impl/src/main/java/org/apache/myfaces/el/resolver/MethodHandleBeanELResolver.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 *
 * 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.apache.myfaces.el.resolver;

import java.util.Map;
import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;

import javax.el.BeanELResolver;
import javax.el.ELContext;
import javax.el.ELException;
import javax.el.PropertyNotWritableException;
import org.apache.myfaces.util.lang.MethodHandleUtils;

public class MethodHandleBeanELResolver extends BeanELResolver
{
    private final ConcurrentHashMap<String, Map<String, MethodHandleUtils.LambdaPropertyDescriptor>> cache;

    public MethodHandleBeanELResolver()
    {
        if (MethodHandleUtils.isSupported())
        {
            cache = new ConcurrentHashMap<>(1000);
        }
        else
        {
            cache = null;
        }
    }

    @Override
    public Class<?> getType(ELContext context, Object base, Object property)
    {
        if (!MethodHandleUtils.isSupported())
        {
            return super.getType(context, base, property);
        }

        Objects.requireNonNull(context);
        if (base == null || property == null)
        {
            return null;
        }

        context.setPropertyResolved(base, property);

        return getPropertyDescriptor(base, property).getType();
    }

    @SuppressWarnings("unchecked")
    @Override
    public Object getValue(ELContext context, Object base, Object property)
    {
        if (!MethodHandleUtils.isSupported())
        {
            return super.getValue(context, base, property);
        }
        
        Objects.requireNonNull(context);
        if (base == null || property == null)
        {
            return null;
        }

        context.setPropertyResolved(base, property);

        try
        {
            return getPropertyDescriptor(base, property).getGetter().apply(base);
        }
        catch (Exception e)
        {
            throw new ELException(e);
        }
    }

    @SuppressWarnings("unchecked")
    @Override
    public void setValue(ELContext context, Object base, Object property, Object value)
    {
        if (!MethodHandleUtils.isSupported())
        {
            super.setValue(context, base, property, value);
            return;
        }
        
        Objects.requireNonNull(context);
        if (base == null || property == null)
        {
            return;
        }

        context.setPropertyResolved(base, property);

        MethodHandleUtils.LambdaPropertyDescriptor propertyDescriptor = getPropertyDescriptor(base, property);
        if (propertyDescriptor.getSetter() == null)
        {
            throw new PropertyNotWritableException("Property \"" + (String) property
                    + "\" in \"" + base.getClass().getName() + "\" is not writable!");
        }

        try
        {
            propertyDescriptor.getSetter().accept(base, value);
        }
        catch (Exception e)
        {
            throw new ELException(e);
        }
    }

    @Override
    public boolean isReadOnly(ELContext context, Object base, Object property)
    {
        if (!MethodHandleUtils.isSupported())
        {
            return super.isReadOnly(context, base, property);
        }

        Objects.requireNonNull(context);
        if (base == null || property == null)
        {
            return false;
        }

        context.setPropertyResolved(base, property);

        return getPropertyDescriptor(base, property).getSetter() == null;
    }

    @Override
    public Class<?> getCommonPropertyType(ELContext context, Object base)
    {
        if (!MethodHandleUtils.isSupported())
        {
            return super.getCommonPropertyType(context, base);
        }
        
        if (base != null)
        {
            return Object.class;
        }

        return null;
    }

    protected MethodHandleUtils.LambdaPropertyDescriptor getPropertyDescriptor(Object base, Object property)
    {
        Map<String, MethodHandleUtils.LambdaPropertyDescriptor> beanCache = cache.computeIfAbsent(
                base.getClass().getName(), k -> MethodHandleUtils.getLambdaPropertyDescriptors(base.getClass()));
        return beanCache.get((String) property);
    }

}