nz.net.ultraq.thymeleaf.fragments.mergers.AttributeMerger Maven / Gradle / Ivy

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/*
 * 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.fragments.mergers;

import nz.net.ultraq.thymeleaf.fragments.FragmentMerger;
import nz.net.ultraq.thymeleaf.internal.MetaClass;
import org.thymeleaf.dom.Attribute;
import org.thymeleaf.dom.Element;
import org.thymeleaf.standard.StandardDialect;
import org.thymeleaf.standard.processor.attr.StandardWithAttrProcessor;

import static nz.net.ultraq.thymeleaf.LayoutDialect.DIALECT_PREFIX_LAYOUT;
import static nz.net.ultraq.thymeleaf.fragments.FragmentProcessor.PROCESSOR_NAME_FRAGMENT;

/**
 * Merges a source element's attributes into a target element.
 *
 * @author Emanuel Rabina
 */
public class AttributeMerger implements FragmentMerger {

    /**
     * Merge source element attributes into a target element, overwriting those
     * attributes found in the target with those from the source.
     *
     * @param sourceElement
     * @param targetElement
     */
    @Override
    public void merge(Element targetElement, Element sourceElement) {

        if (sourceElement == null || targetElement == null) {
            return;
        }

        // Exclude the copying of fragment attributes
        for (Attribute sourceAttribute : sourceElement.getAttributeMap().values()) {
            if (MetaClass.equalsName(sourceAttribute, DIALECT_PREFIX_LAYOUT, PROCESSOR_NAME_FRAGMENT)) {
                continue;
            }
            // Merge th:with attributes
            if (MetaClass.equalsName(sourceAttribute, StandardDialect.PREFIX, StandardWithAttrProcessor.ATTR_NAME)) {
                String mergedWithValue = new VariableDeclarationMerger().merge(sourceAttribute.getValue(),
                        MetaClass.getAttributeValue(targetElement, StandardDialect.PREFIX, StandardWithAttrProcessor.ATTR_NAME));
                targetElement.setAttribute(StandardDialect.PREFIX + ":" + StandardWithAttrProcessor.ATTR_NAME, mergedWithValue);
            } else { // Copy every other attribute straight
                targetElement.setAttribute(sourceAttribute.getOriginalName(), sourceAttribute.getValue());
            }
        }
    }

}