components/camel-chunk/README.md

# Chunk Component

# Introduction

This component use the Java Chunk library: http://www.x5software.com/chunk/examples/ChunkExample?loc=en_US

Chunk is a Template Engine for Java similar to Apache Velocity, Mustache Java and Freemarker

The **chunk:** component allows for processing a message using a Chunk template. This can be useful when using Templating to build responses for requests. 

Maven users will need to add the following dependency to their pom.xml for this component:

```xml

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-chunk</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

```

# URI format

```

chunk:templateName[?options]

```

# Options

By default the chunk library will scan a default folder "themes" for a specific template, however is possible to define a differente folder to scan using the specific option.
Default extension of template file are .chtml and .cxml, however is possible to define different extension using the specific option.

| Option              | Default | Description                                                                                                            |
|---------------------|---------|------------------------------------------------------------------------------------------------------------------------|
| encoding            | null    | Character encoding of the resource content.                                                                            |
| themesFolder        | null    | Alternative folder to scan for a template name.                                                                        |
| themeSubfolder      | null    | Alternative subfolder to scan for a template name if themeFolder parameter is set.                                     |
| themeLayer          | null    | A specific layer of a template file to use as template.                                                                |
| extension           | null    | Alternative extension to scan for a template name if themeFolder and themeSubfolder are set                            |

# Dynamic Templates

Camel-chunk component provides two headers by which you can define a different resource location for a template or the template content itself. If any of these headers is set then Camel-chunk component uses this over the endpoint configured resource. This allows you to provide a dynamic template at runtime.

| Header                                       | Type      | Description                                                                | Support Version |
|----------------------------------------------|-----------|----------------------------------------------------------------------------|-----------------|
| ChunkConstants.CHUNK_RESOURCE_URI            | String    | A URI for the template resource to use instead of the endpoint configured. |                 |
| ChunkConstants.CHUNK_TEMPLATE                | String    | The template to use instead of the endpoint configured.                    |                 |

# Examples

**Example 1**

```java
	from("direct:in")
            .to("chunk://file")
            .to("direct:out");
```

In this example the chunk component will look for file.chtml template in themes folder and it will use it as template.

**Example 2**

```java
	from("direct:in")
            .to("chunk:example?themeLayer=example_1")
```

In this example the chunk component will look for example.chtml in themes folder and will use the #example_1 layer

**Example 3**

```java
	from("direct:in")
            .to("chunk://hello")
            .to("chunk://subfolder/theme1")
```

In this example the chunk component will look for hello.chtml template in themes folder and for theme1.chtml in themes/subfolder/

**Example 4**

```java
	from("direct:in")
            .to("chunk:subfile_example?themeFolder=folderexample&themeSubfolder=subfolderexample")
```

In this example the chunk component will look for subfile_example.chtml in folderexample/subfolderexample/ folder and not in the default themes folder.

**Example 5**

```java
	from("direct:in")
             .to("chunk:subfile_example?themeFolder=folderexample&themeSubfolder=subfolderexample&extension=file")
```

In this example the chunk component will look for subfile_example.file (not .chtml or .cxml) in folderexample/subfolderexample/ folder and not in the default themes folder.