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EE4J Compatible Implementation for Jakarta Faces API
/*
* Copyright (c) 1997, 2020 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package com.sun.faces.application;
import static com.sun.faces.util.Util.isAnyNull;
import static com.sun.faces.util.Util.loadClass2;
import static com.sun.faces.util.Util.newInstance;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.util.Arrays;
import jakarta.el.ELContext;
import jakarta.el.ELException;
import jakarta.el.ExpressionFactory;
import jakarta.el.MethodExpression;
import jakarta.el.MethodInfo;
import jakarta.el.ValueExpression;
import jakarta.faces.component.StateHolder;
import jakarta.faces.context.FacesContext;
import jakarta.faces.el.MethodBinding;
/**
*
* Wrap a MethodBinding instance and expose it as a MethodExpression.
*
*/
public class MethodExpressionMethodBindingAdapter extends MethodExpression implements Serializable, StateHolder {
private static final long serialVersionUID = 5639227653537610567L;
public MethodExpressionMethodBindingAdapter() {
} // for StateHolder
private MethodBinding binding = null;
public MethodExpressionMethodBindingAdapter(MethodBinding binding) {
assert null != binding;
this.binding = binding;
}
//
// Methods from MethodExpression
//
private transient MethodInfo info = null;
@Override
public MethodInfo getMethodInfo(ELContext context) throws ELException {
assert null != binding;
if (context == null) {
throw new NullPointerException("ELContext -> null");
}
if (null == info) {
FacesContext facesContext = (FacesContext) context.getContext(FacesContext.class);
if (null != facesContext) {
try {
// PENDING - we should find a way to provide more information
info = new MethodInfo(null, binding.getType(facesContext), null);
} catch (Exception e) {
throw new ELException(e);
}
}
}
return info;
}
@Override
public Object invoke(ELContext context, Object[] params) throws ELException {
assert null != binding;
if (context == null) {
throw new NullPointerException("ELContext -> null");
}
Object result = null;
FacesContext facesContext = (FacesContext) context.getContext(FacesContext.class);
if (null != facesContext) {
try {
result = binding.invoke(facesContext, params);
} catch (Exception e) {
throw new ELException(e);
}
}
return result;
}
@Override
public String getExpressionString() {
assert null != binding;
return binding.getExpressionString();
}
@Override
public boolean isLiteralText() {
assert binding != null;
String expr = binding.getExpressionString();
return !(expr.startsWith("#{") && expr.endsWith("}"));
}
@Override
public boolean equals(Object other) {
if (other == this) {
return true;
}
if (other instanceof MethodExpressionMethodBindingAdapter) {
MethodBinding ob = ((MethodExpressionMethodBindingAdapter) other).getWrapped();
return binding.equals(ob);
} else if (other instanceof MethodExpression) {
MethodExpression expression = (MethodExpression) other;
// We'll need to do a little leg work to determine
// if the MethodBinding is equivalent to the
// wrapped MethodExpression
String expr = binding.getExpressionString();
int idx = expr.indexOf('.');
String target = expr.substring(0, idx).substring(2);
String t = expr.substring(idx + 1);
String method = t.substring(0, t.length() - 1);
FacesContext context = FacesContext.getCurrentInstance();
ELContext elContext = context.getELContext();
MethodInfo controlInfo = expression.getMethodInfo(elContext);
// ensure the method names are the same
if (!controlInfo.getName().equals(method)) {
return false;
}
// Using the target, create an expression and evaluate
// it.
ExpressionFactory factory = context.getApplication().getExpressionFactory();
ValueExpression ve = factory.createValueExpression(elContext, "#{" + target + '}', Object.class);
if (ve == null) {
return false;
}
Object result = ve.getValue(elContext);
if (result == null) {
return false;
}
// Get all of the methods with the matching name and try
// to find a match based on controlInfo's return and parameter
// types
Method[] methods = result.getClass().getMethods();
for (Method meth : methods) {
if (meth.getName().equals(method) && meth.getReturnType().equals(controlInfo.getReturnType())
&& Arrays.equals(meth.getParameterTypes(), controlInfo.getParamTypes())) {
return true;
}
}
}
return false;
}
@Override
public int hashCode() {
assert null != binding;
return binding.hashCode();
}
public String getDelimiterSyntax() {
// PENDING (visvan) Implementation
return "";
}
//
// Methods from StateHolder
//
@Override
public Object saveState(FacesContext context) {
if (context == null) {
throw new NullPointerException();
}
Object result = null;
if (!tranzient) {
if (binding instanceof StateHolder) {
Object[] stateStruct = new Object[2];
// save the actual state of our wrapped binding
stateStruct[0] = ((StateHolder) binding).saveState(context);
// save the class name of the binding impl
stateStruct[1] = binding.getClass().getName();
result = stateStruct;
} else {
result = binding;
}
}
return result;
}
@Override
public void restoreState(FacesContext context, Object state) {
if (context == null) {
throw new NullPointerException();
}
if (null == state) {
return;
}
if (!(state instanceof MethodBinding)) {
Object[] stateStruct = (Object[]) state;
Object savedState = stateStruct[0];
String className = stateStruct[1].toString();
MethodBinding result = null;
if (className != null) {
Class toRestoreClass = loadClass2(className, this);
if (toRestoreClass != null) {
result = newInstance(toRestoreClass);
}
if (!isAnyNull(result, savedState)) {
// don't need to check transient, since that was
// done on the saving side.
((StateHolder) result).restoreState(context, savedState);
}
binding = result;
}
} else {
binding = (MethodBinding) state;
}
}
private boolean tranzient = false;
@Override
public boolean isTransient() {
return tranzient;
}
@Override
public void setTransient(boolean newTransientMethod) {
tranzient = newTransientMethod;
}
//
// methods used by classes aware of this class's wrapper nature
//
public MethodBinding getWrapped() {
return binding;
}
}