groovy.text.markup.TagLibAdapter.groovy Maven / Gradle / Ivy

/*
 * Copyright 2003-2014 the original author or authors.
 *
 * 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 groovy.text.markup

/**
 * Adapts Grails taglibs for use in the template engine. An adapter may be created like this:
 *
 *  *     def model = [:]
 *     def tpl = template.make(model)
 *     model.g = new TagLibAdapter(tpl)
 *     model.g.registerTagLib(SimpleTagLib)
 * 
 *
 * where SimpleTagLib is:
 *
 *  *     class SimpleTagLib {
 *        def emoticon = { attrs, body ->
 *            out << body() << (attrs.happy == 'true' ? " :-)" : " :-(")
 *        }
 *     }
 * 
 *
 * Then it can be used inside a template like this:
 *
 *  *     g.emoticon(happy:'true') { 'Hi John' }
 * 
 *
 * Performance-wise, it would be better to reimplement the taglib, but this makes it easier to reuse
 * exisiting code.
 *
 * @author Cédric Champeau
 */
class TagLibAdapter {
    private final BaseTemplate template
    private final List