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/*
* =========================================================================================
* Copyright © 2013-2015 the kamon project <http://kamon.io/>
*
* Licensed 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 kamon.annotation.el.resolver;
import java.beans.FeatureDescriptor;
import java.lang.reflect.Field;
import java.util.Iterator;
import javax.el.ELContext;
import javax.el.ELException;
import javax.el.ELResolver;
/**
* A custom {@link ELResolver} for mapping properties to public/private fields of the base object.
*/
public class PrivateFieldELResolver extends ELResolver {
@Override
public Object getValue(ELContext context, Object base, Object property) {
if (base == null) {
return null;
}
try {
Field field = getField(base, (String) property);
context.setPropertyResolved(true);
field.setAccessible(true);
return field.get(base);
} catch (NoSuchFieldException exc) {
context.setPropertyResolved(false);
return null;
} catch (Exception exc) {
throw new ELException(exc);
}
}
private Field getField(Object base, String property) throws NoSuchFieldException {
try {
return base.getClass().getDeclaredField(property);
} catch (SecurityException exc) {
throw new ELException(exc);
}
}
@Override
public Class<?> getType(ELContext context, Object base, Object property) {
if (base == null) {
return null;
}
try {
Field field = getField(base, (String) property);
if (field != null) {
context.setPropertyResolved(true);
return field.getType();
} else {
return null;
}
} catch (NoSuchFieldException exc) {
context.setPropertyResolved(false);
return null;
}
}
@Override
public void setValue(ELContext context, Object base, Object property, Object value) {
if (base == null) {
return;
}
try {
context.setPropertyResolved(true);
getField(base, (String) property).set(base, value);
} catch (NoSuchFieldException exc) {
context.setPropertyResolved(false);
} catch (Exception exc) {
throw new ELException(exc);
}
}
@Override
public boolean isReadOnly(ELContext context, Object base, Object property) {
if (base == null) {
return true;
}
try {
Field field = getField(base, (String) property);
if (field != null) {
context.setPropertyResolved(true);
return !field.isAccessible();
}
} catch (NoSuchFieldException exc) {
context.setPropertyResolved(false);
}
return false;
}
@Override
public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base) {
return null;
}
@Override
public Class<?> getCommonPropertyType(ELContext context, Object base) {
return String.class;
}
}
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