/*

* 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.jasper.el;

import java.util.List;

import javax.el.ArrayELResolver;

import javax.el.BeanELResolver;

import javax.el.CompositeELResolver;

import javax.el.ELContext;

import javax.el.ELException;

import javax.el.ELResolver;

import javax.el.ListELResolver;

import javax.el.MapELResolver;

import javax.el.PropertyNotFoundException;

import javax.el.ResourceBundleELResolver;

import javax.el.StaticFieldELResolver;

import javax.servlet.jsp.el.ImplicitObjectELResolver;

import javax.servlet.jsp.el.ScopedAttributeELResolver;

/**

* Jasper-specific CompositeELResolver that optimizes certain functions to avoid

* unnecessary resolver calls.

*/

public class JasperELResolver extends CompositeELResolver {

private static final int STANDARD_RESOLVERS_COUNT = 9;

private int size;

private ELResolver[] resolvers;

private final int appResolversSize;

public JasperELResolver(List<ELResolver> appResolvers,

ELResolver streamResolver) {

appResolversSize = appResolvers.size();

resolvers = new ELResolver[appResolversSize + STANDARD_RESOLVERS_COUNT];

size = 0;

add(new ImplicitObjectELResolver());

for (ELResolver appResolver : appResolvers) {

add(appResolver);

}

add(streamResolver);

add(new StaticFieldELResolver());

add(new MapELResolver());

add(new ResourceBundleELResolver());

add(new ListELResolver());

add(new ArrayELResolver());

add(new BeanELResolver());

add(new ScopedAttributeELResolver());

}

@Override

public synchronized void add(ELResolver elResolver) {

super.add(elResolver);

if (resolvers.length > size) {

resolvers[size] = elResolver;

} else {

ELResolver[] nr = new ELResolver[size + 1];

System.arraycopy(resolvers, 0, nr, 0, size);

nr[size] = elResolver;

resolvers = nr;

}

size ++;

}

@Override

public Object getValue(ELContext context, Object base, Object property)

throws NullPointerException, PropertyNotFoundException, ELException {

context.setPropertyResolved(false);

int start;

Object result = null;

if (base == null) {

// call implicit and app resolvers

int index = 1 /* implicit */ + appResolversSize;

for (int i = 0; i < index; i++) {

result = resolvers[i].getValue(context, base, property);

if (context.isPropertyResolved()) {

return result;

}

}

// skip stream, static and collection-based resolvers (map,

// resource, list, array) and bean

start = index + 7;

} else {

// skip implicit resolver only

start = 1;

}

for (int i = start; i < size; i++) {

result = resolvers[i].getValue(context, base, property);

if (context.isPropertyResolved()) {

return result;

}

}

return null;

}

@Override

public Object invoke(ELContext context, Object base, Object method,

Class<?>[] paramTypes, Object[] params) {

String targetMethod = coerceToString(method);

if (targetMethod.length() == 0) {

throw new ELException(new NoSuchMethodException());

}

context.setPropertyResolved(false);

Object result = null;

// skip implicit and call app resolvers, stream resolver and static

// resolver

int index = 1 /* implicit */ + appResolversSize +

2 /* stream + static */;

for (int i = 1; i < index; i++) {

result = resolvers[i].invoke(

context, base, targetMethod, paramTypes, params);

if (context.isPropertyResolved()) {

return result;

}

}

// skip collection (map, resource, list, and array) resolvers

index += 4;

// call bean and the rest of resolvers

for (int i = index; i < size; i++) {

result = resolvers[i].invoke(

context, base, targetMethod, paramTypes, params);

if (context.isPropertyResolved()) {

return result;

}

}

return null;

}

/**

* Copied from {@link org.apache.el.lang.ELSupport#coerceToString(Object)}.

*/

private static final String coerceToString(final Object obj) {

if (obj == null) {

return "";

} else if (obj instanceof String) {

return (String) obj;

} else if (obj instanceof Enum<?>) {

return ((Enum<?>) obj).name();

} else {

return obj.toString();

}

}

}