DefaultWidgetRegistry.java

package com.google.sitebricks.rendering.control;

import com.google.common.collect.MapMaker;
import com.google.inject.Inject;
import com.google.inject.Injector;
import com.google.inject.Singleton;
import com.google.sitebricks.Evaluator;
import com.google.sitebricks.Renderable;
import com.google.sitebricks.compiler.EvaluatorCompiler;
import com.google.sitebricks.compiler.ExpressionCompileException;
import com.google.sitebricks.compiler.Parsing;
import com.google.sitebricks.compiler.RepeatToken;
import com.google.sitebricks.routing.PageBook;
import net.jcip.annotations.ThreadSafe;

import java.util.Map;
import java.util.concurrent.ConcurrentMap;

/**
 * @author Dhanji R. Prasanna (dhanji@gmail.com)
 */
@ThreadSafe
@Singleton
class DefaultWidgetRegistry implements WidgetRegistry {
  public static final String TEXT_WIDGET = "__w:wRawText_Widget";

  private final Injector injector;
  private final Evaluator evaluator;
  private final PageBook pageBook;

  private final ConcurrentMap<String, WidgetWrapper> widgets = new MapMaker().makeMap();

  @Inject
  public DefaultWidgetRegistry(Evaluator evaluator, PageBook pageBook, Injector injector) {
    this.evaluator = evaluator;
    this.pageBook = pageBook;
    this.injector = injector;

    //register core sitebricks controllers.
    addCoreControllers();
  }

  private void addCoreControllers() {
    //TODO make these case sensitive
    add("textfield", TextFieldWidget.class);
    add("repeat", RepeatWidget.class);
    add("showif", ShowIfWidget.class);
    add("choose", ChooseWidget.class);
    add("include", IncludeWidget.class);
    add("decorated", DecorateWidget.class);
    add("errors", ErrorsWidget.class);
  }

  public void add(String key, Class<? extends Renderable> widget) {
    widgets.put(key.toLowerCase().trim(), WidgetWrapper.forWidget(key, widget));
  }

  public boolean isSelfRendering(String widget) {
    WidgetWrapper wrapper = widgets.get(widget);

    if (null == wrapper) {
      throw new NoSuchWidgetException(
          "No widget found matching the name: @"
              + widget + " ; Did you forget to bind your"
              + " widget class using the embed().as() rule?");
    }

    return wrapper.isSelfRendering();
  }


  public RepeatToken parseRepeat(String expression) {
    //parse and convert widget into metadata annotation
    final Map<String, String> bindMap = Parsing.toBindMap(expression);

    //noinspection OverlyComplexAnonymousInnerClass
    return new RepeatToken() {

      public String items() {
        return bindMap.get(RepeatToken.ITEMS);
      }

      public String var() {
        final String var = bindMap.get(RepeatToken.VAR);

        return null != var ? Parsing.stripQuotes(var) : null;
      }

      public String pageVar() {
        final String pageVar = bindMap.get(RepeatToken.PAGE_VAR);

        return null == pageVar ? RepeatToken.DEFAULT_PAGEVAR : pageVar;
      }
    };
  }

  public Renderable headWidget(WidgetChain childsChildren,
                               Map<String, String> attribs, EvaluatorCompiler compiler)
      throws ExpressionCompileException {
    return new HeaderWidget(childsChildren, attribs, compiler);
  }

  public XmlWidget xmlWidget(WidgetChain childsChildren, String elementName,
                             Map<String, String> attribs,
                             EvaluatorCompiler compiler) throws ExpressionCompileException {

    final XmlWidget widget = new XmlWidget(childsChildren, elementName, compiler, attribs);
    injector.injectMembers(widget);

    return widget;
  }

  public Renderable newWidget(String key, String expression, WidgetChain widgetChain,
                              EvaluatorCompiler compiler)
      throws ExpressionCompileException {

    if (!widgets.containsKey(key)) {
      throw new NoSuchWidgetException("No such widget registered (did you add"
          + " it correctly in module setup?): " + key);
    }

    if (TEXT_WIDGET.equals(key))
      return new TextWidget(null, compiler);

    //otherwise construct via reflection (all sitebricks MUST have
    // a constructor with: widgetchain, expression, evaluator; in that order)
    final Renderable widget = widgets
        .get(key)
        .newWidget(widgetChain, expression, evaluator, pageBook);

    //add some injection (some sitebricks require it). It's a bit hacky, maybe we can reimplement some stuff later with @AssistedInject
    injector.injectMembers(widget);

    return widget;
  }

  public Renderable requireWidget(XmlWidget xmlWidget)
      throws ExpressionCompileException {
    return new RequireWidget(xmlWidget);
  }

  public Renderable textWidget(String template, EvaluatorCompiler compiler)
      throws ExpressionCompileException {
    return new TextWidget(template, compiler);
  }

  public Renderable rawTextWidget(String template, EvaluatorCompiler compiler)
      throws ExpressionCompileException {
    return new RawTextWidget(template, compiler);
  }

  @Override
  public Renderable xmlDirectiveWidget(String wholeDeclaration, EvaluatorCompiler evaluatorCompiler)
      throws ExpressionCompileException {
    return new XmlDirectiveWidget(wholeDeclaration, evaluatorCompiler);
  }

  public void addEmbed(String embedAs) {
    add(embedAs, EmbedWidget.class);
  }

  public void addArgument(String callWith) {
    add(callWith, ArgumentWidget.class);
  }
}