/*
* Copyright 2002-2016 the original author or authors.
*
* 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.springframework.validation;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import org.springframework.util.StringUtils;
/**
* Default implementation of the {@link MessageCodesResolver} interface.
*
* <p>Will create two message codes for an object error, in the following order (when
* using the {@link Format#PREFIX_ERROR_CODE prefixed}
* {@link #setMessageCodeFormatter(MessageCodeFormatter) formatter}):
* <ul>
* <li>1.: code + "." + object name
* <li>2.: code
* </ul>
*
* <p>Will create four message codes for a field specification, in the following order:
* <ul>
* <li>1.: code + "." + object name + "." + field
* <li>2.: code + "." + field
* <li>3.: code + "." + field type
* <li>4.: code
* </ul>
*
* <p>For example, in case of code "typeMismatch", object name "user", field "age":
* <ul>
* <li>1. try "typeMismatch.user.age"
* <li>2. try "typeMismatch.age"
* <li>3. try "typeMismatch.int"
* <li>4. try "typeMismatch"
* </ul>
*
* <p>This resolution algorithm thus can be leveraged for example to show
* specific messages for binding errors like "required" and "typeMismatch":
* <ul>
* <li>at the object + field level ("age" field, but only on "user");
* <li>at the field level (all "age" fields, no matter which object name);
* <li>or at the general level (all fields, on any object).
* </ul>
*
* <p>In case of array, {@link List} or {@link java.util.Map} properties,
* both codes for specific elements and for the whole collection are
* generated. Assuming a field "name" of an array "groups" in object "user":
* <ul>
* <li>1. try "typeMismatch.user.groups[0].name"
* <li>2. try "typeMismatch.user.groups.name"
* <li>3. try "typeMismatch.groups[0].name"
* <li>4. try "typeMismatch.groups.name"
* <li>5. try "typeMismatch.name"
* <li>6. try "typeMismatch.java.lang.String"
* <li>7. try "typeMismatch"
* </ul>
*
* <p>By default the {@code errorCode}s will be placed at the beginning of constructed
* message strings. The {@link #setMessageCodeFormatter(MessageCodeFormatter)
* messageCodeFormatter} property can be used to specify an alternative concatenation
* {@link MessageCodeFormatter format}.
*
* <p>In order to group all codes into a specific category within your resource bundles,
* e.g. "validation.typeMismatch.name" instead of the default "typeMismatch.name",
* consider specifying a {@link #setPrefix prefix} to be applied.
*
* @author Juergen Hoeller
* @author Phillip Webb
* @author Chris Beams
* @since 1.0.1
*/
@SuppressWarnings("serial")
public class DefaultMessageCodesResolver implements MessageCodesResolver, Serializable {
/**
* The separator that this implementation uses when resolving message codes.
*/
public static final String CODE_SEPARATOR = ".";
private static final MessageCodeFormatter DEFAULT_FORMATTER = Format.PREFIX_ERROR_CODE;
private String prefix = "";
private MessageCodeFormatter formatter = DEFAULT_FORMATTER;
/**
* Specify a prefix to be applied to any code built by this resolver.
* <p>Default is none. Specify, for example, "validation." to get
* error codes like "validation.typeMismatch.name".
*/
public void setPrefix(String prefix) {
this.prefix = (prefix != null ? prefix : "");
}
/**
* Specify the format for message codes built by this resolver.
* <p>The default is {@link Format#PREFIX_ERROR_CODE}.
* @since 3.2
* @see Format
*/
public void setMessageCodeFormatter(MessageCodeFormatter formatter) {
this.formatter = (formatter == null ? DEFAULT_FORMATTER : formatter);
}
/**
* Return the prefix to be applied to any code built by this resolver.
* <p>Returns an empty String in case of no prefix.
*/
protected String getPrefix() {
return this.prefix;
}
@Override
public String[] resolveMessageCodes(String errorCode, String objectName) {
return resolveMessageCodes(errorCode, objectName, "", null);
}
/**
* Build the code list for the given code and field: an
* object/field-specific code, a field-specific code, a plain error code.
* <p>Arrays, Lists and Maps are resolved both for specific elements and
* the whole collection.
* <p>See the {@link DefaultMessageCodesResolver class level Javadoc} for
* details on the generated codes.
* @return the list of codes
*/
@Override
public String[] resolveMessageCodes(String errorCode, String objectName, String field, Class<?> fieldType) {
Set<String> codeList = new LinkedHashSet<>();
List<String> fieldList = new ArrayList<>();
buildFieldList(field, fieldList);
addCodes(codeList, errorCode, objectName, fieldList);
int dotIndex = field.lastIndexOf('.');
if (dotIndex != -1) {
buildFieldList(field.substring(dotIndex + 1), fieldList);
}
addCodes(codeList, errorCode, null, fieldList);
if (fieldType != null) {
addCode(codeList, errorCode, null, fieldType.getName());
}
addCode(codeList, errorCode, null, null);
return StringUtils.toStringArray(codeList);
}
private void addCodes(Collection<String> codeList, String errorCode, String objectName, Iterable<String> fields) {
for (String field : fields) {
addCode(codeList, errorCode, objectName, field);
}
}
private void addCode(Collection<String> codeList, String errorCode, String objectName, String field) {
codeList.add(postProcessMessageCode(this.formatter.format(errorCode, objectName, field)));
}
/**
* Add both keyed and non-keyed entries for the supplied {@code field}
* to the supplied field list.
*/
protected void buildFieldList(String field, List<String> fieldList) {
fieldList.add(field);
String plainField = field;
int keyIndex = plainField.lastIndexOf('[');
while (keyIndex != -1) {
int endKeyIndex = plainField.indexOf(']', keyIndex);
if (endKeyIndex != -1) {
plainField = plainField.substring(0, keyIndex) + plainField.substring(endKeyIndex + 1);
fieldList.add(plainField);
keyIndex = plainField.lastIndexOf('[');
}
else {
keyIndex = -1;
}
}
}
/**
* Post-process the given message code, built by this resolver.
* <p>The default implementation applies the specified prefix, if any.
* @param code the message code as built by this resolver
* @return the final message code to be returned
* @see #setPrefix
*/
protected String postProcessMessageCode(String code) {
return getPrefix() + code;
}
/**
* Common message code formats.
*
* @author Phillip Webb
* @author Chris Beams
* @since 3.2
* @see MessageCodeFormatter
* @see DefaultMessageCodesResolver#setMessageCodeFormatter(MessageCodeFormatter)
*/
public static enum Format implements MessageCodeFormatter {
/**
* Prefix the error code at the beginning of the generated message code. e.g.:
* {@code errorCode + "." + object name + "." + field}
*/
PREFIX_ERROR_CODE {
@Override
public String format(String errorCode, String objectName, String field) {
return toDelimitedString(errorCode, objectName, field);
}
},
/**
* Postfix the error code at the end of the generated message code. e.g.:
* {@code object name + "." + field + "." + errorCode}
*/
POSTFIX_ERROR_CODE {
@Override
public String format(String errorCode, String objectName, String field) {
return toDelimitedString(objectName, field, errorCode);
}
};
/**
* Concatenate the given elements, delimiting each with
* {@link DefaultMessageCodesResolver#CODE_SEPARATOR}, skipping zero-length or
* null elements altogether.
*/
public static String toDelimitedString(String... elements) {
StringBuilder rtn = new StringBuilder();
for (String element : elements) {
if (StringUtils.hasLength(element)) {
rtn.append(rtn.length() == 0 ? "" : CODE_SEPARATOR);
rtn.append(element);
}
}
return rtn.toString();
}
}
}