Class HtmlView

htmlflow-core/src/main/java/htmlflow/HtmlView.java:37–168

Dynamic views can be bound to a Model object. @param Type of the model rendered with this view. @author Miguel Gamboa, Luís Duare

 * @author Miguel Gamboa, Luís Duare
 */
public class HtmlView<M> extends HtmlPage {

    /** Function that consumes an HtmlView to produce HTML elements. */
    protected final HtmlTemplate template;

    /**
     * This field is like a union with the threadLocalVisitor, being used alternatively. For non
     * thread safe scenarios Visitors maybe shared concurrently by multiple threads. On the
     * other-hand, in thread-safe scenarios each thread must have its own visitor to emit HTML to the
     * output, and we use the threadLocalVisitor field instead.
     */
    private final HtmlVisitor visitor;

    /**
     * This issue is regarding ThreadLocal variables that are supposed to be garbage collected. The
     * given example deals with a static field of ThreadLocal which persists beyond an instance. In
     * this case the ThreadLocal is hold in an instance field and should stay with all thread local
     * instances during its entire life cycle.
     */
    @SuppressWarnings("squid:S5164")
    private final ThreadLocal<HtmlVisitor> threadLocalVisitor;

    protected final Supplier<HtmlVisitor> visitorSupplier;
    protected final boolean threadSafe;

    /** Auxiliary constructor used by clone(). */
    HtmlView(
        Supplier<HtmlVisitor> visitorSupplier,
        HtmlTemplate template,
        boolean threadSafe
    ) {
        this.visitorSupplier = visitorSupplier;
        this.template = template;
        this.threadSafe = threadSafe;
        if (threadSafe) {
            this.visitor = null;
            this.threadLocalVisitor = ThreadLocal.withInitial(visitorSupplier);
        } else {
            this.visitor = visitorSupplier.get();
            this.threadLocalVisitor = null;
        }
    }

    public final Html<HtmlPage> html() {
        this.getVisitor().write(HEADER);
        return new Html<>(this);
    }

    public HtmlView<M> threadSafe() {
        return clone(visitorSupplier, true);
    }

    @Override
    public HtmlVisitor getVisitor() {
        return threadSafe ? threadLocalVisitor.get() : visitor;
    }

    public HtmlView<M> setOut(Appendable out) {