// $Id: ResourceBundleMessageInterpolator.java 19777 2010-06-21 13:35:31Z hardy.ferentschik $
/*
* JBoss, Home of Professional Open Source
* Copyright 2009, Red Hat, Inc. and/or its affiliates, and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* 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.hibernate.validator.messageinterpolation;
import java.util.Locale;
import java.util.Map;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
import java.util.WeakHashMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.validation.MessageInterpolator;
import org.hibernate.validator.resourceloading.PlatformResourceBundleLocator;
import org.hibernate.validator.resourceloading.ResourceBundleLocator;
/**
* Resource bundle backed message interpolator.
*
* @author Emmanuel Bernard
* @author Hardy Ferentschik
* @author Gunnar Morling
*/
public class ResourceBundleMessageInterpolator implements MessageInterpolator {
/**
* The name of the default message bundle.
*/
public static final String DEFAULT_VALIDATION_MESSAGES = "org.hibernate.validator.ValidationMessages";
/**
* The name of the user-provided message bundle as defined in the specification.
*/
public static final String USER_VALIDATION_MESSAGES = "ValidationMessages";
/**
* Regular expression used to do message interpolation.
*/
private static final Pattern MESSAGE_PARAMETER_PATTERN = Pattern.compile( "(\\{[^\\}]+?\\})" );
/**
* The default locale for the current user.
*/
private final Locale defaultLocale;
/**
* Loads user-specified resource bundles.
*/
private final ResourceBundleLocator userResourceBundleLocator;
/**
* Loads built-in resource bundles.
*/
private final ResourceBundleLocator defaultResourceBundleLocator;
/**
* Step 1-3 of message interpolation can be cached. We do this in this map.
*/
private final Map<LocalisedMessage, String> resolvedMessages = new WeakHashMap<LocalisedMessage, String>();
/**
* Flag indicating whether this interpolator should chance some of the interpolation steps.
*/
private final boolean cacheMessages;
public ResourceBundleMessageInterpolator() {
this( null );
}
public ResourceBundleMessageInterpolator(ResourceBundleLocator userResourceBundleLocator) {
this( userResourceBundleLocator, true );
}
public ResourceBundleMessageInterpolator(ResourceBundleLocator userResourceBundleLocator, boolean cacheMessages) {
defaultLocale = Locale.getDefault();
if ( userResourceBundleLocator == null ) {
this.userResourceBundleLocator = new PlatformResourceBundleLocator( USER_VALIDATION_MESSAGES );
}
else {
this.userResourceBundleLocator = userResourceBundleLocator;
}
this.defaultResourceBundleLocator = new PlatformResourceBundleLocator( DEFAULT_VALIDATION_MESSAGES );
this.cacheMessages = cacheMessages;
}
public String interpolate(String message, Context context) {
// probably no need for caching, but it could be done by parameters since the map
// is immutable and uniquely built per Validation definition, the comparison has to be based on == and not equals though
return interpolateMessage( message, context.getConstraintDescriptor().getAttributes(), defaultLocale );
}
public String interpolate(String message, Context context, Locale locale) {
return interpolateMessage( message, context.getConstraintDescriptor().getAttributes(), locale );
}
/**
* Runs the message interpolation according to algorithm specified in JSR 303.
* <br/>
* Note:
* <br/>
* Look-ups in user bundles is recursive whereas look-ups in default bundle are not!
*
* @param message the message to interpolate
* @param annotationParameters the parameters of the annotation for which to interpolate this message
* @param locale the {@code Locale} to use for the resource bundle.
*
* @return the interpolated message.
*/
private String interpolateMessage(String message, Map<String, Object> annotationParameters, Locale locale) {
LocalisedMessage localisedMessage = new LocalisedMessage( message, locale );
String resolvedMessage = null;
if ( cacheMessages ) {
resolvedMessage = resolvedMessages.get( localisedMessage );
}
// if the message is not already in the cache we have to run step 1-3 of the message resolution
if ( resolvedMessage == null ) {
ResourceBundle userResourceBundle = userResourceBundleLocator
.getResourceBundle( locale );
ResourceBundle defaultResourceBundle = defaultResourceBundleLocator
.getResourceBundle( locale );
String userBundleResolvedMessage;
resolvedMessage = message;
boolean evaluatedDefaultBundleOnce = false;
do {
// search the user bundle recursive (step1)
userBundleResolvedMessage = replaceVariables(
resolvedMessage, userResourceBundle, locale, true
);
// exit condition - we have at least tried to validate against the default bundle and there was no
// further replacements
if ( evaluatedDefaultBundleOnce
&& !hasReplacementTakenPlace( userBundleResolvedMessage, resolvedMessage ) ) {
break;
}
// search the default bundle non recursive (step2)
resolvedMessage = replaceVariables( userBundleResolvedMessage, defaultResourceBundle, locale, false );
evaluatedDefaultBundleOnce = true;
if ( cacheMessages ) {
resolvedMessages.put( localisedMessage, resolvedMessage );
}
} while ( true );
}
// resolve annotation attributes (step 4)
resolvedMessage = replaceAnnotationAttributes( resolvedMessage, annotationParameters );
// last but not least we have to take care of escaped literals
resolvedMessage = resolvedMessage.replace( "\\{", "{" );
resolvedMessage = resolvedMessage.replace( "\\}", "}" );
resolvedMessage = resolvedMessage.replace( "\\\\", "\\" );
return resolvedMessage;
}
private boolean hasReplacementTakenPlace(String origMessage, String newMessage) {
return !origMessage.equals( newMessage );
}
private String replaceVariables(String message, ResourceBundle bundle, Locale locale, boolean recurse) {
Matcher matcher = MESSAGE_PARAMETER_PATTERN.matcher( message );
StringBuffer sb = new StringBuffer();
String resolvedParameterValue;
while ( matcher.find() ) {
String parameter = matcher.group( 1 );
resolvedParameterValue = resolveParameter(
parameter, bundle, locale, recurse
);
matcher.appendReplacement( sb, escapeMetaCharacters( resolvedParameterValue ) );
}
matcher.appendTail( sb );
return sb.toString();
}
private String replaceAnnotationAttributes(String message, Map<String, Object> annotationParameters) {
Matcher matcher = MESSAGE_PARAMETER_PATTERN.matcher( message );
StringBuffer sb = new StringBuffer();
while ( matcher.find() ) {
String resolvedParameterValue;
String parameter = matcher.group( 1 );
Object variable = annotationParameters.get( removeCurlyBrace( parameter ) );
if ( variable != null ) {
resolvedParameterValue = escapeMetaCharacters( variable.toString() );
}
else {
resolvedParameterValue = parameter;
}
matcher.appendReplacement( sb, resolvedParameterValue );
}
matcher.appendTail( sb );
return sb.toString();
}
private String resolveParameter(String parameterName, ResourceBundle bundle, Locale locale, boolean recurse) {
String parameterValue;
try {
if ( bundle != null ) {
parameterValue = bundle.getString( removeCurlyBrace( parameterName ) );
if ( recurse ) {
parameterValue = replaceVariables( parameterValue, bundle, locale, recurse );
}
}
else {
parameterValue = parameterName;
}
}
catch ( MissingResourceException e ) {
// return parameter itself
parameterValue = parameterName;
}
return parameterValue;
}
private String removeCurlyBrace(String parameter) {
return parameter.substring( 1, parameter.length() - 1 );
}
/**
* @param s The string in which to replace the meta characters '$' and '\'.
*
* @return A string where meta characters relevant for {@link Matcher#appendReplacement} are escaped.
*/
private String escapeMetaCharacters(String s) {
String escapedString = s.replace( "\\", "\\\\" );
escapedString = escapedString.replace( "$", "\\$" );
return escapedString;
}
private static class LocalisedMessage {
private final String message;
private final Locale locale;
LocalisedMessage(String message, Locale locale) {
this.message = message;
this.locale = locale;
}
@Override
public boolean equals(Object o) {
if ( this == o ) {
return true;
}
if ( o == null || getClass() != o.getClass() ) {
return false;
}
LocalisedMessage that = ( LocalisedMessage ) o;
if ( locale != null ? !locale.equals( that.locale ) : that.locale != null ) {
return false;
}
if ( message != null ? !message.equals( that.message ) : that.message != null ) {
return false;
}
return true;
}
@Override
public int hashCode() {
int result = message != null ? message.hashCode() : 0;
result = 31 * result + ( locale != null ? locale.hashCode() : 0 );
return result;
}
}
}