StandardClassappendTagProcessor.java

/*
 * =============================================================================
 * 
 *   Copyright (c) 2011-2016, The THYMELEAF team (http://www.thymeleaf.org)
 * 
 *   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 org.thymeleaf.standard.processor;

import org.thymeleaf.context.ITemplateContext;
import org.thymeleaf.engine.AttributeDefinition;
import org.thymeleaf.engine.AttributeDefinitions;
import org.thymeleaf.engine.AttributeName;
import org.thymeleaf.engine.IAttributeDefinitionsAware;
import org.thymeleaf.model.IProcessableElementTag;
import org.thymeleaf.processor.element.IElementTagStructureHandler;
import org.thymeleaf.standard.util.StandardProcessorUtils;
import org.thymeleaf.templatemode.TemplateMode;
import org.thymeleaf.util.Validate;
import org.unbescape.html.HtmlEscape;

/**
 *
 * @author Daniel Fernández
 *
 * @since 3.0.0
 *
 */
public final class StandardClassappendTagProcessor
        extends AbstractStandardExpressionAttributeTagProcessor
        implements IAttributeDefinitionsAware {

    public static final int PRECEDENCE = 1100;
    public static final String ATTR_NAME = "classappend";
    public static final String TARGET_ATTR_NAME = "class";

    private static final TemplateMode TEMPLATE_MODE = TemplateMode.HTML;

    private AttributeDefinition targetAttributeDefinition;




    public StandardClassappendTagProcessor(final String dialectPrefix) {
        super(TEMPLATE_MODE, dialectPrefix, ATTR_NAME, PRECEDENCE, true);
    }




    public void setAttributeDefinitions(final AttributeDefinitions attributeDefinitions) {
        Validate.notNull(attributeDefinitions, "Attribute Definitions cannot be null");
        // We precompute the AttributeDefinition of the target attribute in order to being able to use much
        // faster methods for setting/replacing attributes on the ElementAttributes implementation
        this.targetAttributeDefinition = attributeDefinitions.forName(TEMPLATE_MODE, TARGET_ATTR_NAME);
    }




    @Override
    protected final void doProcess(
            final ITemplateContext context,
            final IProcessableElementTag tag,
            final AttributeName attributeName, final String attributeValue,
            final Object expressionResult,
            final IElementTagStructureHandler structureHandler) {

        String newAttributeValue = HtmlEscape.escapeHtml4Xml(expressionResult == null ? null : expressionResult.toString());

        // If we are not adding anything, we'll just leave it untouched
        if (newAttributeValue != null && newAttributeValue.length() > 0) {

            final AttributeName targetAttributeName = this.targetAttributeDefinition.getAttributeName();

            if (tag.hasAttribute(targetAttributeName)) {
                final String currentValue = tag.getAttributeValue(targetAttributeName);
                if (currentValue.length() > 0) {
                    newAttributeValue = currentValue + ' ' + newAttributeValue;
                }
            }

            StandardProcessorUtils.setAttribute(structureHandler, this.targetAttributeDefinition, TARGET_ATTR_NAME, newAttributeValue);

        }

    }


}