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XML/XHTML/HTML5 template engine for Java
/*
* =============================================================================
*
* Copyright (c) 2011-2014, 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 java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.thymeleaf.Arguments;
import org.thymeleaf.Configuration;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.context.IProcessingContext;
import org.thymeleaf.exceptions.TemplateProcessingException;
import org.thymeleaf.util.MessageResolutionUtils;
import org.thymeleaf.util.StringUtils;
import org.thymeleaf.util.Validate;
/**
*
* @author Daniel Fernández
*
* @since 1.1
*
*/
public final class MessageExpression extends SimpleExpression {
private static final Logger logger = LoggerFactory.getLogger(MessageExpression.class);
private static final long serialVersionUID = 8394399541792390735L;
static final char SELECTOR = '#';
private static final char PARAMS_START_CHAR = '(';
private static final char PARAMS_END_CHAR = ')';
private static final Pattern MSG_PATTERN =
Pattern.compile("^\\s*\\#\\{(.+?)\\}\\s*$", Pattern.DOTALL);
private final IStandardExpression base;
private final ExpressionSequence parameters;
public MessageExpression(final IStandardExpression base, final ExpressionSequence parameters) {
super();
Validate.notNull(base, "Base cannot be null");
this.base = base;
this.parameters = parameters;
}
public IStandardExpression getBase() {
return this.base;
}
public ExpressionSequence getParameters() {
return this.parameters;
}
public boolean hasParameters() {
return this.parameters != null && this.parameters.size() > 0;
}
@Override
public String getStringRepresentation() {
final StringBuilder sb = new StringBuilder();
sb.append(SELECTOR);
sb.append(SimpleExpression.EXPRESSION_START_CHAR);
sb.append(this.base);
if (hasParameters()) {
sb.append(PARAMS_START_CHAR);
sb.append(this.parameters.getStringRepresentation());
sb.append(PARAMS_END_CHAR);
}
sb.append(SimpleExpression.EXPRESSION_END_CHAR);
return sb.toString();
}
static MessageExpression parseMessage(final String input) {
final Matcher matcher = MSG_PATTERN.matcher(input);
if (!matcher.matches()) {
return null;
}
final String content = matcher.group(1);
if (StringUtils.isEmptyOrWhitespace(content)) {
return null;
}
final String trimmedInput = content.trim();
if (trimmedInput.endsWith(String.valueOf(PARAMS_END_CHAR))) {
boolean inLiteral = false;
int nestParLevel = 0;
for (int i = trimmedInput.length() - 1; i >= 0; i--) {
final char c = trimmedInput.charAt(i);
if (c == TextLiteralExpression.DELIMITER) {
if (i == 0 || content.charAt(i - 1) != '\\') {
inLiteral = !inLiteral;
}
} else if (c == PARAMS_END_CHAR) {
nestParLevel++;
} else if (c == PARAMS_START_CHAR) {
nestParLevel--;
if (nestParLevel < 0) {
return null;
}
if (nestParLevel == 0) {
if (i == 0) {
return null;
}
final String base = trimmedInput.substring(0, i);
final String parameters = trimmedInput.substring(i + 1, trimmedInput.length() - 1);
final Expression baseExpr = parseDefaultAsLiteral(base);
if (baseExpr == null) {
return null;
}
final ExpressionSequence parametersExprSeq =
ExpressionSequenceUtils.internalParseExpressionSequence(parameters);
if (parametersExprSeq == null) {
return null;
}
return new MessageExpression(baseExpr, parametersExprSeq);
}
}
}
return null;
}
final Expression baseExpr = parseDefaultAsLiteral(trimmedInput);
if (baseExpr == null) {
return null;
}
return new MessageExpression(baseExpr, null);
}
private static Expression parseDefaultAsLiteral(final String input) {
if (StringUtils.isEmptyOrWhitespace(input)) {
return null;
}
final Expression expr = Expression.parse(input);
if (expr == null) {
return Expression.parse(TextLiteralExpression.wrapStringIntoLiteral(input));
}
return expr;
}
static Object executeMessage(final Configuration configuration,
final IProcessingContext processingContext, final MessageExpression expression,
final StandardExpressionExecutionContext expContext) {
if (logger.isTraceEnabled()) {
logger.trace("[THYMELEAF][{}] Evaluating message: \"{}\"", TemplateEngine.threadIndex(), expression.getStringRepresentation());
}
if (!(processingContext instanceof Arguments)) {
throw new TemplateProcessingException(
"Cannot evaluate expression \"" + expression + "\". Message externalization expressions " +
"can only be evaluated in a template-processing environment (as a part of an in-template expression) " +
"where evaluation context is an " + Arguments.class.getClass() + " instance instead of an instance of " +
processingContext.getClass().getName());
}
final Arguments arguments = (Arguments) processingContext;
final IStandardExpression baseExpression = expression.getBase();
Object messageKey = baseExpression.execute(configuration, arguments, expContext);
messageKey = LiteralValue.unwrap(messageKey);
if (messageKey != null && !(messageKey instanceof String)) {
messageKey = messageKey.toString();
}
if (StringUtils.isEmptyOrWhitespace((String)messageKey)) {
throw new TemplateProcessingException(
"Message key for message resolution must be a non-null and non-empty String");
}
final Object[] messageParameters =
new Object[(expression.hasParameters()? expression.getParameters().size() : 0)];
if (expression.hasParameters()) {
int parIndex = 0;
for (final IStandardExpression parameter : expression.getParameters()) {
final Object result = parameter.execute(configuration, arguments, expContext);
messageParameters[parIndex++] = LiteralValue.unwrap(result);
}
}
return MessageResolutionUtils.resolveMessageForTemplate(
arguments, (String)messageKey, messageParameters);
}
}