{"type":"doc","content":[{"type":"paragraph","content":[{"text":"Apache Camel supports a variety of approaches to transforming message content. In addition to a simple native API for modifying message content, Apache Camel supports integration with several different third-party libraries and transformation standards.","type":"text"}]},{"type":"extension","attrs":{"layout":"default","extensionType":"com.atlassian.confluence.macro.core","extensionKey":"toc","parameters":{"macroParams":{"minLevel":{"value":"1"},"maxLevel":{"value":"7"}},"macroMetadata":{"macroId":{"value":"5d20c9cdc0a8f710b937857dfda7313c"},"schemaVersion":{"value":"1"},"title":"Table of Contents"}},"localId":"bd9ad975-a9ac-437f-95d1-6b2ee3aa7cda"}},{"type":"heading","attrs":{"level":3},"content":[{"text":"Simple Message Transformations","type":"text"}]},{"type":"paragraph","content":[{"text":"The DSL associated with Camel have a built-in API that enables you to perform simple transformations on incoming and outgoing messages. For example, the rule shown below will append the text of “World” to the end of an incoming message body.","type":"text"}]},{"type":"codeBlock","content":[{"text":"from(\"SourceURL\").setBody(body().append(\" World!\")).to(\"TargetURL\");","type":"text"}]},{"type":"paragraph","content":[{"text":"NOTE:","type":"text","marks":[{"type":"strong"}]},{"text":" The use of the ","type":"text"},{"text":"setBody ","type":"text","marks":[{"type":"code"}]},{"text":"command to replace the content of the incoming message.","type":"text"}]},{"type":"heading","attrs":{"level":3},"content":[{"text":"API for simple transformations","type":"text"}]},{"type":"paragraph","content":[{"text":"We can utilize the following API classes to perform simple transformations of the message content in a router rule:","type":"text"}]},{"type":"bulletList","content":[{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"org.apache.camel.model.ProcessorDefinition","type":"text","marks":[{"type":"code"}]}]},{"type":"paragraph","content":[{"text":"org.apache.camel.builder.Builder","type":"text","marks":[{"type":"code"}]}]},{"type":"paragraph","content":[{"text":"org.apache.camel.builder.ValueBuilder","type":"text","marks":[{"type":"code"}]}]}]}]},{"type":"heading","attrs":{"level":3},"content":[{"text":"ProcessorDefinition class","type":"text"}]},{"type":"paragraph","content":[{"text":"The ","type":"text"},{"text":"org.apache.camel.model.ProcessorDefinition","type":"text","marks":[{"type":"code"}]},{"text":" class defines the DSL commands you can insert directly into a router rule:","type":"text"}]},{"type":"table","attrs":{"layout":"default","localId":"6e208307-d998-4f46-9aff-129196be1e12"},"content":[{"type":"tableRow","content":[{"type":"tableHeader","attrs":{"colspan":1,"rowspan":1,"colwidth":[340.0]},"content":[{"type":"paragraph","content":[{"text":"Method","type":"text","marks":[{"type":"strong"}]}]}]},{"type":"tableHeader","attrs":{"colspan":1,"rowspan":1,"colwidth":[340.0]},"content":[{"type":"paragraph","content":[{"text":"Description","type":"text","marks":[{"type":"strong"}]}]}]}]},{"type":"tableRow","content":[{"type":"tableCell","attrs":{"colspan":1,"rowspan":1,"colwidth":[340.0]},"content":[{"type":"paragraph","content":[{"text":"Type convertBodyTo(Class type)","type":"text","marks":[{"type":"code"}]}]}]},{"type":"tableCell","attrs":{"colspan":1,"rowspan":1,"colwidth":[340.0]},"content":[{"type":"paragraph","content":[{"text":"Converts the IN message body to the specified 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message.","type":"text"}]}]}]},{"type":"tableRow","content":[{"type":"tableCell","attrs":{"colspan":1,"rowspan":1,"colwidth":[340.0]},"content":[{"type":"paragraph","content":[{"text":"ExpressionClause> setOutHeader(String name)","type":"text","marks":[{"type":"code"}]}]}]},{"type":"tableCell","attrs":{"colspan":1,"background":"initial","rowspan":1,"colwidth":[340.0]},"content":[{"type":"paragraph","content":[{"text":"Adds a processor which sets the header on the OUT message.","type":"text"}]}]}]},{"type":"tableRow","content":[{"type":"tableCell","attrs":{"colspan":1,"rowspan":1,"colwidth":[340.0]},"content":[{"type":"paragraph","content":[{"text":"Type setOutHeader(String name, Expression expression)","type":"text","marks":[{"type":"code"}]}]}]},{"type":"tableCell","attrs":{"colspan":1,"background":"initial","rowspan":1,"colwidth":[340.0]},"content":[{"type":"paragraph","content":[{"text":"Adds a processor which sets the header on the OUT 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message.","type":"text"}]}]}]}]},{"type":"heading","attrs":{"level":3},"content":[{"text":"Builder class","type":"text"}]},{"type":"paragraph","content":[{"text":"The ","type":"text"},{"text":"org.apache.camel.builder.Builder","type":"text","marks":[{"type":"code"}]},{"text":" class will provide us access to message content in contexts where expressions or predicates are expected. Thus, ","type":"text"},{"text":"Builder","type":"text","marks":[{"type":"code"}]},{"text":" methods are typically invoked in the arguments of DSL commands. ","type":"text"}]},{"type":"heading","attrs":{"level":3},"content":[{"text":"ValueBuilder class","type":"text"}]},{"type":"paragraph","content":[{"text":"The ","type":"text"},{"text":"org.apache.camel.builder.ValueBuilder","type":"text","marks":[{"type":"code"}]},{"text":" class will enable us to modify values returned by the ","type":"text"},{"text":"Builder","type":"text","marks":[{"type":"code"}]},{"text":" methods. In other words, the methods in ","type":"text"},{"text":"ValueBuilder","type":"text","marks":[{"type":"code"}]},{"text":" provide a simple way of modifying message content.","type":"text"}]},{"type":"heading","attrs":{"level":3},"content":[{"text":"Marshalling and Unmarshalling","type":"text"}]},{"type":"paragraph","content":[{"text":"We are able to convert between low-level and high-level message formats using these commands:","type":"text"}]},{"type":"bulletList","content":[{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"marshal()","type":"text","marks":[{"type":"code"}]},{"text":" — Converts a high-level data format to a low-level data format.","type":"text"}]},{"type":"paragraph","content":[{"text":"unmarshal","type":"text","marks":[{"type":"code"}]},{"text":"() — Converts a low-level data format to a high-level data format.","type":"text"}]}]}]},{"type":"paragraph","content":[{"text":"Apache Camel supports marshalling and unmarshalling of the following data formats:","type":"text"}]},{"type":"bulletList","content":[{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Java serialization","type":"text"}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"JAXB","type":"text"}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"XMLBeans","type":"text"}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"XStream","type":"text"}]}]}]},{"type":"heading","attrs":{"level":4},"content":[{"text":"Java serialization","type":"text"}]},{"type":"paragraph","content":[{"text":"This process will enable us to convert a Java object to a blob of binary data. Using this data format, ","type":"text"},{"text":"unmarshalling ","type":"text","marks":[{"type":"em"}]},{"text":"converts a binary blob to a Java object, and ","type":"text"},{"text":"marshalling ","type":"text","marks":[{"type":"em"}]},{"text":"converts a Java object to a binary blob. For example, to read a serialized Java object from an endpoint, ","type":"text"},{"text":"SourceURL","type":"text","marks":[{"type":"em"}]},{"text":", and convert it to a Java object, you use a rule like the following:","type":"text"}]},{"type":"codeBlock","content":[{"text":"from(\"SourceURL\").unmarshal().serialization()\n..to(\"TargetURL\");","type":"text"}]},{"type":"paragraph","content":[{"text":"Or alternatively, in Spring XML:","type":"text"}]},{"type":"codeBlock","content":[{"text":"\n \n \n \n \n \n ","type":"text"}]},{"type":"heading","attrs":{"level":4},"content":[{"text":"JAXB","type":"text"}]},{"type":"paragraph","content":[{"text":"This option provides a mapping between XML schema types and Java types With the use of JAXB, ","type":"text"},{"text":"unmarshalling ","type":"text","marks":[{"type":"em"}]},{"text":"converts an XML data type to a Java object, and ","type":"text"},{"text":"marshalling ","type":"text","marks":[{"type":"em"}]},{"text":"converts a Java object to an XML type. ","type":"text"}]},{"type":"paragraph","content":[{"text":"Before we can begin to use JAXB data formats, we must compile our XML schema with a JAXB compiler to generate the necessary Java classes that represent the XML data types in the schema (known as ","type":"text"},{"text":"binding","type":"text","marks":[{"type":"em"}]},{"text":" the schema). Once the schema is bound, we can define a rule to unmarshal XML data to a Java object, using code like the following:","type":"text"}]},{"type":"codeBlock","content":[{"text":"org.apache.camel.spi.DataFormat jaxb = new \n org.apache.camel.model.dataformat.JaxbDataFormat(\"GeneratedPackageName\");\n\nfrom(\"SourceURL\").unmarshal(jaxb)\n..to(\"TargetURL\");","type":"text"}]},{"type":"paragraph","content":[{"text":"NOTE: ","type":"text","marks":[{"type":"strong"}]},{"text":"Where ","type":"text"},{"text":"GeneratedPackagename","type":"text","marks":[{"type":"em"}]},{"text":" is the name of the Java package generated by the JAXB compiler, that will contain the Java classes representing your XML schema.","type":"text"}]},{"type":"paragraph","content":[{"text":"Or alternatively, in Spring XML:","type":"text"}]},{"type":"codeBlock","content":[{"text":" \n \n \n \n \n \n ","type":"text"}]},{"type":"heading","attrs":{"level":4},"content":[{"text":"XMLBeans","type":"text"}]},{"type":"paragraph","content":[{"text":"Another alternative for our mapping between XML schema types and Java types is the use of XMLBeans. Through it usage, ","type":"text"},{"text":"unmarshalling ","type":"text","marks":[{"type":"em"}]},{"text":"converts an XML data type to a Java object and ","type":"text"},{"text":"marshalling ","type":"text","marks":[{"type":"em"}]},{"text":"converts a Java object to an XML data type. For example, to unmarshal XML data to a Java object using XMLBeans, use code like the following:","type":"text"}]},{"type":"codeBlock","content":[{"text":"from(\"SourceURL\").unmarshal().xmlBeans()\n..to(\"TargetURL\");","type":"text"}]},{"type":"paragraph","content":[{"text":"Or alternatively, in Spring XML:","type":"text"}]},{"type":"codeBlock","content":[{"text":" \n \n \n \n \n \n ","type":"text"}]},{"type":"heading","attrs":{"level":3},"content":[{"text":"Endpoint Bindings","type":"text"}]},{"type":"paragraph","content":[{"text":"What do we mean when we talk about binding? With Apache Camel, a ","type":"text"},{"text":"binding","type":"text","marks":[{"type":"strong"}]},{"text":" is a means of wrapping an endpoint in a contract (ie. by applying a Data Format, a Content Enricher or a validation step). In this scenario, a condition or transformation is applied to the messages coming in, and a complementary condition or transformation is applied to the messages going out.","type":"text"}]},{"type":"heading","attrs":{"level":4},"content":[{"text":"DataFormatBinding","type":"text"}]},{"type":"paragraph","content":[{"text":"The use of the ","type":"text"},{"text":"DataFormatBinding","type":"text","marks":[{"type":"code"}]},{"text":" class is quite useful for those situations where you want to define a binding that marshals and unmarshals a particular data format. In this case, all that you need to do to create a binding is to create a ","type":"text"},{"text":"DataFormatBinding","type":"text","marks":[{"type":"code"}]},{"text":" instance, passing a reference to the relevant data format in the constructor.","type":"text"}]},{"type":"paragraph","content":[{"text":"For example, the following XML DSL code snippet shows a binding (with ID, ","type":"text"},{"text":"jaxb","type":"text","marks":[{"type":"code"}]},{"text":") that is capable of marshalling and unmarshalling the JAXB data format when it is associated with an Apache Camel endpoint:","type":"text"}]},{"type":"paragraph"},{"type":"codeBlock","content":[{"text":"\n ...\n \n \n \n\n \n \n \n \n\n","type":"text"}]},{"type":"heading","attrs":{"level":4},"content":[{"text":"Binding URI","type":"text"}]},{"type":"paragraph","content":[{"text":"To link a binding with an endpoint, we can prefix the endpoint URI with ","type":"text"},{"text":"binding:NameOfBinding","type":"text","marks":[{"type":"code"}]},{"text":", where ","type":"text"},{"text":"NameOfBinding","type":"text","marks":[{"type":"em"}]},{"text":" value is the bean ID of the binding (ie. ID of a binding bean created in Spring XML).","type":"text"}]},{"type":"paragraph","content":[{"text":"For example, the following shows how to associate JMS endpoints with the JAXB binding:","type":"text"}]},{"type":"codeBlock","content":[{"text":"\n ...\n \n \n \n \n \n \n ...\n","type":"text"}]}],"version":1}

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