Java tutorial
/* * $Id: Date.java 497654 2007-01-19 00:21:57Z rgielen $ * * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.struts2.components; import java.io.IOException; import java.io.Writer; import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.struts2.views.annotations.StrutsTag; import org.apache.struts2.views.annotations.StrutsTagAttribute; import com.opensymphony.xwork2.ActionContext; import com.opensymphony.xwork2.TextProvider; import com.opensymphony.xwork2.util.ValueStack; /** * <!-- START SNIPPET: javadoc --> * * Format Date object in different ways. * <p> * The date tag will allow you to format a Date in a quick and easy way. * You can specify a <b>custom format</b> (eg. "dd/MM/yyyy hh:mm"), you can generate * <b>easy readable notations</b> (like "in 2 hours, 14 minutes"), or you can just fall back * on a <b>predefined format</b> with key 'struts.date.format' in your properties file. * * If that key is not defined, it will finally fall back to the default DateFormat.MEDIUM * formatting. * * <b>Note</b>: If the requested Date object isn't found on the stack, a blank will be returned. * </p> * * Configurable attributes are :- * <ul> * <li>name</li> * <li>nice</li> * <li>format</li> * </ul> * * <p/> * * Following how the date component will work, depending on the value of nice attribute * (which by default is false) and the format attribute. * * <p/> * * <b><u>Condition 1: With nice attribute as true</u></b> * <table border="1"> * <tr> * <td>i18n key</td> * <td>default</td> * </tr> * <tr> * <td>struts.date.format.past</td> * <td>{0} ago</td> * </tr> * <tr> * <td>struts.date.format.future</td> * <td>in {0}</td> * </tr> * <tr> * <td>struts.date.format.seconds</td> * <td>an instant</td> * </tr> * <tr> * <td>struts.date.format.minutes</td> * <td>{0,choice,1#one minute|1<{0} minutes}</td> * </tr> * <tr> * <td>struts.date.format.hours</td> * <td>{0,choice,1#one hour|1<{0} hours}{1,choice,0#|1#, one minute|1<, {1} minutes}</td> * </tr> * <tr> * <td>struts.date.format.days</td> * <td>{0,choice,1#one day|1<{0} days}{1,choice,0#|1#, one hour|1<, {1} hours}</td> * </tr> * <tr> * <td>struts.date.format.years</td> * <td>{0,choice,1#one year|1<{0} years}{1,choice,0#|1#, one day|1<, {1} days}</td> * </tr> * </table> * * <p/> * * <b><u>Condition 2: With nice attribute as false and format attribute is specified eg. dd/MM/yyyyy </u></b> * <p>In this case the format attribute will be used.</p> * * <p/> * * <b><u>Condition 3: With nice attribute as false and no format attribute is specified </u></b> * <table border="1"> * <tr> * <td>i18n key</td> * <td>default</td> * </tr> * <tr> * <td>struts.date.format</td> * <td>if one is not found DateFormat.MEDIUM format will be used</td> * </tr> * </table> * * * <!-- END SNIPPET: javadoc --> * * <p/> <b>Examples</b> * <pre> * <!-- START SNIPPET: example --> * <s:date name="person.birthday" format="dd/MM/yyyy" /> * <s:date name="person.birthday" format="%{getText('some.i18n.key')}" /> * <s:date name="person.birthday" nice="true" /> * <s:date name="person.birthday" /> * <!-- END SNIPPET: example --> * </pre> * * <code>Date</code> * */ @StrutsTag(name = "date", tldBodyContent = "empty", tldTagClass = "org.apache.struts2.views.jsp.DateTag", description = "Render a formatted date.") public class Date extends Component { private static final Log LOG = LogFactory.getLog(Date.class); /** * Property name to fall back when no format is specified */ public static final String DATETAG_PROPERTY = "struts.date.format"; /** * Property name that defines the past notation (default: {0} ago) */ public static final String DATETAG_PROPERTY_PAST = "struts.date.format.past"; private static final String DATETAG_DEFAULT_PAST = "{0} ago"; /** * Property name that defines the future notation (default: in {0}) */ public static final String DATETAG_PROPERTY_FUTURE = "struts.date.format.future"; private static final String DATETAG_DEFAULT_FUTURE = "in {0}"; /** * Property name that defines the seconds notation (default: in instant) */ public static final String DATETAG_PROPERTY_SECONDS = "struts.date.format.seconds"; private static final String DATETAG_DEFAULT_SECONDS = "an instant"; /** * Property name that defines the minutes notation (default: {0,choice,1#one minute|1<{0} minutes}) */ public static final String DATETAG_PROPERTY_MINUTES = "struts.date.format.minutes"; private static final String DATETAG_DEFAULT_MINUTES = "{0,choice,1#one minute|1<{0} minutes}"; /** * Property name that defines the hours notation (default: {0,choice,1#one hour|1<{0} hours}{1,choice,0#|1#, one * minute|1<, {1} minutes}) */ public static final String DATETAG_PROPERTY_HOURS = "struts.date.format.hours"; private static final String DATETAG_DEFAULT_HOURS = "{0,choice,1#one hour|1<{0} hours}{1,choice,0#|1#, one minute|1<, {1} minutes}"; /** * Property name that defines the days notation (default: {0,choice,1#one day|1<{0} days}{1,choice,0#|1#, one hour|1<, * {1} hours}) */ public static final String DATETAG_PROPERTY_DAYS = "struts.date.format.days"; private static final String DATETAG_DEFAULT_DAYS = "{0,choice,1#one day|1<{0} days}{1,choice,0#|1#, one hour|1<, {1} hours}"; /** * Property name that defines the years notation (default: {0,choice,1#one year|1<{0} years}{1,choice,0#|1#, one * day|1<, {1} days}) */ public static final String DATETAG_PROPERTY_YEARS = "struts.date.format.years"; private static final String DATETAG_DEFAULT_YEARS = "{0,choice,1#one year|1<{0} years}{1,choice,0#|1#, one day|1<, {1} days}"; private String name; private String format; private boolean nice; public Date(ValueStack stack) { super(stack); } private TextProvider findProviderInStack() { for (Iterator iterator = getStack().getRoot().iterator(); iterator.hasNext();) { Object o = iterator.next(); if (o instanceof TextProvider) { return (TextProvider) o; } } return null; } /** * Calculates the difference in time from now to the given date, and outputs it nicely. <p/> An example: <br/>Now = * 2006/03/12 13:38:00, date = 2006/03/12 15:50:00 will output "in 1 hour, 12 minutes". * * @param tp text provider * @param date the date * @return the date nicely */ public String formatTime(TextProvider tp, java.util.Date date) { java.util.Date now = new java.util.Date(); StringBuffer sb = new StringBuffer(); List args = new ArrayList(); long secs = Math.abs((now.getTime() - date.getTime()) / 1000); long mins = secs / 60; long sec = secs % 60; int min = (int) mins % 60; long hours = mins / 60; int hour = (int) hours % 24; int days = (int) hours / 24; int day = days % 365; int years = days / 365; if (years > 0) { args.add(new Long(years)); args.add(new Long(day)); args.add(sb); args.add(null); sb.append(tp.getText(DATETAG_PROPERTY_YEARS, DATETAG_DEFAULT_YEARS, args)); } else if (day > 0) { args.add(new Long(day)); args.add(new Long(hour)); args.add(sb); args.add(null); sb.append(tp.getText(DATETAG_PROPERTY_DAYS, DATETAG_DEFAULT_DAYS, args)); } else if (hour > 0) { args.add(new Long(hour)); args.add(new Long(min)); args.add(sb); args.add(null); sb.append(tp.getText(DATETAG_PROPERTY_HOURS, DATETAG_DEFAULT_HOURS, args)); } else if (min > 0) { args.add(new Long(min)); args.add(new Long(sec)); args.add(sb); args.add(null); sb.append(tp.getText(DATETAG_PROPERTY_MINUTES, DATETAG_DEFAULT_MINUTES, args)); } else { args.add(new Long(sec)); args.add(sb); args.add(null); sb.append(tp.getText(DATETAG_PROPERTY_SECONDS, DATETAG_DEFAULT_SECONDS, args)); } args.clear(); args.add(sb.toString()); if (date.before(now)) { // looks like this date is passed return tp.getText(DATETAG_PROPERTY_PAST, DATETAG_DEFAULT_PAST, args); } else { return tp.getText(DATETAG_PROPERTY_FUTURE, DATETAG_DEFAULT_FUTURE, args); } } public boolean end(Writer writer, String body) { String msg = null; ValueStack stack = getStack(); java.util.Date date = null; // find the name on the valueStack, and cast it to a date try { date = (java.util.Date) findValue(name); } catch (Exception e) { LOG.error("Could not convert object with key '" + name + "' to a java.util.Date instance"); // bad date, return a blank instead ? msg = ""; } //try to find the format on the stack if (format != null) { format = findString(format); } if (date != null) { TextProvider tp = findProviderInStack(); if (tp != null) { if (nice) { msg = formatTime(tp, date); } else { if (format == null) { String globalFormat = null; // if the format is not specified, fall back using the // defined property DATETAG_PROPERTY globalFormat = tp.getText(DATETAG_PROPERTY); // if tp.getText can not find the property then the // returned string is the same as input = // DATETAG_PROPERTY if (globalFormat != null && !DATETAG_PROPERTY.equals(globalFormat)) { msg = new SimpleDateFormat(globalFormat, ActionContext.getContext().getLocale()) .format(date); } else { msg = DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.MEDIUM, ActionContext.getContext().getLocale()).format(date); } } else { msg = new SimpleDateFormat(format, ActionContext.getContext().getLocale()).format(date); } } if (msg != null) { try { if (getId() == null) { writer.write(msg); } else { stack.getContext().put(getId(), msg); } } catch (IOException e) { LOG.error("Could not write out Date tag", e); } } } } return super.end(writer, ""); } @StrutsTagAttribute(description = "Date or DateTime format pattern", rtexprvalue = false) public void setFormat(String format) { this.format = format; } @StrutsTagAttribute(description = "Whether to print out the date nicely", type = "Boolean", defaultValue = "false") public void setNice(boolean nice) { this.nice = nice; } /** * @return Returns the name. */ public String getName() { return name; } @StrutsTagAttribute(description = "The date value to format", required = true) public void setName(String name) { this.name = name; } /** * @return Returns the format. */ public String getFormat() { return format; } /** * @return Returns the nice. */ public boolean isNice() { return nice; } }