org.apache.taglibs.standard.tag.common.fmt.TimeZoneSupport Maven / Gradle / Ivy
/*
* Copyright (c) 1997-2018 Oracle and/or its affiliates. All rights reserved.
* Copyright 2004 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.taglibs.standard.tag.common.fmt;
import java.io.IOException;
import java.util.TimeZone;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.jstl.core.Config;
import javax.servlet.jsp.tagext.BodyTagSupport;
import javax.servlet.jsp.tagext.Tag;
/**
* Support for tag handlers for <timeZone>, the time zone tag in
* JSTL 1.0.
*
* @author Jan Luehe
*/
public abstract class TimeZoneSupport extends BodyTagSupport {
//*********************************************************************
// Protected state
protected Object value; // 'value' attribute
//*********************************************************************
// Private state
private TimeZone timeZone;
//*********************************************************************
// Constructor and initialization
public TimeZoneSupport() {
super();
init();
}
private void init() {
value = null;
}
//*********************************************************************
// Collaboration with subtags
public TimeZone getTimeZone() {
return timeZone;
}
//*********************************************************************
// Tag logic
public int doStartTag() throws JspException {
if (value == null) {
timeZone = TimeZone.getTimeZone("GMT");
} else if (value instanceof String) {
if (((String) value).trim().equals("")) {
timeZone = TimeZone.getTimeZone("GMT");
} else {
timeZone = TimeZone.getTimeZone((String) value);
}
} else {
timeZone = (TimeZone) value;
}
return EVAL_BODY_BUFFERED;
}
public int doEndTag() throws JspException {
try {
pageContext.getOut().print(bodyContent.getString());
} catch (IOException ioe) {
throw new JspTagException(ioe.toString(), ioe);
}
return EVAL_PAGE;
}
// Releases any resources we may have (or inherit)
public void release() {
init();
}
//*********************************************************************
// Package-scoped utility methods
/*
* Determines and returns the time zone to be used by the given action.
*
* If the given action is nested inside a <timeZone> action,
* the time zone is taken from the enclosing <timeZone> action.
*
*
Otherwise, the time zone configuration setting
* javax.servlet.jsp.jstl.core.Config.FMT_TIME_ZONE
* is used.
*
* @param pageContext the page containing the action for which the
* time zone needs to be determined
* @param fromTag the action for which the time zone needs to be
* determined
*
* @return the time zone, or null if the given action is not
* nested inside a <timeZone> action and no time zone configuration
* setting exists
*/
static TimeZone getTimeZone(PageContext pc, Tag fromTag) {
TimeZone tz = null;
Tag t = findAncestorWithClass(fromTag, TimeZoneSupport.class);
if (t != null) {
// use time zone from parent tag
TimeZoneSupport parent = (TimeZoneSupport) t;
tz = parent.getTimeZone();
} else {
// get time zone from configuration setting
Object obj = Config.find(pc, Config.FMT_TIME_ZONE);
if (obj != null) {
if (obj instanceof TimeZone) {
tz = (TimeZone) obj;
} else {
tz = TimeZone.getTimeZone((String) obj);
}
}
}
return tz;
}
}