/*
* $Header: /home/cvspublic/jakarta-tomcat/src/share/org/apache/jasper/compiler/TagPoolGenerator.java,v 1.3 2001/05/11 18:42:54 clucas Exp $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
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*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.jasper.compiler;
import java.util.Hashtable;
import java.util.Enumeration;
import java.util.Vector;
import javax.servlet.jsp.tagext.TagLibraryInfo;
import javax.servlet.jsp.tagext.TagInfo;
import org.apache.jasper.Constants;
/**
* This class generates tag pooling related information. Specifically,
* it generates code to declare tag pools and to obtain tag pools
* during jsp initialization.
*
* @author Casey Lucas <clucas@armassolutions.com>
* @see org.apache.jasper.runtime.TagPoolManager
*/
public class TagPoolGenerator extends GeneratorBase
implements ClassDeclarationPhase, InitMethodPhase {
// Tag related info.
// Some of them aren't used now, but might be in the future.
private String prefix;
private String shortTagName;
private TagLibraryInfo tli;
private TagInfo ti;
private Hashtable attrs;
// Computed pool name and pool name as a valid variable name
private String poolName;
private String poolVarName;
private final static String POOL_VARIABLE_NAME_PREFIX = "_jspx_tagPool_";
/**
* No default constructor.
*/
private TagPoolGenerator() {
}
/**
* Common constructor with enough information to generate code.
*
* @param prefix
* @param shortTagName
* @param attrs
* @param tli
* @param ti
*/
public TagPoolGenerator(String prefix, String shortTagName,
Hashtable attrs, TagLibraryInfo tli,
TagInfo ti) {
this.prefix = prefix;
this.shortTagName = shortTagName;
this.tli = tli;
this.ti = ti;
this.attrs = attrs;
this.poolName = getPoolName(tli, ti, attrs);
this.poolVarName = getPoolVariableName(poolName);
}
/**
* This method returns a unique pool name based on the given
* TagLibraryInfo, TagInfo, and set of tag attributes. Tag
* attribute order does not affect the returned name.
*
* @param tli
* @param ti
* @param attributes
* @return unique pool name based on parameters
*/
public static String getPoolName(TagLibraryInfo tli, TagInfo ti, Hashtable attributes) {
return getSafeVariableName(tli.getURI() + "_" + ti.getTagName() + getStringFromAttributes(attributes));
}
/**
* This method returns a unique pool variable name given
* TagLibraryInfo, TagInfo and set of tag attributes.
*
* @param tli
* @param ti
* @param attributes
* @return unique pool variable name based on parameters
*/
public static String getPoolVariableName(TagLibraryInfo tli, TagInfo ti, Hashtable attributes) {
return getPoolVariableName(getPoolName(tli, ti, attributes));
}
/**
* This method returns a unique pool variable name given
* a unique pool name
*
* @param poolName
* @return unique pool variable name
*/
public static String getPoolVariableName(String poolName) {
return getSafeVariableName(POOL_VARIABLE_NAME_PREFIX + poolName);
}
/**
* This method generates code from based on the jsp. During
* class declaration phase, it declares a tag pool for this
* tag. During the initilization phase, it generates code
* to lookup a pool from the tag pool manager.
*
* @param writer
* @param phase
*/
public void generate(ServletWriter writer, Class phase) {
if (ClassDeclarationPhase.class.isAssignableFrom(phase)) {
writer.println(Constants.JSP_RUNTIME_PACKAGE +
".TagHandlerPool " + poolVarName + " = null;");
} else if (InitMethodPhase.class.isAssignableFrom(phase)) {
writer.println("if (" + TagPoolManagerGenerator.MANAGER_VARIABLE + " != null) {");
writer.pushIndent();
writer.println(poolVarName + " = ");
writer.pushIndent();
writer.println(TagPoolManagerGenerator.MANAGER_VARIABLE + ".getPool(\"" + poolName + "\",");
writer.println(ti.getTagClassName() + ".class);");
writer.popIndent();
writer.popIndent();
writer.println("}");
}
}
/**
* This method generates a string based on a set of tag attributes.
* It sorts the attributes by name then concatenates them.
*
* @param attributes
* @return string based on tag attributes
*/
private static String getStringFromAttributes(Hashtable attributes) {
if (attributes == null || attributes.isEmpty()) {
return "";
} else {
Vector sortedAttributes = new Vector(attributes.size());
Enumeration elements = attributes.keys();
int i;
while (elements.hasMoreElements()) {
String attributeName = (String) elements.nextElement();
for (i=0; i<sortedAttributes.size(); i++) {
if (attributeName.compareTo((String) sortedAttributes.elementAt(i)) < 0) {
break;
}
}
sortedAttributes.insertElementAt(attributeName, i);
}
// cat the attributes
StringBuffer buffer = new StringBuffer();
for (i=0; i<sortedAttributes.size(); i++) {
buffer.append('_');
buffer.append(sortedAttributes.elementAt(i));
}
return buffer.toString();
}
}
/**
* Constant that holds the characters that can be valid first
* characters of a java variable.
*/
private static final String VALID_FIRST_CHARS =
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_";
/**
* Constant that holds the characters that can be used as in
* a valid java variable name -- non first char case.
*/
private static final String VALID_CHARS = VALID_FIRST_CHARS + "1234567890";
/**
* This method generates a string that can be used as a java
* variable name. Characters that cant be used are replaced
* with an underscore.
*
* @param s
* @return string that can be used as java variable name
*/
private static String getSafeVariableName(String s) {
StringBuffer buffer = new StringBuffer();
String compareAgainst = VALID_FIRST_CHARS;
for (int i=0; i<s.length(); i++) {
if (i == 1) {
compareAgainst = VALID_CHARS;
}
if (compareAgainst.indexOf(s.charAt(i)) != -1) {
buffer.append(s.charAt(i));
} else {
buffer.append('_');
}
}
return buffer.toString();
}
}