Java tutorial
/* * Copyright 2002-2011 the original author or authors. * * 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 org.jdal.ui.bind; import java.beans.PropertyChangeEvent; import java.lang.reflect.Field; import java.util.HashMap; import java.util.Map; import org.springframework.beans.AbstractPropertyAccessor; import org.springframework.beans.BeanWrapper; import org.springframework.beans.BeansException; import org.springframework.beans.ConversionNotSupportedException; import org.springframework.beans.InvalidPropertyException; import org.springframework.beans.NotReadablePropertyException; import org.springframework.beans.NotWritablePropertyException; import org.springframework.beans.PropertyAccessor; import org.springframework.beans.SimpleTypeConverter; import org.springframework.beans.TypeConverter; import org.springframework.beans.TypeMismatchException; import org.springframework.core.MethodParameter; import org.springframework.core.convert.ConversionException; import org.springframework.core.convert.ConverterNotFoundException; import org.springframework.core.convert.TypeDescriptor; import org.springframework.util.Assert; import org.springframework.util.ReflectionUtils; /** * {@link PropertyAccessor} implementation that directly accesses instance fields. * Allows for direct binding to fields instead of going through JavaBean setters. * * <p>This implementation just supports fields in the actual target object. * It is not able to traverse nested fields. * * <p>A DirectFieldAccessor's default for the "extractOldValueForEditor" setting * is "true", since a field can always be read without side effects. * * Note: This class was copied from spring framework for use in AbstractView until * SPR-8389 become fixed and released.<strong> Don't use it, it will be deleted soon</strong> * * * @author Juergen Hoeller * @since 2.0 * @see #setExtractOldValueForEditor * @see BeanWrapper * @see org.springframework.validation.DirectFieldBindingResult * @see org.springframework.validation.DataBinder#initDirectFieldAccess() */ public class DirectFieldAccessor extends AbstractPropertyAccessor { private final Object target; private final Map<String, Field> fieldMap = new HashMap<String, Field>(); private final TypeConverter typeConverterDelegate; /** * Create a new DirectFieldAccessor for the given target object. * @param target the target object to access */ public DirectFieldAccessor(final Object target) { Assert.notNull(target, "Target object must not be null"); this.target = target; ReflectionUtils.doWithFields(this.target.getClass(), new ReflectionUtils.FieldCallback() { public void doWith(Field field) { // jlm - FIX SPR-8398: avoid to overwrite shadowed fileds if (!fieldMap.containsKey(field.getName())) { fieldMap.put(field.getName(), field); } } }); this.typeConverterDelegate = new SimpleTypeConverter(); registerDefaultEditors(); setExtractOldValueForEditor(true); } public boolean isReadableProperty(String propertyName) throws BeansException { return this.fieldMap.containsKey(propertyName); } public boolean isWritableProperty(String propertyName) throws BeansException { return this.fieldMap.containsKey(propertyName); } @Override public Class<?> getPropertyType(String propertyName) throws BeansException { Field field = this.fieldMap.get(propertyName); if (field != null) { return field.getType(); } return null; } public TypeDescriptor getPropertyTypeDescriptor(String propertyName) throws BeansException { Field field = this.fieldMap.get(propertyName); if (field != null) { return new TypeDescriptor(field); } return null; } @Override public Object getPropertyValue(String propertyName) throws BeansException { Field field = this.fieldMap.get(propertyName); if (field == null) { throw new NotReadablePropertyException(this.target.getClass(), propertyName, "Field '" + propertyName + "' does not exist"); } try { ReflectionUtils.makeAccessible(field); return field.get(this.target); } catch (IllegalAccessException ex) { throw new InvalidPropertyException(this.target.getClass(), propertyName, "Field is not accessible", ex); } } @Override public void setPropertyValue(String propertyName, Object newValue) throws BeansException { Field field = this.fieldMap.get(propertyName); if (field == null) { throw new NotWritablePropertyException(this.target.getClass(), propertyName, "Field '" + propertyName + "' does not exist"); } Object oldValue = null; try { ReflectionUtils.makeAccessible(field); oldValue = field.get(this.target); // jlm - Adapt to simpleTypeConverter Object convertedValue = this.typeConverterDelegate.convertIfNecessary(newValue, field.getType()); field.set(this.target, convertedValue); } catch (ConverterNotFoundException ex) { PropertyChangeEvent pce = new PropertyChangeEvent(this.target, propertyName, oldValue, newValue); throw new ConversionNotSupportedException(pce, field.getType(), ex); } catch (ConversionException ex) { PropertyChangeEvent pce = new PropertyChangeEvent(this.target, propertyName, oldValue, newValue); throw new TypeMismatchException(pce, field.getType(), ex); } catch (IllegalStateException ex) { PropertyChangeEvent pce = new PropertyChangeEvent(this.target, propertyName, oldValue, newValue); throw new ConversionNotSupportedException(pce, field.getType(), ex); } catch (IllegalArgumentException ex) { PropertyChangeEvent pce = new PropertyChangeEvent(this.target, propertyName, oldValue, newValue); throw new TypeMismatchException(pce, field.getType(), ex); } catch (IllegalAccessException ex) { throw new InvalidPropertyException(this.target.getClass(), propertyName, "Field is not accessible", ex); } } public <T> T convertIfNecessary(Object value, Class<T> requiredType, MethodParameter methodParam) throws TypeMismatchException { try { return this.typeConverterDelegate.convertIfNecessary(value, requiredType, methodParam); } catch (IllegalArgumentException ex) { throw new TypeMismatchException(value, requiredType, ex); } catch (IllegalStateException ex) { throw new ConversionNotSupportedException(value, requiredType, ex); } } }