What's new in Slice 4.2

Instantiating model objects by path (annotation "Follow")

It's a very common case when you keep a path in some property and you want to build a model based on a resource pointed by this path, e.g. you let authors configure references to some content and this reference is kept in property. To make reading of such referenced models, additional annotation @Follow was introduced - it allows mapper to map a resource by following a path stored under given property. It is possible to use this annotation in conjunction with @Children as well.

Thanks to this you can make your code even cleaner. Check the following code snippets and see how Report

// Now - with @Follow annotation
@SliceResource
public class ReportComponent  {
    @Follow
	@JcrProperty(value = "reportPath") 
	private ReportModel report; // this will build ReportModel based on resource path kept in reportPath property of current resource
	
	public String getReportValue() {
        return reportModel.getValue();
    }
}
// Before
@SliceResource
public class ReportComponent implements InitializableModel {   
    @JcrProperty 
    private String reportPath;
    
    private ReportModel report;
    
    private ModelProvider modelProvider;
    
    @Inject
    public ReportComponent(ModelProvider modelProvider) {
        this.modelProvider = modelProvider
    }
    
    @Override
    public void afterCreated() {
        report = modelProvider.get(ReportModel.class, reportPath);
    }
    
    public String getReportValue() {
        return reportModel.getValue();
    }
}

Static declaration of model class

Since Slice 4.2 you can declare which model class your component should use in a component definition. If you do this, you can simplify your JSP file and omit the slice:model tag. Slice will provide an expected model through JSP bindings and set a model object for JSP use.

For example, we can define the following component's definition:

<?xml version="1.0" encoding="UTF-8"?>
<jcr:root xmlns:slice="http://www.cognifide.com/slice/1.0" xmlns:sling="http://sling.apache.org/jcr/sling/1.0"  xmlns:cq="http://www.day.com/jcr/cq/1.0" xmlns:jcr="http://www.jcp.org/jcr/1.0"
    jcr:primaryType="cq:Component"
    jcr:title="Rich Text"
    slice:model="com.example.RichTextModel"/>

In such case, we don't need to explicitly declare model in JSP file - it will be available out of the box, in a JSP bindings object, like in the example below:

<%@page pageEncoding="UTF-8" contentType="text/html; charset=UTF-8"%>
<%@include file="/libs/foundation/global.jsp"%>

Richtext content: ${bindings.model.text}

To simplify the code even more, you can put <slice:defineObjects/> somewhere in global.jsp include - it allows you to avoid "bindings" part, so above code, can be simplified as follows:

<%@page pageEncoding="UTF-8" contentType="text/html; charset=UTF-8"%>
<%@include file="/libs/foundation/global.jsp"%>
<slice:defineObjects/>

Richtext content: ${model.text}

This feature may also be useful for some more general solutions, as you can use newly-introduced method of ModelProvider: get(Resource) - this will return appropriate mapped object without specifying its class on code level.

Throwing exception if fail to create injector

If for whatever reason, an injector of your application cannot be created (most likely due to some incorrect Guice bindings) you'd probably expect the Activator of your app to fail as well making your application unavailable and preventing hard-to-spot-and-debug runtime issues. We've just added this feature to InjectorRunner. If injector has failed on starting, InjectorRunner will throw BundleException to force your Activator failure as well.

Improved support for updated bundles

If your application consists of couple of bundles you may have experienced an issue while updating only one of them. Slice had not seen this update and wasn't able to map objects from this bundle correctly. In Slice 4.2 we fixed this important problem. Therefore you can easily update a selected bundle and Slice will be informed about this change providing correctly mapped objects.

Upgraded dependencies

Since Slice 4.2, it is possible to use Lambda expressions (Java 8) thanks to upgraded ASM dependency. Slice has also started to use Peaberry 1.3, which supports a Dynamic Configuration feature.

Semantic versioning approach

We've introduce full semantic versioning to Slice, so you can be sure that all interfaces are semantically versioned and you can upgrade safely with each minor release.

Bug fixing

Slice 4.2.0 brings also fixes for some minor bugs. You can find full list in release notes.