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feilong is a suite of core and expanded libraries that include utility classes, http, excel,cvs, io classes, and much much more.
package com.feilong.lib.ognl.enhance;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import com.feilong.lib.javassist.CannotCompileException;
import com.feilong.lib.javassist.ClassPool;
import com.feilong.lib.javassist.CtClass;
import com.feilong.lib.javassist.CtField;
import com.feilong.lib.javassist.CtMethod;
import com.feilong.lib.javassist.LoaderClassPath;
import com.feilong.lib.javassist.NotFoundException;
import com.feilong.lib.ognl.ASTAnd;
import com.feilong.lib.ognl.ASTChain;
import com.feilong.lib.ognl.ASTConst;
import com.feilong.lib.ognl.ASTCtor;
import com.feilong.lib.ognl.ASTList;
import com.feilong.lib.ognl.ASTMethod;
import com.feilong.lib.ognl.ASTOr;
import com.feilong.lib.ognl.ASTProperty;
import com.feilong.lib.ognl.ASTRootVarRef;
import com.feilong.lib.ognl.ASTStaticField;
import com.feilong.lib.ognl.ASTStaticMethod;
import com.feilong.lib.ognl.ASTThisVarRef;
import com.feilong.lib.ognl.ASTVarRef;
import com.feilong.lib.ognl.ExpressionNode;
import com.feilong.lib.ognl.Node;
import com.feilong.lib.ognl.OgnlContext;
import com.feilong.lib.ognl.OgnlRuntime;
/**
* Responsible for managing/providing functionality related to compiling generated java source
* expressions via bytecode enhancements for a given ognl expression.
*/
public class ExpressionCompiler implements OgnlExpressionCompiler{
/**
* Key used to store any java source string casting statements in the {@link OgnlContext} during
* class compilation.
*/
public static final String PRE_CAST = "_preCast";
/**
* {@link ClassLoader} instances.
*/
protected Map _loaders = new HashMap();
/**
* Javassist class definition poool.
*/
protected ClassPool _pool;
protected int _classCounter = 0;
/**
* Default constructor, does nothing.
*/
public ExpressionCompiler(){
}
/**
* Used by {@link #castExpression(com.feilong.lib.ognl.OgnlContext, com.feilong.lib.ognl.Node, String)} to store the cast java
* source string in to the current {@link OgnlContext}. This will either add to the existing
* string present if it already exists or create a new instance and store it using the static key
* of {@link #PRE_CAST}.
*
* @param context
* The current execution context.
* @param cast
* The java source string to store in to the context.
*/
public static void addCastString(OgnlContext context,String cast){
String value = (String) context.get(PRE_CAST);
if (value != null){
value = cast + value;
}else{
value = cast;
}
context.put(PRE_CAST, value);
}
/**
* Returns the appropriate casting expression (minus parens) for the specified class type.
*
*
* For instance, if given an {@link Integer} object the string "java.lang.Integer"
* would be returned. For an array of primitive ints "int[]" and so on..
*
*
* @param type
* The class to cast a string expression for.
* @return The converted raw string version of the class name.
*/
public static String getCastString(Class type){
if (type == null){
return null;
}
return type.isArray() ? type.getComponentType().getName() + "[]" : type.getName();
}
/**
* Convenience method called by many different property/method resolving AST types to get a root expression
* resolving string for the given node. The callers are mostly ignorant and rely on this method to properly
* determine if the expression should be cast at all and take the appropriate actions if it should.
*
* @param expression
* The node to check and generate a root expression to if necessary.
* @param root
* The root object for this execution.
* @param context
* The current execution context.
* @return Either an empty string or a root path java source string compatible with javassist compilations
* from the root object up to the specified {@link Node}.
*/
public static String getRootExpression(Node expression,Object root,OgnlContext context){
String rootExpr = "";
if (!shouldCast(expression)){
return rootExpr;
}
if ((!ASTList.class.isInstance(expression) && !ASTVarRef.class.isInstance(expression)
&& !ASTStaticMethod.class.isInstance(expression) && !ASTStaticField.class.isInstance(expression)
&& !ASTConst.class.isInstance(expression) && !ExpressionNode.class.isInstance(expression)
&& !ASTCtor.class.isInstance(expression) && !ASTStaticMethod.class.isInstance(expression) && root != null)
|| (root != null && ASTRootVarRef.class.isInstance(expression))){
Class castClass = OgnlRuntime.getCompiler().getRootExpressionClass(expression, context);
if (castClass.isArray() || ASTRootVarRef.class.isInstance(expression) || ASTThisVarRef.class.isInstance(expression)){
rootExpr = "((" + getCastString(castClass) + ")$2)";
if (ASTProperty.class.isInstance(expression) && !((ASTProperty) expression).isIndexedAccess()){
rootExpr += ".";
}
}else if ((ASTProperty.class.isInstance(expression) && ((ASTProperty) expression).isIndexedAccess())
|| ASTChain.class.isInstance(expression)){
rootExpr = "((" + getCastString(castClass) + ")$2)";
}else{
rootExpr = "((" + getCastString(castClass) + ")$2).";
}
}
return rootExpr;
}
/**
* Used by {@link #getRootExpression(com.feilong.lib.ognl.Node, Object, com.feilong.lib.ognl.OgnlContext)} to determine if the
* expression
* needs to be cast at all.
*
* @param expression
* The node to check against.
* @return Yes if the node type should be cast - false otherwise.
*/
public static boolean shouldCast(Node expression){
if (ASTChain.class.isInstance(expression)){
Node child = expression.jjtGetChild(0);
if (ASTConst.class.isInstance(child) || ASTStaticMethod.class.isInstance(child) || ASTStaticField.class.isInstance(child)
|| (ASTVarRef.class.isInstance(child) && !ASTRootVarRef.class.isInstance(child))){
return false;
}
}
return !ASTConst.class.isInstance(expression);
}
@Override
public String castExpression(OgnlContext context,Node expression,String body){
// ok - so this looks really f-ed up ...and it is ..eh if you can do it better I'm all for it :)
if (context.getCurrentAccessor() == null || context.getPreviousType() == null
|| context.getCurrentAccessor().isAssignableFrom(context.getPreviousType())
|| (context.getCurrentType() != null && context.getCurrentObject() != null
&& context.getCurrentType().isAssignableFrom(context.getCurrentObject().getClass())
&& context.getCurrentAccessor().isAssignableFrom(context.getPreviousType()))
|| body == null || body.trim().length() < 1
|| (context.getCurrentType() != null && context.getCurrentType().isArray()
&& (context.getPreviousType() == null || context.getPreviousType() != Object.class))
|| ASTOr.class.isInstance(expression) || ASTAnd.class.isInstance(expression)
|| ASTRootVarRef.class.isInstance(expression) || context.getCurrentAccessor() == Class.class
|| (context.get(ExpressionCompiler.PRE_CAST) != null
&& ((String) context.get(ExpressionCompiler.PRE_CAST)).startsWith("new"))
|| ASTStaticField.class.isInstance(expression) || ASTStaticMethod.class.isInstance(expression)
|| (OrderedReturn.class.isInstance(expression) && ((OrderedReturn) expression).getLastExpression() != null)){
return body;
}
ExpressionCompiler.addCastString(context, "((" + ExpressionCompiler.getCastString(context.getCurrentAccessor()) + ")");
return ")" + body;
}
@Override
public String getClassName(Class clazz){
if (clazz.getName().equals("java.util.AbstractList$Itr")){
return Iterator.class.getName();
}
if (Modifier.isPublic(clazz.getModifiers()) && clazz.isInterface()){
return clazz.getName();
}
return _getClassName(clazz, clazz.getInterfaces());
}
private String _getClassName(Class clazz,Class[] intf){
for (Class element : intf){
if (element.getName().indexOf("util.List") > 0){
return element.getName();
}else if (element.getName().indexOf("Iterator") > 0){
return element.getName();
}
}
final Class superclazz = clazz.getSuperclass();
if (superclazz != null){
final Class[] superclazzIntf = superclazz.getInterfaces();
if (superclazzIntf.length > 0){
return _getClassName(superclazz, superclazzIntf);
}
}
return clazz.getName();
}
@Override
public Class getSuperOrInterfaceClass(Method m,Class clazz){
Class[] intfs = clazz.getInterfaces();
if (intfs != null && intfs.length > 0){
Class intClass;
for (Class intf : intfs){
intClass = getSuperOrInterfaceClass(m, intf);
if (intClass != null){
return intClass;
}
if (Modifier.isPublic(intf.getModifiers()) && containsMethod(m, intf)){
return intf;
}
}
}
if (clazz.getSuperclass() != null){
Class superClass = getSuperOrInterfaceClass(m, clazz.getSuperclass());
if (superClass != null){
return superClass;
}
}
if (Modifier.isPublic(clazz.getModifiers()) && containsMethod(m, clazz)){
return clazz;
}
return null;
}
/**
* Helper utility method used by compiler to help resolve class->method mappings
* during method calls to {@link OgnlExpressionCompiler#getSuperOrInterfaceClass(java.lang.reflect.Method, Class)}.
*
* @param m
* The method to check for existance of.
* @param clazz
* The class to check for the existance of a matching method definition to the method passed in.
* @return True if the class contains the specified method, false otherwise.
*/
public boolean containsMethod(Method m,Class clazz){
Method[] methods = clazz.getMethods();
if (methods == null){
return false;
}
for (Method method : methods){
if (method.getName().equals(m.getName()) && method.getReturnType() == m.getReturnType()){
Class[] parms = m.getParameterTypes();
if (parms == null){
continue;
}
Class[] mparms = method.getParameterTypes();
if (mparms == null || mparms.length != parms.length){
continue;
}
boolean parmsMatch = true;
for (int p = 0; p < parms.length; p++){
if (parms[p] != mparms[p]){
parmsMatch = false;
break;
}
}
if (!parmsMatch){
continue;
}
Class[] exceptions = m.getExceptionTypes();
if (exceptions == null){
continue;
}
Class[] mexceptions = method.getExceptionTypes();
if (mexceptions == null || mexceptions.length != exceptions.length){
continue;
}
boolean exceptionsMatch = true;
for (int e = 0; e < exceptions.length; e++){
if (exceptions[e] != mexceptions[e]){
exceptionsMatch = false;
break;
}
}
if (!exceptionsMatch){
continue;
}
return true;
}
}
return false;
}
@Override
public Class getInterfaceClass(Class clazz){
if (clazz.getName().equals("java.util.AbstractList$Itr")){
return Iterator.class;
}
if (Modifier.isPublic(clazz.getModifiers()) && clazz.isInterface() || clazz.isPrimitive()){
return clazz;
}
return _getInterfaceClass(clazz, clazz.getInterfaces());
}
private Class _getInterfaceClass(Class clazz,Class[] intf){
for (Class element : intf){
if (List.class.isAssignableFrom(element)){
return List.class;
}else if (Iterator.class.isAssignableFrom(element)){
return Iterator.class;
}else if (Map.class.isAssignableFrom(element)){
return Map.class;
}else if (Set.class.isAssignableFrom(element)){
return Set.class;
}else if (Collection.class.isAssignableFrom(element)){
return Collection.class;
}
}
final Class superclazz = clazz.getSuperclass();
if (superclazz != null){
final Class[] superclazzIntf = superclazz.getInterfaces();
if (superclazzIntf.length > 0){
return _getInterfaceClass(superclazz, superclazzIntf);
}
}
return clazz;
}
@Override
public Class getRootExpressionClass(Node rootNode,OgnlContext context){
if (context.getRoot() == null){
return null;
}
Class ret = context.getRoot().getClass();
if (context.getFirstAccessor() != null && context.getFirstAccessor().isInstance(context.getRoot())){
ret = context.getFirstAccessor();
}
return ret;
}
protected String generateGetter(
OgnlContext context,
CtClass newClass,
CtClass objClass,
ClassPool pool,
CtMethod valueGetter,
Node expression,
Object root) throws Exception{
String pre = "";
String post = "";
String body;
context.setRoot(root);
// the ExpressionAccessor API has to reference the generic Object class for get/set operations, so this sets up that known
// type beforehand
context.remove(PRE_CAST);
// Recursively generate the java source code representation of the top level expression
String getterCode = expression.toGetSourceString(context, root);
if (getterCode == null || getterCode.trim().length() <= 0 && !ASTVarRef.class.isAssignableFrom(expression.getClass())){
getterCode = "null";
}
String castExpression = (String) context.get(PRE_CAST);
if (context.getCurrentType() == null || context.getCurrentType().isPrimitive()
|| Character.class.isAssignableFrom(context.getCurrentType()) || Object.class == context.getCurrentType()){
pre = pre + " ($w) (";
post = post + ")";
}
String rootExpr = !getterCode.equals("null") ? getRootExpression(expression, root, context) : "";
String noRoot = (String) context.remove("_noRoot");
if (noRoot != null){
rootExpr = "";
}
createLocalReferences(context, pool, newClass, objClass, valueGetter.getParameterTypes());
if (OrderedReturn.class.isInstance(expression) && ((OrderedReturn) expression).getLastExpression() != null){
body = "{ " + (ASTMethod.class.isInstance(expression) || ASTChain.class.isInstance(expression) ? rootExpr : "")
+ (castExpression != null ? castExpression : "") + ((OrderedReturn) expression).getCoreExpression() + " return "
+ pre + ((OrderedReturn) expression).getLastExpression() + post + ";}";
}else{
body = "{ return " + pre + (castExpression != null ? castExpression : "") + rootExpr + getterCode + post + ";}";
}
if (body.indexOf("..") >= 0){
body = body.replaceAll("\\.\\.", ".");
}
valueGetter.setBody(body);
newClass.addMethod(valueGetter);
return body;
}
@Override
public String createLocalReference(OgnlContext context,String expression,Class type){
String referenceName = "ref" + context.incrementLocalReferenceCounter();
context.addLocalReference(referenceName, new LocalReferenceImpl(referenceName, expression, type));
String castString = "";
if (!type.isPrimitive()){
castString = "(" + ExpressionCompiler.getCastString(type) + ") ";
}
return castString + referenceName + "($$)";
}
void createLocalReferences(OgnlContext context,ClassPool pool,CtClass clazz,CtClass objClass,CtClass[] params)
throws CannotCompileException,NotFoundException{
Map referenceMap = context.getLocalReferences();
if (referenceMap == null || referenceMap.size() < 1){
return;
}
Iterator it = referenceMap.values().iterator();
while (it.hasNext()){
LocalReference ref = (LocalReference) it.next();
String widener = ref.getType().isPrimitive() ? " " : " ($w) ";
String body = "{";
body += " return " + widener + ref.getExpression() + ";";
body += "}";
if (body.indexOf("..") >= 0){
body = body.replaceAll("\\.\\.", ".");
}
CtMethod ctMethod = new CtMethod(pool.get(getCastString(ref.getType())), ref.getName(), params, clazz);
ctMethod.setBody(body);
clazz.addMethod(ctMethod);
it.remove();
}
}
protected String generateSetter(
OgnlContext context,
CtClass newClass,
CtClass objClass,
ClassPool pool,
CtMethod valueSetter,
Node expression,
Object root) throws Exception{
if (ExpressionNode.class.isInstance(expression) || ASTConst.class.isInstance(expression)){
throw new UnsupportedCompilationException("Can't compile expression/constant setters.");
}
context.setRoot(root);
context.remove(PRE_CAST);
String body;
String setterCode = expression.toSetSourceString(context, root);
String castExpression = (String) context.get(PRE_CAST);
if (setterCode == null || setterCode.trim().length() < 1){
throw new UnsupportedCompilationException("Can't compile null setter body.");
}
if (root == null){
throw new UnsupportedCompilationException("Can't compile setters with a null root object.");
}
String pre = getRootExpression(expression, root, context);
String noRoot = (String) context.remove("_noRoot");
if (noRoot != null){
pre = "";
}
createLocalReferences(context, pool, newClass, objClass, valueSetter.getParameterTypes());
body = "{" + (castExpression != null ? castExpression : "") + pre + setterCode + ";}";
if (body.indexOf("..") >= 0){
body = body.replaceAll("\\.\\.", ".");
}
valueSetter.setBody(body);
newClass.addMethod(valueSetter);
return body;
}
/**
* Fail safe getter creation when normal compilation fails.
*
* @param clazz
* The javassist class the new method should be attached to.
* @param valueGetter
* The method definition the generated code will be contained within.
* @param node
* The root expression node.
* @return The generated source string for this method, the method will still be
* added via the javassist API either way so this is really a convenience
* for exception reporting / debugging.
* @throws Exception
* If a javassist error occurs.
*/
protected String generateOgnlGetter(CtClass clazz,CtMethod valueGetter,CtField node) throws Exception{
String body = "return " + node.getName() + ".getValue($1, $2);";
valueGetter.setBody(body);
clazz.addMethod(valueGetter);
return body;
}
/**
* Fail safe setter creation when normal compilation fails.
*
* @param clazz
* The javassist class the new method should be attached to.
* @param valueSetter
* The method definition the generated code will be contained within.
* @param node
* The root expression node.
* @return The generated source string for this method, the method will still be
* added via the javassist API either way so this is really a convenience
* for exception reporting / debugging.
* @throws Exception
* If a javassist error occurs.
*/
protected String generateOgnlSetter(CtClass clazz,CtMethod valueSetter,CtField node) throws Exception{
String body = node.getName() + ".setValue($1, $2, $3);";
valueSetter.setBody(body);
clazz.addMethod(valueSetter);
return body;
}
/**
* Creates a {@link ClassLoader} instance compatible with the javassist classloader and normal
* OGNL class resolving semantics.
*
* @param context
* The current execution context.
*
* @return The created {@link ClassLoader} instance.
*/
protected EnhancedClassLoader getClassLoader(OgnlContext context){
EnhancedClassLoader ret = (EnhancedClassLoader) _loaders.get(context.getClassResolver());
if (ret != null){
return ret;
}
ClassLoader classLoader = new ContextClassLoader(OgnlContext.class.getClassLoader(), context);
ret = new EnhancedClassLoader(classLoader);
_loaders.put(context.getClassResolver(), ret);
return ret;
}
/**
* Loads a new class definition via javassist for the specified class.
*
* @param searchClass
* The class to load.
* @return The javassist class equivalent.
*
* @throws NotFoundException
* When the class definition can't be found.
*/
private CtClass getCtClass(Class searchClass) throws NotFoundException{
return _pool.get(searchClass.getName());
}
/**
* Gets either a new or existing {@link ClassPool} for use in compiling javassist
* classes. A new class path object is inserted in to the returned {@link ClassPool} using
* the passed in loader instance if a new pool needs to be created.
*
* @param context
* The current execution context.
* @param loader
* The {@link ClassLoader} instance to use - as returned by {@link #getClassLoader(com.feilong.lib.ognl.OgnlContext)}.
* @return The existing or new {@link ClassPool} instance.
*/
protected ClassPool getClassPool(OgnlContext context,EnhancedClassLoader loader){
if (_pool != null){
return _pool;
}
_pool = ClassPool.getDefault();
_pool.insertClassPath(new LoaderClassPath(loader.getParent()));
return _pool;
}
}
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