/*
* Copyright (c) 1998-2011 Caucho Technology -- all rights reserved
*
* This file is part of Resin(R) Open Source
*
* Each copy or derived work must preserve the copyright notice and this
* notice unmodified.
*
* Resin Open Source is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Resin Open Source is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
* of NON-INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with Resin Open Source; if not, write to the
* Free SoftwareFoundation, Inc.
* 59 Temple Place, Suite 330
* Boston, MA 02111-1307 USA
*
* @author Scott Ferguson
*/
package com.caucho.jsp.java;
import com.caucho.jsp.JspParseException;
import com.caucho.vfs.WriteStream;
import com.caucho.xml.QName;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.Modifier;
/**
* Represents a Java scriptlet.
*/
public class JspUseBean extends JspContainerNode {
private static final QName ID = new QName("id");
private static final QName TYPE = new QName("type");
private static final QName CLASS = new QName("class");
private static final QName BEAN_NAME = new QName("beanName");
private static final QName SCOPE = new QName("scope");
private String _id;
private String _typeName;
private String _className;
private String _beanName;
private String _scope;
/**
* Adds an attribute.
*/
public void addAttribute(QName name, String value)
throws JspParseException
{
if (ID.equals(name))
_id = value;
else if (TYPE.equals(name))
_typeName = value;
else if (CLASS.equals(name))
_className = value;
else if (BEAN_NAME.equals(name))
_beanName = value;
else if (SCOPE.equals(name))
_scope = value;
else
throw error(L.l("'{0}' is an invalid attribute in <jsp:useBean>",
name.getName()));
}
/**
* Adds text to the scriptlet.
*/
public JspNode addText(String text)
throws JspParseException
{
JspNode node = new StaticText(_gen, text, this);
addChild(node);
return node;
}
/**
* Generates the XML text representation for the tag validation.
*
* @param os write stream to the generated XML.
*/
public void printXml(WriteStream os)
throws IOException
{
os.print("<jsp:userBean");
if (_id != null)
printXmlAttribute(os, "id", _id);
if (_typeName != null)
printXmlAttribute(os, "type", _typeName);
if (_className != null)
printXmlAttribute(os, "class", _className);
if (_beanName != null)
printXmlAttribute(os, "beanName", _beanName);
if (_scope != null)
printXmlAttribute(os, "scope", _scope);
os.print("/>");
}
/**
* Generates the code for the scriptlet
*
* @param out the output writer for the generated java.
*/
public void generate(JspJavaWriter out)
throws Exception
{
if (_id == null)
throw error(L.l("<jsp:useBean> expects an 'id' attribute. id specifies the variable name for the bean."));
if (_typeName == null)
_typeName = _className;
if (_typeName == null)
throw error(L.l("<jsp:useBean> expects a 'type' or 'class' attribute. The 'type' specifies the Java type of the bean."));
// Save the bean's type
_gen.addBeanClass(_id, _typeName);
String context = null;
if (_scope == null || _scope.equals("page"))
context = "pageContext";
else if (_scope.equals("request")) {
context = "pageContext.getRequest()";
}
else if (_scope.equals("session")) {
context = "pageContext.getSession()";
}
else if (_scope.equals("application")) {
context = "pageContext.getApplication()";
}
else
throw error(L.l("Unknown scope '{0}' in <jsp:useBean>. Scope must be 'page', 'request', 'session', or 'application'.", _scope));
// declare the bean
out.println(_typeName + " " + _id + ";");
// application and session beans need synchronization
if ("application".equals(_scope) || "session".equals(_scope)) {
out.println("synchronized (" + context + ") {");
out.pushDepth();
}
// try to get the bean from the context
out.print(_id + " = (" + _typeName + ") " + context);
out.println(".getAttribute(\"" + _id + "\");");
// If the bean is new, then instantiate it
out.println("if (" + _id + " == null) {");
out.pushDepth();
boolean canInstantiate = false;
// instantiate a class
if (_className != null) {
String msg = canInstantiateBean(_className);
if (msg == null) {
out.println(_id + " = new " + _className + "();");
canInstantiate = true;
}
else
out.println("throw new java.lang.InstantiationException(\"" + msg + "\");");
}
else if (_beanName == null)
out.println("throw new java.lang.InstantiationException(\"jsp:useBean needs 'bean' or 'class'\");");
// instantiate beans with a request time attribute
else if (hasRuntimeAttribute(_beanName)) {
String beanName = getRuntimeAttribute(_beanName);
out.println(_id + " = (" + _typeName +
") java.beans.Beans.instantiate(getClass().getClassLoader(), " +
beanName + ");");
canInstantiate = true;
}
// instantiate a beans
else {
out.println(_id + " = (" + _typeName +
") java.beans.Beans.instantiate(getClass().getClassLoader(), \"" +
_beanName + "\");");
canInstantiate = true;
}
// Save it in the context
if (! canInstantiate) {
}
else
out.println(context + ".setAttribute(\"" + _id + "\", " + _id + ");");
// Initialize the new bean
if (canInstantiate)
generateChildren(out);
out.popDepth();
out.println("}");
// Close the synchronization if necessary
if ("application".equals(_scope) || "session".equals(_scope)) {
out.popDepth();
out.println("}");
}
}
/**
* Tests if the bean can be instantiated.
*/
private String canInstantiateBean(String className)
throws Exception
{
try {
Class cl = _gen.getBeanClass(className);
int modifiers = cl.getModifiers();
if (Modifier.isInterface(modifiers))
return L.l("'{0}' is an interface", className);
if (Modifier.isAbstract(modifiers))
return L.l("'{0}' is abstract", className);
if (! Modifier.isPublic(modifiers))
return L.l("'{0}' must be public", className);
Constructor []constructors = cl.getConstructors();
for (int i = 0; i < constructors.length; i++) {
Class []param = constructors[i].getParameterTypes();
if (param.length == 0)
return null;
}
} catch (Exception e) {
throw error(e.getMessage());
}
return L.l("'{0}' has no public zero-arg constructor", className);
}
}