org.jboss.seam.faces.component.MethodBindingMethodExpressionAdapter Maven / Gradle / Ivy
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* Copyright 2010, Red Hat, Inc., and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.seam.faces.component;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.util.Arrays;
import javax.el.ELContext;
import javax.el.ELException;
import javax.el.ExpressionFactory;
import javax.el.MethodExpression;
import javax.el.MethodInfo;
import javax.el.ValueExpression;
import javax.faces.component.StateHolder;
import javax.faces.context.FacesContext;
import javax.faces.el.EvaluationException;
import javax.faces.el.MethodBinding;
import javax.faces.el.MethodNotFoundException;
/**
*
* Wrap a MethodExpression instance and expose it as a MethodBinding
*
*
*/
class MethodBindingMethodExpressionAdapter extends MethodBinding implements StateHolder, Serializable
{
private static final long serialVersionUID = 7334926223014401689L;
private MethodExpression methodExpression = null;
private boolean tranzient;
public MethodBindingMethodExpressionAdapter()
{
} // for StateHolder
MethodBindingMethodExpressionAdapter(final MethodExpression methodExpression)
{
this.methodExpression = methodExpression;
}
@Override
@SuppressWarnings("deprecation")
public Object invoke(final FacesContext context, final Object params[]) throws EvaluationException, MethodNotFoundException
{
assert (null != methodExpression);
if (context == null)
{
throw new NullPointerException("FacesConext -> null");
}
Object result = null;
try
{
result = methodExpression.invoke(context.getELContext(), params);
}
catch (javax.el.MethodNotFoundException e)
{
throw new javax.faces.el.MethodNotFoundException(e);
}
catch (javax.el.PropertyNotFoundException e)
{
throw new EvaluationException(e);
}
catch (ELException e)
{
Throwable cause = e.getCause();
if (cause == null)
{
cause = e;
}
throw new EvaluationException(cause);
}
catch (NullPointerException e)
{
throw new MethodNotFoundException(e);
}
return result;
}
@Override
@SuppressWarnings("deprecation")
public Class getType(final FacesContext context) throws MethodNotFoundException
{
assert (null != methodExpression);
if (context == null)
{
throw new NullPointerException("FacesConext -> null");
}
Class result = null;
if (context == null)
{
throw new NullPointerException();
}
try
{
MethodInfo mi = methodExpression.getMethodInfo(context.getELContext());
result = mi.getReturnType();
}
catch (javax.el.PropertyNotFoundException e)
{
throw new MethodNotFoundException(e);
}
catch (javax.el.MethodNotFoundException e)
{
throw new MethodNotFoundException(e);
}
catch (ELException e)
{
throw new MethodNotFoundException(e);
}
return result;
}
@Override
public String getExpressionString()
{
assert (null != methodExpression);
return methodExpression.getExpressionString();
}
@Override
@SuppressWarnings("deprecation")
public boolean equals(final Object other)
{
if (this == other)
{
return true;
}
if (other instanceof MethodBindingMethodExpressionAdapter)
{
return methodExpression.equals(((MethodBindingMethodExpressionAdapter) other).getWrapped());
}
else if (other instanceof MethodBinding)
{
MethodBinding binding = (MethodBinding) 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 = methodExpression.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
Class type = binding.getType(context);
Method[] methods = result.getClass().getMethods();
for (Method meth : methods)
{
if (meth.getName().equals(method) && type.equals(controlInfo.getReturnType()) && Arrays.equals(meth.getParameterTypes(), controlInfo.getParamTypes()))
{
return true;
}
}
}
return false;
}
@Override
public int hashCode()
{
assert (null != methodExpression);
return methodExpression.hashCode();
}
public boolean isTransient()
{
return this.tranzient;
}
public void setTransient(final boolean tranzient)
{
this.tranzient = tranzient;
}
public Object saveState(final FacesContext context)
{
if (context == null)
{
throw new NullPointerException();
}
Object result = null;
if (!tranzient)
{
if (methodExpression instanceof StateHolder)
{
Object[] stateStruct = new Object[2];
// save the actual state of our wrapped methodExpression
stateStruct[0] = ((StateHolder) methodExpression).saveState(context);
// save the class name of the methodExpression impl
stateStruct[1] = methodExpression.getClass().getName();
result = stateStruct;
}
else
{
result = methodExpression;
}
}
return result;
}
public void restoreState(final FacesContext context, final Object state)
{
if (context == null)
{
throw new NullPointerException();
}
// if we have state
if (null == state)
{
return;
}
if (!(state instanceof MethodExpression))
{
Object[] stateStruct = (Object[]) state;
Object savedState = stateStruct[0];
String className = stateStruct[1].toString();
MethodExpression result = null;
Class toRestoreClass = null;
if (null != className)
{
try
{
toRestoreClass = loadClass(className, this);
}
catch (ClassNotFoundException e)
{
throw new IllegalStateException(e.getMessage());
}
if (null != toRestoreClass)
{
try
{
result = (MethodExpression) toRestoreClass.newInstance();
}
catch (InstantiationException e)
{
throw new IllegalStateException(e.getMessage());
}
catch (IllegalAccessException a)
{
throw new IllegalStateException(a.getMessage());
}
}
if ((null != result) && (null != savedState))
{
// don't need to check transient, since that was
// done on the saving side.
((StateHolder) result).restoreState(context, savedState);
}
methodExpression = result;
}
}
else
{
methodExpression = (MethodExpression) state;
}
}
public MethodExpression getWrapped()
{
return methodExpression;
}
//
// Helper methods for StateHolder
//
private static Class loadClass(final String name, final Object fallbackClass) throws ClassNotFoundException
{
ClassLoader loader = Thread.currentThread().getContextClassLoader();
if (loader == null)
{
loader = fallbackClass.getClass().getClassLoader();
}
return Class.forName(name, true, loader);
}
}