/*
 * 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 jakarta.el;

import java.beans.FeatureDescriptor;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Iterator;
import java.util.Objects;

Since:EL 3.0
/** * @since EL 3.0 */
public class StaticFieldELResolver extends ELResolver { @Override public Object getValue(ELContext context, Object base, Object property) { Objects.requireNonNull(context); if (base instanceof ELClass && property instanceof String) { context.setPropertyResolved(base, property); Class<?> clazz = ((ELClass) base).getKlass(); String name = (String) property; Exception exception = null; try { Field field = clazz.getField(name); int modifiers = field.getModifiers(); JreCompat jreCompat = JreCompat.getInstance(); if (Modifier.isStatic(modifiers) && Modifier.isPublic(modifiers) && jreCompat.canAccess(null, field)) { return field.get(null); } } catch (IllegalArgumentException | IllegalAccessException | NoSuchFieldException | SecurityException e) { exception = e; } String msg = Util.message(context, "staticFieldELResolver.notFound", name, clazz.getName()); if (exception == null) { throw new PropertyNotFoundException(msg); } else { throw new PropertyNotFoundException(msg, exception); } } return null; } @Override public void setValue(ELContext context, Object base, Object property, Object value) { Objects.requireNonNull(context); if (base instanceof ELClass && property instanceof String) { Class<?> clazz = ((ELClass) base).getKlass(); String name = (String) property; throw new PropertyNotWritableException(Util.message(context, "staticFieldELResolver.notWriteable", name, clazz.getName())); } } @Override public Object invoke(ELContext context, Object base, Object method, Class<?>[] paramTypes, Object[] params) { Objects.requireNonNull(context); if (base instanceof ELClass && method instanceof String) { context.setPropertyResolved(base, method); Class<?> clazz = ((ELClass) base).getKlass(); String methodName = (String) method; if ("<init>".equals(methodName)) { Constructor<?> match = Util.findConstructor(clazz, paramTypes, params); Object[] parameters = Util.buildParameters( match.getParameterTypes(), match.isVarArgs(), params); Object result = null; try { result = match.newInstance(parameters); } catch (InvocationTargetException e) { Throwable cause = e.getCause(); Util.handleThrowable(cause); throw new ELException(cause); } catch (ReflectiveOperationException e) { throw new ELException(e); } return result; } else { // Static method so base should be null Method match = Util.findMethod(clazz, null, methodName, paramTypes, params); // Note: On Java 9 and above, the isStatic check becomes // unnecessary because the canAccess() call in Util.findMethod() // effectively performs the same check if (match == null || !Modifier.isStatic(match.getModifiers())) { throw new MethodNotFoundException(Util.message(context, "staticFieldELResolver.methodNotFound", methodName, clazz.getName())); } Object[] parameters = Util.buildParameters( match.getParameterTypes(), match.isVarArgs(), params); Object result = null; try { result = match.invoke(null, parameters); } catch (IllegalArgumentException | IllegalAccessException e) { throw new ELException(e); } catch (InvocationTargetException e) { Throwable cause = e.getCause(); Util.handleThrowable(cause); throw new ELException(cause); } return result; } } return null; } @Override public Class<?> getType(ELContext context, Object base, Object property) { Objects.requireNonNull(context); if (base instanceof ELClass && property instanceof String) { context.setPropertyResolved(base, property); Class<?> clazz = ((ELClass) base).getKlass(); String name = (String) property; Exception exception = null; try { Field field = clazz.getField(name); int modifiers = field.getModifiers(); JreCompat jreCompat = JreCompat.getInstance(); if (Modifier.isStatic(modifiers) && Modifier.isPublic(modifiers) && jreCompat.canAccess(null, field)) { return field.getType(); } } catch (IllegalArgumentException | NoSuchFieldException | SecurityException e) { exception = e; } String msg = Util.message(context, "staticFieldELResolver.notFound", name, clazz.getName()); if (exception == null) { throw new PropertyNotFoundException(msg); } else { throw new PropertyNotFoundException(msg, exception); } } return null; } @Override public boolean isReadOnly(ELContext context, Object base, Object property) { Objects.requireNonNull(context); if (base instanceof ELClass && property instanceof String) { context.setPropertyResolved(base, property); } return true; }
Always returns null.
/** * Always returns <code>null</code>. */
@Override public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base) { return null; }
Always returns String.class.
/** * Always returns <code>String.class</code>. */
@Override public Class<?> getCommonPropertyType(ELContext context, Object base) { return String.class; } }