/*
* 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.web.servlet.tags;
import java.io.IOException;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspTagException;
import org.springframework.context.MessageSource;
import org.springframework.context.MessageSourceResolvable;
import org.springframework.context.NoSuchMessageException;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.util.JavaScriptUtils;
import org.springframework.web.util.TagUtils;
/**
* Custom JSP tag to look up a message in the scope of this page. Messages are
* resolved using the ApplicationContext and thus support internationalization.
*
* <p>Detects an HTML escaping setting, either on this tag instance, the page level,
* or the {@code web.xml} level. Can also apply JavaScript escaping.
*
* <p>If "code" isn't set or cannot be resolved, "text" will be used as default
* message. Thus, this tag can also be used for HTML escaping of any texts.
*
* <p>Message arguments can be specified via the {@link #setArguments(Object) arguments}
* attribute or by using nested {@code <spring:argument>} tags.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @author Nicholas Williams
* @see #setCode
* @see #setText
* @see #setHtmlEscape
* @see #setJavaScriptEscape
* @see HtmlEscapeTag#setDefaultHtmlEscape
* @see org.springframework.web.util.WebUtils#HTML_ESCAPE_CONTEXT_PARAM
* @see ArgumentTag
*/
@SuppressWarnings("serial")
public class MessageTag extends HtmlEscapingAwareTag implements ArgumentAware {
/**
* Default separator for splitting an arguments String: a comma (",")
*/
public static final String DEFAULT_ARGUMENT_SEPARATOR = ",";
private MessageSourceResolvable message;
private String code;
private Object arguments;
private String argumentSeparator = DEFAULT_ARGUMENT_SEPARATOR;
private List<Object> nestedArguments;
private String text;
private String var;
private String scope = TagUtils.SCOPE_PAGE;
private boolean javaScriptEscape = false;
/**
* Set the MessageSourceResolvable for this tag.
* <p>If a MessageSourceResolvable is specified, it effectively overrides
* any code, arguments or text specified on this tag.
*/
public void setMessage(MessageSourceResolvable message) {
this.message = message;
}
/**
* Set the message code for this tag.
*/
public void setCode(String code) {
this.code = code;
}
/**
* Set optional message arguments for this tag, as a comma-delimited
* String (each String argument can contain JSP EL), an Object array
* (used as argument array), or a single Object (used as single argument).
*/
public void setArguments(Object arguments) {
this.arguments = arguments;
}
/**
* Set the separator to use for splitting an arguments String.
* Default is a comma (",").
* @see #setArguments
*/
public void setArgumentSeparator(String argumentSeparator) {
this.argumentSeparator = argumentSeparator;
}
@Override
public void addArgument(Object argument) throws JspTagException {
this.nestedArguments.add(argument);
}
/**
* Set the message text for this tag.
*/
public void setText(String text) {
this.text = text;
}
/**
* Set PageContext attribute name under which to expose
* a variable that contains the resolved message.
* @see #setScope
* @see javax.servlet.jsp.PageContext#setAttribute
*/
public void setVar(String var) {
this.var = var;
}
/**
* Set the scope to export the variable to.
* Default is SCOPE_PAGE ("page").
* @see #setVar
* @see org.springframework.web.util.TagUtils#SCOPE_PAGE
* @see javax.servlet.jsp.PageContext#setAttribute
*/
public void setScope(String scope) {
this.scope = scope;
}
/**
* Set JavaScript escaping for this tag, as boolean value.
* Default is "false".
*/
public void setJavaScriptEscape(boolean javaScriptEscape) throws JspException {
this.javaScriptEscape = javaScriptEscape;
}
@Override
protected final int doStartTagInternal() throws JspException, IOException {
this.nestedArguments = new LinkedList<>();
return EVAL_BODY_INCLUDE;
}
/**
* Resolves the message, escapes it if demanded,
* and writes it to the page (or exposes it as variable).
* @see #resolveMessage()
* @see org.springframework.web.util.HtmlUtils#htmlEscape(String)
* @see org.springframework.web.util.JavaScriptUtils#javaScriptEscape(String)
* @see #writeMessage(String)
*/
@Override
public int doEndTag() throws JspException {
try {
// Resolve the unescaped message.
String msg = resolveMessage();
// HTML and/or JavaScript escape, if demanded.
msg = htmlEscape(msg);
msg = this.javaScriptEscape ? JavaScriptUtils.javaScriptEscape(msg) : msg;
// Expose as variable, if demanded, else write to the page.
if (this.var != null) {
pageContext.setAttribute(this.var, msg, TagUtils.getScope(this.scope));
}
else {
writeMessage(msg);
}
return EVAL_PAGE;
}
catch (IOException ex) {
throw new JspTagException(ex.getMessage(), ex);
}
catch (NoSuchMessageException ex) {
throw new JspTagException(getNoSuchMessageExceptionDescription(ex));
}
}
@Override
public void release() {
super.release();
this.arguments = null;
}
/**
* Resolve the specified message into a concrete message String.
* The returned message String should be unescaped.
*/
protected String resolveMessage() throws JspException, NoSuchMessageException {
MessageSource messageSource = getMessageSource();
if (messageSource == null) {
throw new JspTagException("No corresponding MessageSource found");
}
// Evaluate the specified MessageSourceResolvable, if any.
if (this.message != null) {
// We have a given MessageSourceResolvable.
return messageSource.getMessage(this.message, getRequestContext().getLocale());
}
if (this.code != null || this.text != null) {
// We have a code or default text that we need to resolve.
Object[] argumentsArray = resolveArguments(this.arguments);
if (!this.nestedArguments.isEmpty()) {
argumentsArray = appendArguments(argumentsArray,
this.nestedArguments.toArray());
}
if (this.text != null) {
// We have a fallback text to consider.
return messageSource.getMessage(
this.code, argumentsArray, this.text, getRequestContext().getLocale());
}
else {
// We have no fallback text to consider.
return messageSource.getMessage(
this.code, argumentsArray, getRequestContext().getLocale());
}
}
// All we have is a specified literal text.
return this.text;
}
private Object[] appendArguments(Object[] sourceArguments, Object[] additionalArguments) {
if (ObjectUtils.isEmpty(sourceArguments)) {
return additionalArguments;
}
Object[] arguments = new Object[sourceArguments.length + additionalArguments.length];
System.arraycopy(sourceArguments, 0, arguments, 0, sourceArguments.length);
System.arraycopy(additionalArguments, 0, arguments, sourceArguments.length, additionalArguments.length);
return arguments;
}
/**
* Resolve the given arguments Object into an arguments array.
* @param arguments the specified arguments Object
* @return the resolved arguments as array
* @throws JspException if argument conversion failed
* @see #setArguments
*/
protected Object[] resolveArguments(Object arguments) throws JspException {
if (arguments instanceof String) {
String[] stringArray =
StringUtils.delimitedListToStringArray((String) arguments, this.argumentSeparator);
if (stringArray.length == 1) {
Object argument = stringArray[0];
if (argument != null && argument.getClass().isArray()) {
return ObjectUtils.toObjectArray(argument);
}
else {
return new Object[] {argument};
}
}
else {
return stringArray;
}
}
else if (arguments instanceof Object[]) {
return (Object[]) arguments;
}
else if (arguments instanceof Collection) {
return ((Collection<?>) arguments).toArray();
}
else if (arguments != null) {
// Assume a single argument object.
return new Object[] {arguments};
}
else {
return null;
}
}
/**
* Write the message to the page.
* <p>Can be overridden in subclasses, e.g. for testing purposes.
* @param msg the message to write
* @throws IOException if writing failed
*/
protected void writeMessage(String msg) throws IOException {
pageContext.getOut().write(String.valueOf(msg));
}
/**
* Use the current RequestContext's application context as MessageSource.
*/
protected MessageSource getMessageSource() {
return getRequestContext().getMessageSource();
}
/**
* Return default exception message.
*/
protected String getNoSuchMessageExceptionDescription(NoSuchMessageException ex) {
return ex.getMessage();
}
}