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/*
* $Id: MessageResources.java 264684 2005-08-30 03:08:01Z niallp $
*
* Copyright 1999-2005 The Apache Software Foundation.
*
* 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.apache.struts.util;
import java.io.Serializable;
import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Locale;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* General purpose abstract class that describes an API for retrieving
* Locale-sensitive messages from underlying resource locations of an
* unspecified design, and optionally utilizing the MessageFormat
* class to produce internationalized messages with parametric replacement.
*
* Calls to getMessage() variants without a Locale
* argument are presumed to be requesting a message string in the default
* Locale for this JVM.
*
* Calls to getMessage() with an unknown key, or an unknown
* Locale will return null if the
* returnNull property is set to true. Otherwise,
* a suitable error message will be returned instead.
*
* IMPLEMENTATION NOTE - Classes that extend this class
* must be Serializable so that instances may be used in distributable
* application server environments.
*
* @version $Rev: 264684 $ $Date: 2005-08-30 04:08:01 +0100 (Tue, 30 Aug 2005) $
*/
public abstract class MessageResources implements Serializable {
// ------------------------------------------------------------- Properties
/**
* Commons Logging instance.
*/
protected static Log log = LogFactory.getLog(MessageResources.class);
/**
* The configuration parameter used to initialize this MessageResources.
*/
protected String config = null;
/**
* The configuration parameter used to initialize this MessageResources.
* @return parameter used to initialize this MessageResources
*/
public String getConfig() {
return (this.config);
}
/**
* The default Locale for our environment.
*/
protected Locale defaultLocale = Locale.getDefault();
/**
* The MessageResourcesFactory that created this instance.
*/
protected MessageResourcesFactory factory = null;
/**
* The MessageResourcesFactory that created this instance.
* @return MessageResourcesFactory that created instance
*/
public MessageResourcesFactory getFactory() {
return (this.factory);
}
/**
* The set of previously created MessageFormat objects, keyed by the
* key computed in messageKey().
*/
protected HashMap formats = new HashMap();
/**
* Indicate is a null is returned instead of an error message string
* when an unknown Locale or key is requested.
*/
protected boolean returnNull = false;
/**
* Indicates that a null is returned instead of an error message string
* if an unknown Locale or key is requested.
* @return true if null is returned if unknown key or locale is requested
*/
public boolean getReturnNull() {
return (this.returnNull);
}
/**
* Indicates that a null is returned instead of an error message string
* if an unknown Locale or key is requested.
* @param returnNull true Indicates that a null is returned
* if an unknown Locale or key is requested.
*/
public void setReturnNull(boolean returnNull) {
this.returnNull = returnNull;
}
/**
* Indicates whether 'escape processing' should be performed on
* the error message string.
*/
private boolean escape = true;
/**
* Indicates whether 'escape processing' should be performed on
* the error message string.
*
* @since Struts 1.2.8
*/
public boolean isEscape() {
return escape;
}
/**
* Set whether 'escape processing' should be performed on
* the error message string.
*
* @since Struts 1.2.8
*/
public void setEscape(boolean escape) {
this.escape = escape;
}
// ----------------------------------------------------------- Constructors
/**
* Construct a new MessageResources according to the specified parameters.
*
* @param factory The MessageResourcesFactory that created us
* @param config The configuration parameter for this MessageResources
*/
public MessageResources(MessageResourcesFactory factory, String config) {
this(factory, config, false);
}
/**
* Construct a new MessageResources according to the specified parameters.
*
* @param factory The MessageResourcesFactory that created us
* @param config The configuration parameter for this MessageResources
* @param returnNull The returnNull property we should initialize with
*/
public MessageResources(
MessageResourcesFactory factory,
String config,
boolean returnNull) {
super();
this.factory = factory;
this.config = config;
this.returnNull = returnNull;
}
// --------------------------------------------------------- Public Methods
/**
* Returns a text message for the specified key, for the default Locale.
*
* @param key The message key to look up
*/
public String getMessage(String key) {
return this.getMessage((Locale) null, key, null);
}
/**
* Returns a text message after parametric replacement of the specified
* parameter placeholders.
*
* @param key The message key to look up
* @param args An array of replacement parameters for placeholders
*/
public String getMessage(String key, Object args[]) {
return this.getMessage((Locale) null, key, args);
}
/**
* Returns a text message after parametric replacement of the specified
* parameter placeholders.
*
* @param key The message key to look up
* @param arg0 The replacement for placeholder {0} in the message
*/
public String getMessage(String key, Object arg0) {
return this.getMessage((Locale) null, key, arg0);
}
/**
* Returns a text message after parametric replacement of the specified
* parameter placeholders.
*
* @param key The message key to look up
* @param arg0 The replacement for placeholder {0} in the message
* @param arg1 The replacement for placeholder {1} in the message
*/
public String getMessage(String key, Object arg0, Object arg1) {
return this.getMessage((Locale) null, key, arg0, arg1);
}
/**
* Returns a text message after parametric replacement of the specified
* parameter placeholders.
*
* @param key The message key to look up
* @param arg0 The replacement for placeholder {0} in the message
* @param arg1 The replacement for placeholder {1} in the message
* @param arg2 The replacement for placeholder {2} in the message
*/
public String getMessage(String key, Object arg0, Object arg1, Object arg2) {
return this.getMessage((Locale) null, key, arg0, arg1, arg2);
}
/**
* Returns a text message after parametric replacement of the specified
* parameter placeholders.
*
* @param key The message key to look up
* @param arg0 The replacement for placeholder {0} in the message
* @param arg1 The replacement for placeholder {1} in the message
* @param arg2 The replacement for placeholder {2} in the message
* @param arg3 The replacement for placeholder {3} in the message
*/
public String getMessage(
String key,
Object arg0,
Object arg1,
Object arg2,
Object arg3) {
return this.getMessage((Locale) null, key, arg0, arg1, arg2, arg3);
}
/**
* Returns a text message for the specified key, for the default Locale.
* A null string result will be returned by this method if no relevant
* message resource is found for this key or Locale, if the
* returnNull property is set. Otherwise, an appropriate
* error message will be returned.
*
* This method must be implemented by a concrete subclass.
*
* @param locale The requested message Locale, or null
* for the system default Locale
* @param key The message key to look up
*/
public abstract String getMessage(Locale locale, String key);
/**
* Returns a text message after parametric replacement of the specified
* parameter placeholders. A null string result will be returned by
* this method if no resource bundle has been configured.
*
* @param locale The requested message Locale, or null
* for the system default Locale
* @param key The message key to look up
* @param args An array of replacement parameters for placeholders
*/
public String getMessage(Locale locale, String key, Object args[]) {
// Cache MessageFormat instances as they are accessed
if (locale == null) {
locale = defaultLocale;
}
MessageFormat format = null;
String formatKey = messageKey(locale, key);
synchronized (formats) {
format = (MessageFormat) formats.get(formatKey);
if (format == null) {
String formatString = getMessage(locale, key);
if (formatString == null) {
return returnNull ? null : ("???" + formatKey + "???");
}
format = new MessageFormat(escape(formatString));
format.setLocale(locale);
formats.put(formatKey, format);
}
}
return format.format(args);
}
/**
* Returns a text message after parametric replacement of the specified
* parameter placeholders. A null string result will never be returned
* by this method.
*
* @param locale The requested message Locale, or null
* for the system default Locale
* @param key The message key to look up
* @param arg0 The replacement for placeholder {0} in the message
*/
public String getMessage(Locale locale, String key, Object arg0) {
return this.getMessage(locale, key, new Object[] { arg0 });
}
/**
* Returns a text message after parametric replacement of the specified
* parameter placeholders. A null string result will never be returned
* by this method.
*
* @param locale The requested message Locale, or null
* for the system default Locale
* @param key The message key to look up
* @param arg0 The replacement for placeholder {0} in the message
* @param arg1 The replacement for placeholder {1} in the message
*/
public String getMessage(Locale locale, String key, Object arg0, Object arg1) {
return this.getMessage(locale, key, new Object[] { arg0, arg1 });
}
/**
* Returns a text message after parametric replacement of the specified
* parameter placeholders. A null string result will never be returned
* by this method.
*
* @param locale The requested message Locale, or null
* for the system default Locale
* @param key The message key to look up
* @param arg0 The replacement for placeholder {0} in the message
* @param arg1 The replacement for placeholder {1} in the message
* @param arg2 The replacement for placeholder {2} in the message
*/
public String getMessage(
Locale locale,
String key,
Object arg0,
Object arg1,
Object arg2) {
return this.getMessage(locale, key, new Object[] { arg0, arg1, arg2 });
}
/**
* Returns a text message after parametric replacement of the specified
* parameter placeholders. A null string result will never be returned
* by this method.
*
* @param locale The requested message Locale, or null
* for the system default Locale
* @param key The message key to look up
* @param arg0 The replacement for placeholder {0} in the message
* @param arg1 The replacement for placeholder {1} in the message
* @param arg2 The replacement for placeholder {2} in the message
* @param arg3 The replacement for placeholder {3} in the message
*/
public String getMessage(
Locale locale,
String key,
Object arg0,
Object arg1,
Object arg2,
Object arg3) {
return this.getMessage(locale, key, new Object[] { arg0, arg1, arg2, arg3 });
}
/**
* Return true if there is a defined message for the specified
* key in the system default locale.
*
* @param key The message key to look up
*/
public boolean isPresent(String key) {
return this.isPresent(null, key);
}
/**
* Return true if there is a defined message for the specified
* key in the specified Locale.
*
* @param locale The requested message Locale, or null
* for the system default Locale
* @param key The message key to look up
*/
public boolean isPresent(Locale locale, String key) {
String message = getMessage(locale, key);
if (message == null) {
return false;
} else if (message.startsWith("???") && message.endsWith("???")) {
return false; // FIXME - Only valid for default implementation
} else {
return true;
}
}
// ------------------------------------------------------ Protected Methods
/**
* Escape any single quote characters that are included in the specified
* message string.
*
* @param string The string to be escaped
*/
protected String escape(String string) {
if (!isEscape()) {
return string;
}
if ((string == null) || (string.indexOf('\'') < 0)) {
return string;
}
int n = string.length();
StringBuffer sb = new StringBuffer(n);
for (int i = 0; i < n; i++) {
char ch = string.charAt(i);
if (ch == '\'') {
sb.append('\'');
}
sb.append(ch);
}
return sb.toString();
}
/**
* Compute and return a key to be used in caching information by a Locale.
* NOTE - The locale key for the default Locale in our
* environment is a zero length String.
*
* @param locale The locale for which a key is desired
*/
protected String localeKey(Locale locale) {
return (locale == null) ? "" : locale.toString();
}
/**
* Compute and return a key to be used in caching information
* by Locale and message key.
*
* @param locale The Locale for which this format key is calculated
* @param key The message key for which this format key is calculated
*/
protected String messageKey(Locale locale, String key) {
return (localeKey(locale) + "." + key);
}
/**
* Compute and return a key to be used in caching information
* by locale key and message key.
*
* @param localeKey The locale key for which this cache key is calculated
* @param key The message key for which this cache key is calculated
*/
protected String messageKey(String localeKey, String key) {
return (localeKey + "." + key);
}
// --------------------------------------------------------- Static Methods
/**
* The default MessageResourcesFactory used to create MessageResources
* instances.
*/
protected static MessageResourcesFactory defaultFactory = null;
/**
* Create and return an instance of MessageResources for the
* created by the default MessageResourcesFactory.
*
* @param config Configuration parameter for this message bundle.
*/
public synchronized static MessageResources getMessageResources(String config) {
if (defaultFactory == null) {
defaultFactory = MessageResourcesFactory.createFactory();
}
return defaultFactory.createResources(config);
}
/**
* Log a message to the Writer that has been configured for our use.
*
* @param message The message to be logged
*/
public void log(String message) {
log.debug(message);
}
/**
* Log a message and exception to the Writer that has been configured
* for our use.
*
* @param message The message to be logged
* @param throwable The exception to be logged
*/
public void log(String message, Throwable throwable) {
log.debug(message, throwable);
}
}