pl.chilldev.web.faces.context.FacesPageMetaModelResolver Maven / Gradle / Ivy

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/**
 * This file is part of the ChillDev-Web.
 *
 * @license http://mit-license.org/ The MIT license
 * @copyright 2014 - 2015 © by Rafał Wrzeszcz - Wrzasq.pl.
 */

package pl.chilldev.web.faces.context;

import javax.faces.view.facelets.FaceletContext;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import pl.chilldev.web.core.markup.Generator;
import pl.chilldev.web.core.page.PageMetaModel;

/**
 * Resolves page meta model from Facelets context attribute.
 */
public class FacesPageMetaModelResolver implements PageMetaModelResolver
{
    /**
     * Default Facelets attribute key for storing current page model.
     */
    public static final String ATTRIBUTE_NAME_DEFAULT = "pl.chilldev.web.core.page.PageMetaModel";

    /**
     * Logger.
     */
    private Logger logger = LoggerFactory.getLogger(FacesPageMetaModelResolver.class);

    /**
     * Storage attribute name.
     */
    private String attribute;

    /**
     * Markup generator.
     */
    private Generator generator;

    /**
     * Initializes resolver for given attribute name and with given markup generator.
     *
     * @param attribute Attribute name.
     * @param generator Markup generator.
     */
    public FacesPageMetaModelResolver(String attribute, Generator generator)
    {
        this.attribute = attribute;
        this.generator = generator;
    }

    /**
     * Initializes resolver for given attribute name.
     *
     * @param attribute Attribute name.
     */
    public FacesPageMetaModelResolver(String attribute)
    {
        this(attribute, Generator.DEFAULT_GENERATOR);
    }

    /**
     * Initializes resolver with specified markup generator.
     *
     * @param generator Markup generator.
     */
    public FacesPageMetaModelResolver(Generator generator)
    {
        this(FacesPageMetaModelResolver.ATTRIBUTE_NAME_DEFAULT, generator);
    }

    /**
     * Initializes resolver for default attribute name with default markup generator.
     */
    public FacesPageMetaModelResolver()
    {
        this(FacesPageMetaModelResolver.ATTRIBUTE_NAME_DEFAULT, Generator.DEFAULT_GENERATOR);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public PageMetaModel getPageMetaModel(FaceletContext context)
        throws
            PageMetaModelContextException
    {
        Object value = context.getAttribute(this.attribute);
        PageMetaModel page;

        if (value == null) {
            // initialize new model
            this.logger.debug(
                "Attribtue \"{}\" not found in Facelets context, initializing new page model.",
                this.attribute
            );
            page = this.createPageMetaModel();
            context.setAttribute(this.attribute, page);
        } else if (value instanceof PageMetaModel) {
            // cast existing model
            this.logger.debug("Attribtue \"{}\" found in Facelets context.", this.attribute);
            page = (PageMetaModel) value;
        } else {
            this.logger.error(
                "Attribtue \"{}\" found in Facelets context had type {}.",
                this.attribute,
                value.getClass()
            );
            throw new PageMetaModelContextException(
                String.format(
                    "Attribute \"%s\" in current Facelets context is of type %s.",
                    this.attribute,
                    value.getClass()
                )
            );
        }

        return page;
    }

    /**
     * Initializes new meta model.
     *
     * @return Newly created meta model.
     */
    private PageMetaModel createPageMetaModel()
    {
        return new PageMetaModel(this.generator);
    }
}