UIComponentTagSupport.java

package net.java.dev.weblets.demo.taglib;

import java.util.Map;

import javax.faces.application.Application;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.el.MethodBinding;
import javax.faces.el.ValueBinding;
import javax.faces.webapp.UIComponentTag;

/**
 * UIComponentTagSupport provides common helper methods for
 * JavaServer Faces UIComponent tag handlers.
 */
abstract public class UIComponentTagSupport extends UIComponentTag
{
  /**
   * Sets a component string property as a value binding, or string literal.
   *
   * @param component  the Faces component
   * @param attrName   the attribute name
   * @param value      the attribute value
   */
  protected void setStringProperty(
    UIComponent component,
    String      attrName,
    String      value)
  {
    if (value == null)
      return;

    if (isValueReference(value))
    {
      component.setValueBinding(attrName, createValueBinding(value));
    }
    else
    {
      component.getAttributes().put(attrName, value);
    }
  }

  /**
   * Sets a component boolean property as a value binding, or boolean literal.
   *
   * @param component  the Faces component
   * @param attrName   the attribute name
   * @param value      the attribute value
   */
  protected void setBooleanProperty(
    UIComponent component,
    String      attrName,
    String      value)
  {
    if (value == null)
      return;

    if (isValueReference(value))
    {
      component.setValueBinding(attrName, createValueBinding(value));
    }
    else
    {
      component.getAttributes().put(attrName, Boolean.valueOf(value));
    }
  }

  /**
   * Sets a component property as a value binding.
   *
   * @param component  the Faces component
   * @param attrName   the attribute name
   * @param value      the attribute value
   */
  protected void setValueBindingProperty(
    UIComponent component,
    String      attrName,
    String      value)
  {
    if (value == null)
      return;

    component.setValueBinding(attrName, createValueBinding(value));
  }

  /**
   * Sets a component property as a method binding.
   *
   * @param component  the Faces component
   * @param attrName   the attribute name
   * @param value      the attribute value
   * @param signature  the method signature
   */
  protected void setMethodBindingProperty(
    UIComponent component,
    String      attrName,
    String      value,
    Class[]     signature)
  {
    if (value == null)
      return;

    Map attrs = component.getAttributes();
    attrs.put(attrName, createMethodBinding(value, signature));
  }

  /**
   * Returns a ValueBinding for the string value.
   *
   * @param value  the attribute string value
   *
   * @return  a parsed ValueBinding
   */
  protected ValueBinding createValueBinding(
    String value)
  {
    FacesContext context = FacesContext.getCurrentInstance();
    Application application = context.getApplication();
    return application.createValueBinding(value);
  }

  /**
   * Returns a MethodBinding for the string value.
   *
   * @param value      the attribute string value
   * @param signature  the method binding signature
   *
   * @return  a parsed MethodBinding
   */
  protected MethodBinding createMethodBinding(
    String  value,
    Class[] signature)
  {
    FacesContext context = FacesContext.getCurrentInstance();
    Application application = context.getApplication();
    return application.createMethodBinding(value, signature);
  }
}