org.tinygroup.jspengine.compiler.ELFunctionMapper Maven / Gradle / Ivy
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/**
* Copyright (c) 1997-2013, www.tinygroup.org ([email protected]).
*
* Licensed under the GPL, Version 3.0 (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.gnu.org/licenses/gpl.html
*
* 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.tinygroup.jspengine.compiler;
import org.tinygroup.jspengine.JasperException;
import org.tinygroup.jspengine.runtime.ProtectedFunctionMapper;
import javax.servlet.jsp.tagext.FunctionInfo;
import java.util.ArrayList;
import java.util.HashMap;
/**
* This class generates functions mappers for the EL expressions in the page.
* Instead of a global mapper, a mapper is used for ecah call to EL evaluator,
* thus avoiding the prefix overlapping and redefinition issues.
*
* @author Kin-man Chung
*/
public class ELFunctionMapper {
private int currFunc = 0;
StringBuffer ds; // Contains codes to initialize the functions mappers.
StringBuffer ss; // Contains declarations of the functions mappers.
/**
* Creates the functions mappers for all EL expressions in the JSP page.
*
* @param compiler
* Current compiler, mainly for accessing error dispatcher.
* @param page
* The current compilation unit.
*/
public static void map(Compiler compiler, Node.Nodes page)
throws JasperException {
ELFunctionMapper map = new ELFunctionMapper();
map.ds = new StringBuffer();
map.ss = new StringBuffer();
page.visit(map.new ELFunctionVisitor());
// Append the declarations to the root node
String ds = map.ds.toString();
if (ds.length() > 0) {
Node root = page.getRoot();
new Node.Declaration(map.ss.toString(), null, root);
new Node.Declaration("static {\n" + ds + "}\n", null, root);
}
}
/**
* A visitor for the page. The places where EL is allowed are scanned for
* functions, and if found functions mappers are created.
*/
class ELFunctionVisitor extends Node.Visitor {
/**
* Use a global name map to facilitate reuse of function maps. The key
* used is prefix:function:uri.
*/
private HashMap gMap = new HashMap();
public void visit(Node.ParamAction n) throws JasperException {
doMap(n.getValue());
visitBody(n);
}
public void visit(Node.IncludeAction n) throws JasperException {
doMap(n.getPage());
visitBody(n);
}
public void visit(Node.ForwardAction n) throws JasperException {
doMap(n.getPage());
visitBody(n);
}
public void visit(Node.SetProperty n) throws JasperException {
doMap(n.getValue());
visitBody(n);
}
public void visit(Node.UseBean n) throws JasperException {
doMap(n.getBeanName());
visitBody(n);
}
public void visit(Node.PlugIn n) throws JasperException {
doMap(n.getHeight());
doMap(n.getWidth());
visitBody(n);
}
public void visit(Node.JspElement n) throws JasperException {
Node.JspAttribute[] attrs = n.getJspAttributes();
for (int i = 0; attrs != null && i < attrs.length; i++) {
doMap(attrs[i]);
}
doMap(n.getNameAttribute());
visitBody(n);
}
public void visit(Node.UninterpretedTag n) throws JasperException {
Node.JspAttribute[] attrs = n.getJspAttributes();
for (int i = 0; attrs != null && i < attrs.length; i++) {
doMap(attrs[i]);
}
visitBody(n);
}
public void visit(Node.CustomTag n) throws JasperException {
Node.JspAttribute[] attrs = n.getJspAttributes();
for (int i = 0; attrs != null && i < attrs.length; i++) {
doMap(attrs[i]);
}
visitBody(n);
}
public void visit(Node.ELExpression n) throws JasperException {
doMap(n.getEL());
}
private void doMap(Node.JspAttribute attr) throws JasperException {
if (attr != null) {
doMap(attr.getEL());
}
}
/**
* Creates function mappers, if needed, from ELNodes
*/
private void doMap(ELNode.Nodes el) throws JasperException {
// Only care about functions in ELNode's
class Fvisitor extends ELNode.Visitor {
ArrayList funcs = new ArrayList();
HashMap keyMap = new HashMap();
public void visit(ELNode.Function n) throws JasperException {
String key = n.getPrefix() + ":" + n.getName();
if (!keyMap.containsKey(key)) {
keyMap.put(key, "");
funcs.add(n);
}
}
}
if (el == null) {
return;
}
// First locate all unique functions in this EL
Fvisitor fv = new Fvisitor();
el.visit(fv);
ArrayList functions = fv.funcs;
if (functions.size() == 0) {
return;
}
// Reuse a previous map if possible
String decName = matchMap(functions);
if (decName != null) {
el.setMapName(decName);
return;
}
// Generate declaration for the map statically
decName = getMapName();
ss.append("static private "
+ ProtectedFunctionMapper.class.getName() + " " + decName
+ ";\n");
ds.append(" " + decName + "= ");
ds.append(ProtectedFunctionMapper.class.getName());
// Special case if there is only one function in the map
String funcMethod = null;
if (functions.size() == 1) {
funcMethod = ".getMapForFunction";
} else {
ds.append(".getInstance();\n");
funcMethod = " " + decName + ".mapFunction";
}
// Setup arguments for either getMapForFunction or mapFunction
for (int i = 0; i < functions.size(); i++) {
ELNode.Function f = (ELNode.Function) functions.get(i);
FunctionInfo funcInfo = f.getFunctionInfo();
String key = f.getPrefix() + ":" + f.getName();
ds.append(funcMethod + "(\"" + key + "\", "
+ funcInfo.getFunctionClass() + ".class, " + '\"'
+ f.getMethodName() + "\", " + "new Class[] {");
String params[] = f.getParameters();
for (int k = 0; k < params.length; k++) {
if (k != 0) {
ds.append(", ");
}
int iArray = params[k].indexOf('[');
if (iArray < 0) {
ds.append(params[k] + ".class");
} else {
String baseType = params[k].substring(0, iArray);
ds.append("java.lang.reflect.Array.newInstance(");
ds.append(baseType);
ds.append(".class,");
// Count the number of array dimension
int aCount = 0;
for (int jj = iArray; jj < params[k].length(); jj++) {
if (params[k].charAt(jj) == '[') {
aCount++;
}
}
if (aCount == 1) {
ds.append("0).getClass()");
} else {
ds.append("new int[" + aCount + "]).getClass()");
}
}
}
ds.append("});\n");
// Put the current name in the global function map
gMap.put(f.getPrefix() + ':' + f.getName() + ':' + f.getUri(),
decName);
}
el.setMapName(decName);
}
/**
* Find the name of the function mapper for an EL. Reuse a previously
* generated one if possible.
*
* @param functions
* An ArrayList of ELNode.Function instances that represents
* the functions in an EL
* @return A previous generated function mapper name that can be used by
* this EL; null if none found.
*/
private String matchMap(ArrayList functions) {
String mapName = null;
for (int i = 0; i < functions.size(); i++) {
ELNode.Function f = (ELNode.Function) functions.get(i);
String temName = (String) gMap.get(f.getPrefix() + ':'
+ f.getName() + ':' + f.getUri());
if (temName == null) {
return null;
}
if (mapName == null) {
mapName = temName;
} else if (!temName.equals(mapName)) {
// If not all in the previous match, then no match.
return null;
}
}
return mapName;
}
/*
* @return An unique name for a function mapper.
*/
private String getMapName() {
return "_jspx_fnmap_" + currFunc++;
}
}
}
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