nz.net.ultraq.thymeleaf.models.TemplateModelFinder.groovy Maven / Gradle / Ivy

/* 
 * Copyright 2015, Emanuel Rabina (http://www.ultraq.net.nz/)
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package nz.net.ultraq.thymeleaf.models

import nz.net.ultraq.thymeleaf.LayoutDialect

import org.thymeleaf.context.ITemplateContext
import org.thymeleaf.engine.TemplateModel
import org.thymeleaf.standard.expression.FragmentExpression

/**
 * A simple API for retrieving (immutable template) models using Thymeleaf's
 * template manager.
 * 
 * @author Emanuel Rabina
 */
class TemplateModelFinder {

	private final ITemplateContext context

	/**
	 * Constructor, set the template context we're working in.
	 * 
	 * @param context
	 */
	TemplateModelFinder(ITemplateContext context) {

		this.context = context
	}

	/**
	 * Return a model for any arbitrary item in a template.
	 * 
	 * @param templateName
	 * @param selector     A Thymeleaf DOM selector, which in turn is an
	 *                     AttoParser DOM selector.  See the Appendix in the Using
	 *                     Thymeleaf docs for the DOM selector syntax.
	 * @return Model for the selected template and selector.
	 */
	private TemplateModel find(String templateName, String selector = null) {

		return context.configuration.templateManager.parseStandalone(context,
			templateName, selector ? [selector] as Set : null, context.templateMode, true, true)
	}

	/**
	 * Return the model specified by the given fragment expression.
	 * 
	 * @param fragmentExpression
	 * @return Fragment matching the fragment specification.
	 */
	TemplateModel findFragment(FragmentExpression fragmentExpression) {

		def dialectPrefix = context.getPrefixForDialect(LayoutDialect)
		def templateName = fragmentExpression.templateName?.execute(context)?.toString() ?: 'this'
		if (templateName == 'this') {
			templateName = context.templateData.template
		}
		return findFragment(templateName, fragmentExpression.fragmentSelector?.execute(context)?.toString(), dialectPrefix)
	}

	/**
	 * Return the model specified by the template and fragment name parameters.
	 * 
	 * @param templateName
	 * @param fragmentName
	 * @param dialectPrefix
	 * @return Fragment matching the fragment specification.
	 */
	@SuppressWarnings('UnnecessaryGString')
	TemplateModel findFragment(String templateName, String fragmentName = null, String dialectPrefix = null) {

		return find(templateName,

			// Attoparser fragment selector, picks a fragment with layout:fragment="name"
			// or starts with layout:fragment="name( or layout:fragment="name ( plus
			// their data attribute equivalents. See the attoparser API docs for details:
			// http://www.attoparser.org/apidocs/attoparser/2.0.0.RELEASE/org/attoparser/select/package-summary.html
			fragmentName && dialectPrefix ? "//[" +
				"${dialectPrefix}:fragment='${fragmentName}' or " +
				"${dialectPrefix}:fragment^='${fragmentName}(' or " +
				"${dialectPrefix}:fragment^='${fragmentName} (' or " +
				"data-${dialectPrefix}-fragment='${fragmentName}' or " +
				"data-${dialectPrefix}-fragment^='${fragmentName}(' or " +
				"data-${dialectPrefix}-fragment^='${fragmentName} ('" +
			"]" : null
		)
	}

	/**
	 * Return a model for the template specified by the given fragment expression.
	 * 
	 * @param fragmentExpression
	 * @return Template model matching the fragment specification.
	 */
	TemplateModel findTemplate(FragmentExpression fragmentExpression) {

		return find(fragmentExpression.templateName.execute(context).toString())
	}

	/**
	 * Return a model for the template specified by the given template name.
	 * 
	 * @param templateName
	 * @return Template model matching the fragment specification.
	 */
	TemplateModel findTemplate(String templateName) {

		return find(templateName)
	}
}