AbstractStandardDoubleAttributeModifierTagProcessor.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 abstract class AbstractStandardDoubleAttributeModifierTagProcessor
            extends AbstractStandardExpressionAttributeTagProcessor
            implements IAttributeDefinitionsAware {


    private final boolean removeIfEmpty;
    private final String attributeOneCompleteName;
    private final String attributeTwoCompleteName;

    private AttributeDefinition attributeOneDefinition;
    private AttributeDefinition attributeTwoDefinition;




    protected AbstractStandardDoubleAttributeModifierTagProcessor(
            final TemplateMode templateMode, final String dialectPrefix, final String attrName,
            final int precedence,
            final String attributeOneCompleteName, final String attributeTwoCompleteName,
            final boolean removeIfEmpty) {

        super(templateMode, dialectPrefix, attrName, precedence, true);

        Validate.notNull(attributeOneCompleteName, "Complete name of attribute one cannot be null");
        Validate.notNull(attributeTwoCompleteName, "Complete name of attribute one cannot be null");

        this.removeIfEmpty = removeIfEmpty;

        this.attributeOneCompleteName = attributeOneCompleteName;
        this.attributeTwoCompleteName = attributeTwoCompleteName;

    }




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




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

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

        // These attributes might be "removable if empty", in which case we would simply remove the target attributes...
        if (this.removeIfEmpty && (newAttributeValue == null || newAttributeValue.length() == 0)) {
            // We are removing the equivalent attribute name, without the prefix...
            structureHandler.removeAttribute(this.attributeOneDefinition.getAttributeName());
            structureHandler.removeAttribute(this.attributeTwoDefinition.getAttributeName());
        } else {
            // We are setting the equivalent attribute name, without the prefix...
            StandardProcessorUtils.setAttribute(structureHandler, this.attributeOneDefinition, this.attributeOneCompleteName, newAttributeValue);
            StandardProcessorUtils.setAttribute(structureHandler, this.attributeTwoDefinition, this.attributeTwoCompleteName, newAttributeValue);
        }

    }


}