/*
* Copyright 2010 Google Inc.
*
* 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 com.google.gwt.validation.client;
import com.google.gwt.core.client.GWT;
import com.google.gwt.i18n.shared.GwtLocale;
import com.google.gwt.regexp.shared.MatchResult;
import com.google.gwt.regexp.shared.RegExp;
import java.util.Map;
import javax.validation.MessageInterpolator;
/**
* <strong>EXPERIMENTAL</strong> and subject to change. Do not use this in
* production code.
* <p>
* Base GWT {@link MessageInterpolator}.
*/
abstract class BaseMessageInterpolator implements MessageInterpolator {
// local version because guava is not included.
private static interface Function<F, T> {
T apply(F from);
}
/**
* Regular expression used to do message interpolation.
*/
private static final RegExp MESSAGE_PARAMETER_PATTERN = RegExp.compile(
"(\\{[^\\}]+?\\})", "g");
// Visible for testing
static Function<String, String> createAnnotationReplacer(
final Map<String, Object> map) {
return new Function<String, String>() {
public String apply(String from) {
Object object = map.get(from);
return object == null ? null : object.toString();
}
};
}
private static Function<String, String> createReplacer(
final ValidationMessageResolver messageResolver) {
return new Function<String, String>() {
public String apply(String from) {
Object object = messageResolver.get(from);
return object == null ? null : object.toString();
}
};
}
/**
* Replaces keys using the Default Validation Provider properties.
*/
private final Function<String, String> providerReplacer =
createReplacer((ValidationMessageResolver)
GWT.create(ProviderValidationMessageResolver.class));
/**
* Replaces keys using the Validation User custom properties.
*/
private final Function<String, String> userReplacer;
protected BaseMessageInterpolator(
UserValidationMessagesResolver userValidationMessagesResolver) {
userReplacer = createReplacer(userValidationMessagesResolver);
}
public final String interpolate(String messageTemplate, Context context) {
return gwtInterpolate(messageTemplate, context, null);
}
protected final String gwtInterpolate(String message, Context context,
GwtLocale locale) {
// see Section 4.3.1.1
String resolvedMessage = message;
String step1message;
// TODO(nchalko) Add a safety to make sure this does not loop forever.
do {
do {
step1message = resolvedMessage;
// Step 1 Replace message parameters using custom user messages
// repeat
resolvedMessage = replaceParameters(resolvedMessage, userReplacer);
} while (!step1message.equals(resolvedMessage));
// Step2 Replace message parameter using the default provider messages.
resolvedMessage = replaceParameters(resolvedMessage, providerReplacer);
// Step 3 repeat from step 1 if step 2 made changes.
} while (!step1message.equals(resolvedMessage));
// step 4 resolve annotation attributes
resolvedMessage = replaceParameters(
resolvedMessage,
createAnnotationReplacer(context.getConstraintDescriptor().getAttributes()));
// Remove escapes (4.3.1)
resolvedMessage = resolvedMessage.replace("\\{", "{");
resolvedMessage = resolvedMessage.replace("\\}", "}");
resolvedMessage = resolvedMessage.replace("\\\\", "\\");
return resolvedMessage;
}
protected final String replaceParameters(String message,
Function<String, String> replacer) {
StringBuffer sb = new StringBuffer();
int index = 0;
MatchResult matcher;
while ((matcher = MESSAGE_PARAMETER_PATTERN.exec(message)) != null) {
String matched = matcher.getGroup(0);
sb.append(message.substring(index, matcher.getIndex()));
Object value = replacer.apply(removeCurlyBrace(matched));
sb.append(value == null ? matched : value);
index = MESSAGE_PARAMETER_PATTERN.getLastIndex();
}
if (index < message.length()) {
sb.append(message.substring(index));
}
return sb.toString();
}
private final String removeCurlyBrace(String parameter) {
return parameter.substring(1, parameter.length() - 1);
}
}