nz.net.ultraq.thymeleaf.includes.IncludeProcessor Maven / Gradle / Ivy

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/* 
 * Copyright 2012, 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.includes;

import java.util.List;
import java.util.Map;
import nz.net.ultraq.thymeleaf.fragments.FragmentFinder;
import nz.net.ultraq.thymeleaf.fragments.FragmentMap;
import nz.net.ultraq.thymeleaf.fragments.FragmentMapper;
import org.thymeleaf.Arguments;
import org.thymeleaf.dom.Element;
import org.thymeleaf.dom.Node;
import org.thymeleaf.processor.ProcessorResult;
import org.thymeleaf.processor.attr.AbstractAttrProcessor;

/**
 * Similar to Thymeleaf's th:include, but allows the passing of entire
 * element fragments to the included template. Useful if you have some HTML that
 * you want to reuse, but whose contents are too complex to determine or
 * construct with context variables alone.
 *
 * @author Emanuel Rabina
 */
public class IncludeProcessor extends AbstractAttrProcessor {

    public static final String PROCESSOR_NAME_INCLUDE = "include";

    /**
     * Constructor, sets this processor to work on the 'include' attribute.
     */
    public IncludeProcessor() {
        super(PROCESSOR_NAME_INCLUDE);
    }

    /**
     * Locates the specified page and includes it into the current template.
     *
     * @param arguments
     * @param element
     * @param attributeName
     * @return Result of the processing.
     */
    @Override
    protected ProcessorResult processAttribute(Arguments arguments, Element element, String attributeName) {
        // Locate the page and fragment to include
        List includeFragments = new FragmentFinder(arguments)
                .findFragments(element.getAttributeValue(attributeName));

        // Gather all fragment parts within the include element, scoping them to
        // this element
        Map elementFragments = new FragmentMapper().map(element.getElementChildren());
        FragmentMap.updateForNode(arguments, element, elementFragments);

        // Replace the children of this element with those of the include page
        // fragments.  The 'container' element is copied from how Thymeleaf does
        // it's include processor, which is to maintain internal structures like
        // local variables
        element.clearChildren();
        if (includeFragments != null && !includeFragments.isEmpty()) {
            Element containerElement = new Element("container");
            for (Node includeFragment : includeFragments) {
                containerElement.addChild(includeFragment);
                containerElement.extractChild(includeFragment);
            }
            for (Node extractedChild : containerElement.getChildren()) {
                element.addChild(extractedChild);
            }
        }

        element.removeAttribute(attributeName);
        return ProcessorResult.OK;
    }

    @Override
    public int getPrecedence() {
        return 1;
    }

}