001/* 002 Licensed to the Apache Software Foundation (ASF) under one 003 or more contributor license agreements. See the NOTICE file 004 distributed with this work for additional information 005 regarding copyright ownership. The ASF licenses this file 006 to you under the Apache License, Version 2.0 (the 007 "License"); you may not use this file except in compliance 008 with the License. You may obtain a copy of the License at 009 010 http://www.apache.org/licenses/LICENSE-2.0 011 012 Unless required by applicable law or agreed to in writing, 013 software distributed under the License is distributed on an 014 "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 KIND, either express or implied. See the License for the 016 specific language governing permissions and limitations 017 under the License. 018 */ 019package org.apache.wiki.tags; 020 021import org.apache.wiki.api.core.Engine; 022import org.apache.wiki.api.exceptions.NoSuchVariableException; 023import org.apache.wiki.util.TextUtil; 024import org.apache.wiki.variables.VariableManager; 025 026import javax.servlet.jsp.JspException; 027import javax.servlet.jsp.JspWriter; 028import java.io.IOException; 029 030/** 031 * Returns the value of an Wiki variable. 032 * 033 * <P><B>Attributes</B></P> 034 * <UL> 035 * <LI>var - Name of the variable. Required. 036 * <LI>default - Revert to this value, if the value of "var" is null. 037 * If left out, this tag will produce a concise error message 038 * if the named variable is not found. Set to empty (default="") 039 * to hide the message. 040 * </UL> 041 * 042 * <P>A default value implies <I>failmode='quiet'</I>. 043 * 044 * @since 2.0 045 */ 046public class VariableTag extends WikiTagBase { 047 048 private static final long serialVersionUID = 0L; 049 050 private String m_var; 051 private String m_default; 052 053 @Override public void initTag() { 054 super.initTag(); 055 m_var = m_default = null; 056 } 057 058 public String getVar() 059 { 060 return m_var; 061 } 062 063 public void setVar( final String arg ) 064 { 065 m_var = arg; 066 } 067 068 public void setDefault( final String arg ) 069 { 070 m_default = arg; 071 } 072 073 @Override 074 public final int doWikiStartTag() throws JspException, IOException { 075 final Engine engine = m_wikiContext.getEngine(); 076 final JspWriter out = pageContext.getOut(); 077 String msg = null; 078 String value = null; 079 080 try { 081 value = engine.getManager( VariableManager.class ).getValue( m_wikiContext, getVar() ); 082 } catch( final NoSuchVariableException e ) { 083 msg = "No such variable: " + e.getMessage(); 084 } catch( final IllegalArgumentException e ) { 085 msg = "Incorrect variable name: " + e.getMessage(); 086 } 087 088 if( value == null ) { 089 value = m_default; 090 } 091 092 if( value == null ) { 093 value = msg; 094 } 095 out.write( TextUtil.replaceEntities(value) ); 096 return SKIP_BODY; 097 } 098 099}