Velocity, different template paths

Question

Does anyone know if it is possible to get templates from different paths with velocity? After initialization Velocity refuses to change the "file.resource.loader.path".

This is my code:

public Generator(){         
    Properties p = new Properties();
        p.setProperty("resource.loader", "file");
        p.setProperty("file.resource.loader.class", "org.apache.velocity.runtime.resource.loader.FileResourceLoader");
        p.setProperty("file.resource.loader.path", "");

    Velocity.init(p);
}

The templates can be located in different locations ( the user can select one with a file dialog ). So I have this code upon fetching the template out of velocity

private Template fetch (String templatePath) {
    out_println("Initializing Velocity core...");
    int end = templatePath.lastIndexOf(File.separator); 

    Properties p = new Properties();
        p.setProperty("file.resource.loader.path", templatePath.substring(0, end));
    Velocity.init(p);

    return Velocity.getTemplate(templatePath.substring(end+1));
}

This is not working. It seems that once Velocity is initialized it can't be reset with different properties. Any suggestions on how to solve this problem?

Possible Program flow:

1. User selects group that needs to be filled into the template
2. User selects a template to use (can be located anywhere on the hdd)
3. User presses generate

Answer 1

Velocity can be used in two ways: the singleton model or the separate instance model. You are currently using the singleton model in which only one instance of the Velocity engine in the JVM is allowed.

Instead, you should use the separate instance model which allows you to create multiple instances of Velocity in the same JVM in order to support different template directories.

VelocityEngine ve = new VelocityEngine();
ve.setProperty(RuntimeConstants.FILE_RESOURCE_LOADER_PATH, "path/to/templates");
ve.init();
Template t = ve.getTemplate("foo.vm");