First implementation of templates #193
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| * @return the generated string where each parameter is replaced by its value provided in the map | ||
| * @throws TemplateException in case of issues during the string generation, e.g. missing parameter | ||
| */ | ||
| String process(Map<String, String> parameters) throws TemplateException; |
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With a Map<String, String> we can only handle 1 fields level in templates. What happen if a template engine accepts complex objects (${user.address.street} for example)?
| * @return the generated string where each parameter is replaced by its value provided in the map | ||
| * @throws TemplateException in case of issues during the string generation, e.g. missing parameter | ||
| */ | ||
| String process(Map<String, String> parameters) throws TemplateException; |
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With a Map<String, String> as parameter we can only manage 1 level of attributes while most of the template engines support tree values as data-model (cf. https://freemarker.apache.org/docs/dgui_quickstart_datamodel.html).
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Freemarker can process an object for instance (https://freemarker.apache.org/docs/api/freemarker/template/Template.html#process-java.lang.Object-java.io.Writer-), that would be nice to study different template engines to see what they offer but I think this is where we should go
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FreeMarker accepts any kind of objects, like Map<String, Object> or java beans: https://freemarker.apache.org/docs/pgui_quickstart_createdatamodel.html
Velocity accepts a Context object which is a Map like object, see : http://velocity.apache.org/engine/devel/developer-guide.html#the-context
Thymleaf accepts an IContext object: https://www.thymeleaf.org/doc/tutorials/3.0/usingthymeleaf.html#contexts
I would suggest to accept a Object in the interface and each implementation will have to check the actual type.
| public interface Template { | ||
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| /** | ||
| * |
| * Interface to represent a template. | ||
| * A template takes parameters in input and outputs a string. | ||
| */ | ||
| public interface Template { |
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@API Guardian annotation are missing
| /** | ||
| * Internal class used when instantiating a {@link FreeMarkerTemplate} with {@link FreeMarkerEngine#newTemplateFromUrl(String)} | ||
| */ | ||
| public class UrlTemplateLoader extends URLTemplateLoader { |
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I think this class should be package-protected. I don't think developers will touch this class.
| .warn("More than 1 TemplateEngine implementation found in classpath, will use : {}", | ||
| templateEngines.stream().findFirst().get()); | ||
| } | ||
| LoggerFactory.getLogger(TemplateEngine.class).info("TemplateEngine implementation found"); |
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@symphony-thibault I cannot use the Slf4j annotation as it is only valid on classes and enums. This leads to the following error : Failed to load class "org.slf4j.impl.StaticLoggerBinder".
What should I do ? Remove the logs ?
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| private static String getStringFromBuiltInTemplate() throws TemplateException { | ||
| Template template = new FreeMarkerEngine().newBuiltInTemplate("simpleMML"); |
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Do you think we need a enum listing all built-in templates we have? IMHO, it might be more convenient if we write something like: new FreeMarkerEngine().newBuiltInTemplate(BuiltInTemplate.SIMPLE_MML);
WDYT?
| * @return a new {@link Template} instantiated from the provided file | ||
| * @throws TemplateException when template cannot be loaded, e.g. file not accessible | ||
| */ | ||
| Template newTemplateFromFile(String templatePath) throws TemplateException; |
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perhaps we could support URI? and then find out it is a file or the classpath based on it?
file:///root/blah.text classpath://com/symphony/bdk/blah.text
| * @return a new {@link Template} instantiated from the provided url, should be a valid {@link java.net.URL} string. | ||
| * @throws TemplateException when template cannot be loaded, e.g. url not accessible | ||
| */ | ||
| Template newTemplateFromUrl(String url) throws TemplateException; |
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ah we have URL here, would not URI cover everything?
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