadersMap();
 headers.put(EventTypeXSDConstants.STANDARD_HEADER_TYPE, "{http://namespaces.softwareag.com/EDA/WebM/Sample/InventoryMgmt/1.0}PartInventoryLow");
 headers.put(EventTypeXSDConstants.buildCustomHeaderKey("MyHeader"), "MyValue");
 headers.put("Part" + EventTypeXSDConstants.FILTERABLE_PROPS_PATH_SEPARATOR + "ItemID", "itemID");
 headers.put("Part" + EventTypeXSDConstants.FILTERABLE_PROPS_PATH_SEPARATOR + "ItemName", "itemName");
 headers.put("InventoryLevel", "2");
 PartInventoryLowType bodyAsPOJO = new PartInventoryLowType(); // A valid Java object which contains annotations for XML Binding.
 Message message = MessageCreator.createMessage(bodyAsPOJO, headers);
 

Parameters:

bodyAsPOJO - - The event body in the form of a Java object. Cannot be null. Also the class of this object should contain annotations for XML Binding so this method is capable of marshalling it to an XML string library.

headers - - A map containing all event headers and filterable properties. Please note that this method does not perform any processing of the body thus it will not extract filterable properties from it. The user is responsible for providing all required headers and filterable properties prior to invoking this method.

Returns:

A newly created Camel message based on the specified event body and headers.

Throws:

NervException - If the specified event body or headers map is null or the map is empty. Also if one or more of the required headers, like the event type, are missing.

createMessageExtractFilterableProperties

org.apache.camel.Message createMessageExtractFilterableProperties(java.lang.String bodyAsXMLString,
                                                                java.util.Map<java.lang.String,java.lang.Object> headers)
                                                                  throws NervException

Creates a Camel message object from the specified event body and headers. The event body should be in the form of an XML string.

The newly created message is built the following way:

• The event type is extracted from the headers map thus it's presence is mandatory.
• The event headers are set as message headers. The filterable properties are calculated based on the event type from the event body. The calculated values are added to the headers or if present overwrite the values in the message headers provided. This method should be used to ensure that the filterable properties are correctly set in the headers. Since this requires parsing and validating of the body, calling the method is time-consuming. Could be retrieved with Message.getHeaders() and Message.getHeader(String).
• The event body is set as message body. This means that the method does not perform any data validation and the user is fully responsible for the content being provided. Could be retrieved with Message.getBody() after the message is created.

Sample input:

      <PartInventoryLow xmlns="http://namespaces.softwareag.com/EDA/WebM/Sample/InventoryMgmt/1.0">
          <Part>
              <ItemID>itemID</ItemID>
              <ItemName>itemName</ItemName>
              <Model>model</Model>
              <Color>color</Color>
              <Shape>shape</Shape>
          </Part>
          <InventoryLevel>2</InventoryLevel>
          <DesiredInventoryLevel>1</DesiredInventoryLevel>
      </PartInventoryLow>
 

Usage:

 Map<String, Object> headers = MessageCreator.createHeadersMap();
 headers.put(EventTypeXSDConstants.STANDARD_HEADER_TYPE, "{http://namespaces.softwareag.com/EDA/WebM/Sample/InventoryMgmt/1.0}PartInventoryLow<");
 headers.put(EventTypeXSDConstants.buildCustomHeaderKey("MyHeader"), "MyValue");
 String bodyAsXMLString = "... some valid event body as an XML string like the one above ...";
 Message message = MessageCreator.createMessageExtractFilterableProperties(bodyAsXMLString, headers);
 

Afterwards the header property "InventoryLevel" is set to "2", "Part$ItemID" is set to "itemID", and "Part$ItemName" is set to "itemName".

Parameters:

bodyAsXMLString - - The event in the form of an XML string. Cannot be null.

headers - - A map containing all event headers and filterable properties. Filterable properties set may be overwritten. The user is responsible for providing all required headers prior to invoking this method. Cannot be null or empty.

Returns:

A newly created Camel message based on the specified event body and headers. Filterable properties in the headers are calculated.

Throws:

NervException - If the specified event body or headers map is null or the map is empty. Also if one or more of the required headers, like the event type, are missing.

createMessageExtractFilterableProperties

org.apache.camel.Message createMessageExtractFilterableProperties(java.lang.Object bodyAsPOJO,
                                                                java.util.Map<java.lang.String,java.lang.Object> headers)
                                                                  throws NervException

Creates a Camel message object from the specified event body and headers. The event body should be in the form of a Java object containing annotations for XML Binding.

The newly created message is built the following way:

• The event type is extracted from the headers map thus it's presence is mandatory.
• The event headers are set as message headers. Could be retrieved with Message.getHeaders() and Message.getHeader(String).
• The event body is marshalled to an XML string and set as message body. The filterable properties are calculated based on the event type from the event body. The calculated values are added to the headers or if present overwrite the values in the message headers provided. This method should be used to ensure that the filterable properties are correctly set in the headers. Since this requires parsing of the body, calling the method is time-consuming. Could be retrieved with Message.getBody() after the message is created. In order to convert it back to a Java object you'll have to unmarshal the output of the Message.getBody() method with XML Binding.

Usage:

 Map<String, Object> headers = MessageCreator.createHeadersMap();
 headers.put(EventTypeXSDConstants.STANDARD_HEADER_TYPE, "{http://namespaces.softwareag.com/EDA/WebM/Sample/InventoryMgmt/1.0}PartInventoryLow<");
 headers.put(EventTypeXSDConstants.buildCustomHeaderKey("MyHeader"), "MyValue");
 PartInventoryLowType bodyAsPOJO = new PartInventoryLowType(); // A valid Java object which contains annotations for XML Binding.
 Message message = MessageCreator.createMessageExtractFilterableProperties(bodyAsPOJO, headers);
 

Parameters:

bodyAsPOJO - - The event body in the form of a Java object. Cannot be null. Also the class of this object should contain annotations for XML Binding so this method is capable of marshalling it to an XML string library.

headers - - A map containing all event headers and filterable properties. Filterable properties set may be overwritten. The user is responsible for providing all required headers prior to invoking this method. Cannot be null or empty.

Returns:

A newly created Camel message based on the specified event body and headers. Filterable properties in the headers are calculated.

Throws:

NervException - If the specified event body or headers map is null or the map is empty. Also if one or more of the required headers, like the event type, are missing.

generateEventID

java.lang.String generateEventID()

Generates a pseudo unique event ID.

Usage:

 Map<String, Object> headers = MessageCreator.createHeadersMap();
 headers.put(EventTypeXSDConstants.STANDARD_HEADER_TYPE, "{http://namespaces.softwareag.com/EDA/WebM/Sample/InventoryMgmt/1.0}PartInventoryLow");
 headers.put(EventTypeXSDConstants.STANDARD_HEADER_EVENTID, MessageCreator.generateEventID());
 headers.put("Part$ItemID", "itemID");
 headers.put("Part$ItemName", "itemName");
 headers.put("InventoryLevel", "2");
 PartInventoryLowType bodyAsPOJO = new PartInventoryLowType(); // A valid Java object which contains annotations for XML Binding.
 Message message = MessageCreator.createMessage(bodyAsXMLString, headers);
 

By default createMessage generates a unique eventID automatically, but it can be explicitly overwritten by using the coding example above.

Returns:

The generated event ID.

createHeadersMap

java.util.Map<java.lang.String,java.lang.Object> createHeadersMap()

Creates a map that can hold event headers and is optimize to be used with Camel messages.

Returns:

A Camel-ready map optimized to hold event headers. Use this method instead of other standard Java map implementations in order to optimize performance.

dateToString

java.lang.String dateToString(long timeInMillis)

Converts a Java date represented in milliseconds to a string that can be used with events. The result will comply with the date format pattern set by Software AG EDA convention.

Parameters:

timeInMillis - - The Java date represented in milliseconds that has to be formatted and converted to a string.

Returns:

A string representing the given date that complies with EDA convention.