Spring Framework example source code file (DefaultMessageCodesResolver.java)

This example Spring Framework source code file (DefaultMessageCodesResolver.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

arraylist, arraylist, class, code_separator, code_separator, defaultmessagecodesresolver, io, iterator, list, list, messagecodesresolver, serializable, string, string, util

The Spring Framework DefaultMessageCodesResolver.java source code

/*
 * Copyright 2002-2007 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.Iterator;
import java.util.List;

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:
 * <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>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
 * @since 1.0.1
 */
public class DefaultMessageCodesResolver implements MessageCodesResolver, Serializable {

	/**
	 * The separator that this implementation uses when resolving message codes.
	 */
	public static final String CODE_SEPARATOR = ".";


	private String prefix = "";


	/**
	 * 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 : "");
	}

	/**
	 * 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;
	}


	public String[] resolveMessageCodes(String errorCode, String objectName) {
		return new String[] {
				postProcessMessageCode(errorCode + CODE_SEPARATOR + objectName),
				postProcessMessageCode(errorCode)};
	}

	/**
	 * 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
	 */
	public String[] resolveMessageCodes(String errorCode, String objectName, String field, Class fieldType) {
		List codeList = new ArrayList();
		List fieldList = new ArrayList();
		buildFieldList(field, fieldList);
		for (Iterator it = fieldList.iterator(); it.hasNext();) {
			String fieldInList = (String) it.next();
			codeList.add(postProcessMessageCode(errorCode + CODE_SEPARATOR + objectName + CODE_SEPARATOR + fieldInList));
		}
		int dotIndex = field.lastIndexOf('.');
		if (dotIndex != -1) {
			buildFieldList(field.substring(dotIndex + 1), fieldList);
		}
		for (Iterator it = fieldList.iterator(); it.hasNext();) {
			String fieldInList = (String) it.next();
			codeList.add(postProcessMessageCode(errorCode + CODE_SEPARATOR + fieldInList));
		}
		if (fieldType != null) {
			codeList.add(postProcessMessageCode(errorCode + CODE_SEPARATOR + fieldType.getName()));
		}
		codeList.add(postProcessMessageCode(errorCode));
		return StringUtils.toStringArray(codeList);
	}

	/**
	 * Add both keyed and non-keyed entries for the supplied <code>field
	 * to the supplied field list.
	 */
	protected void buildFieldList(String field, List 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;
	}

}