/*
* =============================================================================
*
* 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.expression;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.context.IExpressionContext;
/**
* <p>
* NO-OP (No Operation) token (Thymeleaf Standard Expressions)
* </p>
*
* @author Daniel Fernández
* @since 3.0.0
*/
public final class NoOpTokenExpression extends Token {
private static final Logger logger = LoggerFactory.getLogger(NoOpTokenExpression.class);
private static final long serialVersionUID = -5180150929940011L;
private static final NoOpTokenExpression SINGLETON = new NoOpTokenExpression();
public NoOpTokenExpression() {
super(null);
}
@Override
public String getStringRepresentation() {
return "_";
}
static NoOpTokenExpression parseNoOpTokenExpression(final String input) {
if (input.length() == 1 && input.charAt(0) == '_') {
return SINGLETON;
}
return null;
}
static Object executeNoOpTokenExpression(
final IExpressionContext context,
final NoOpTokenExpression expression,
final StandardExpressionExecutionContext expContext) {
if (logger.isTraceEnabled()) {
logger.trace("[THYMELEAF][{}] Evaluating no-op token: \"{}\"", TemplateEngine.threadIndex(), expression.getStringRepresentation());
}
return NoOpToken.VALUE;
}
}