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/*
* 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 javax.el;
import java.beans.FeatureDescriptor;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Objects;
public class ListELResolver extends ELResolver {
private final boolean readOnly;
private static final Class<?> UNMODIFIABLE =
Collections.unmodifiableList(new ArrayList<>()).getClass();
public ListELResolver() {
this.readOnly = false;
}
public ListELResolver(boolean readOnly) {
this.readOnly = readOnly;
}
@Override
public Class<?> getType(ELContext context, Object base, Object property) {
Objects.requireNonNull(context);
if (base instanceof List<?>) {
context.setPropertyResolved(base, property);
List<?> list = (List<?>) base;
int idx = coerce(property);
if (idx < 0 || idx >= list.size()) {
throw new PropertyNotFoundException(
new ArrayIndexOutOfBoundsException(idx).getMessage());
}
return Object.class;
}
return null;
}
@Override
public Object getValue(ELContext context, Object base, Object property) {
Objects.requireNonNull(context);
if (base instanceof List<?>) {
context.setPropertyResolved(base, property);
List<?> list = (List<?>) base;
int idx = coerce(property);
if (idx < 0 || idx >= list.size()) {
return null;
}
return list.get(idx);
}
return null;
}
@Override
public void setValue(ELContext context, Object base, Object property,
Object value) {
Objects.requireNonNull(context);
if (base instanceof List<?>) {
context.setPropertyResolved(base, property);
@SuppressWarnings("unchecked") // Must be OK to cast to Object
List<Object> list = (List<Object>) base;
if (this.readOnly) {
throw new PropertyNotWritableException(Util.message(context,
"resolverNotWriteable", base.getClass().getName()));
}
int idx = coerce(property);
try {
list.set(idx, value);
} catch (UnsupportedOperationException e) {
throw new PropertyNotWritableException(e);
} catch (IndexOutOfBoundsException e) {
throw new PropertyNotFoundException(e);
}
}
}
@Override
public boolean isReadOnly(ELContext context, Object base, Object property) {
Objects.requireNonNull(context);
if (base instanceof List<?>) {
context.setPropertyResolved(base, property);
List<?> list = (List<?>) base;
try {
int idx = coerce(property);
if (idx < 0 || idx >= list.size()) {
throw new PropertyNotFoundException(
new ArrayIndexOutOfBoundsException(idx)
.getMessage());
}
} catch (IllegalArgumentException e) {
// ignore
}
return this.readOnly || UNMODIFIABLE.equals(list.getClass());
}
return this.readOnly;
}
@Override
public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base) {
return null;
}
@Override
public Class<?> getCommonPropertyType(ELContext context, Object base) {
if (base instanceof List<?>) { // implies base != null
return Integer.class;
}
return null;
}
private static final int coerce(Object property) {
if (property instanceof Number) {
return ((Number) property).intValue();
}
if (property instanceof Character) {
return ((Character) property).charValue();
}
if (property instanceof Boolean) {
return (((Boolean) property).booleanValue() ? 1 : 0);
}
if (property instanceof String) {
return Integer.parseInt((String) property);
}
throw new IllegalArgumentException(property != null ?
property.toString() : "null");
}
}
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