JasperELResolver.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.jasper.el;
import java.beans.FeatureDescriptor;
import java.lang.reflect.Method;
import java.util.Iterator;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicInteger;
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;
import org.apache.jasper.runtime.ExceptionUtils;
import org.apache.jasper.runtime.JspRuntimeLibrary;
/**
* 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 AtomicInteger resolversSize = new AtomicInteger(0);
private volatile ELResolver[] resolvers;
private final int appResolversSize;
public JasperELResolver(List<ELResolver> appResolvers,
ELResolver streamResolver) {
appResolversSize = appResolvers.size();
resolvers = new ELResolver[appResolversSize + STANDARD_RESOLVERS_COUNT];
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());
if (JspRuntimeLibrary.GRAAL) {
add(new GraalBeanELResolver());
}
add(new BeanELResolver());
add(new ScopedAttributeELResolver());
}
@Override
public synchronized void add(ELResolver elResolver) {
super.add(elResolver);
int size = resolversSize.get();
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;
}
resolversSize.incrementAndGet();
}
@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;
if (JspRuntimeLibrary.GRAAL) {
start++;
}
} else {
// skip implicit resolver only
start = 1;
}
int size = resolversSize.get();
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
int size = resolversSize.get();
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 org.apache.el.lang.ELSupport#coerceToString(ELContext,Object)
*/
private static 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();
}
}
/**
* Extend ELResolver for Graal to avoid bean info use if possible,
* as BeanELResolver needs manual reflection configuration.
*/
public static class GraalBeanELResolver extends ELResolver {
@Override
public Object getValue(ELContext context, Object base,
Object property) {
Objects.requireNonNull(context);
if (base == null || property == null) {
return null;
}
Object value = null;
Method method = getReadMethod(base.getClass(), property.toString());
if (method != null) {
context.setPropertyResolved(base, property);
try {
method.setAccessible(true);
value = method.invoke(base, (Object[]) null);
} catch (Exception ex) {
Throwable thr = ExceptionUtils.unwrapInvocationTargetException(ex);
ExceptionUtils.handleThrowable(thr);
}
}
return value;
}
@Override
public void setValue(ELContext context, Object base, Object property,
Object value) {
Objects.requireNonNull(context);
if (base == null || property == null) {
return;
}
Method method = getWriteMethod(base.getClass(), property.toString(), value.getClass());
if (method != null) {
context.setPropertyResolved(base, property);
try {
method.invoke(base, value);
} catch (Exception ex) {
Throwable thr = ExceptionUtils.unwrapInvocationTargetException(ex);
ExceptionUtils.handleThrowable(thr);
}
}
}
@Override
public boolean isReadOnly(ELContext context, Object base,
Object property) {
Objects.requireNonNull(context);
if (base == null || property == null) {
return false;
}
Class<?> beanClass = base.getClass();
String prop = property.toString();
Method readMethod = getReadMethod(beanClass, prop);
return readMethod == null || !(getWriteMethod(beanClass, prop, readMethod.getReturnType()) != null);
}
private static Method getReadMethod(Class<?> beanClass, String prop) {
Method methods[] = beanClass.getMethods();
String isGetter = "is" + capitalize(prop);
String getter = "get" + capitalize(prop);
for (Method method : methods) {
if (method.getParameterCount() == 0) {
if (isGetter.equals(method.getName()) && method.getReturnType().equals(boolean.class)) {
return method;
} else if (getter.equals(method.getName())) {
return method;
}
}
}
return null;
}
private static Method getWriteMethod(Class<?> beanClass, String prop, Class<?> valueClass) {
String setter = "set" + capitalize(prop);
Method methods[] = beanClass.getMethods();
for (Method method : methods) {
if (method.getParameterCount() == 1 && setter.equals(method.getName())
&& (valueClass == null || valueClass.isAssignableFrom(method.getParameterTypes()[0]))) {
return method;
}
}
return null;
}
private static String capitalize(String name) {
if (name == null || name.length() == 0) {
return name;
}
char chars[] = name.toCharArray();
chars[0] = Character.toUpperCase(chars[0]);
return new String(chars);
}
@Override
public Class<?> getType(ELContext context, Object base,
Object property) {
return null;
}
@Override
public Iterator<FeatureDescriptor> getFeatureDescriptors(
ELContext context, Object base) {
return null;
}
@Override
public Class<?> getCommonPropertyType(ELContext context, Object base) {
if (base != null) {
return Object.class;
}
return null;
}
}
}