org.springframework.beans.PropertyDescriptorUtils Maven / Gradle / Ivy
/*
* Copyright 2002-2024 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
*
* https://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.springframework.beans;
import java.beans.IntrospectionException;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import org.springframework.lang.Nullable;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;
/**
* Common delegate methods for Spring's internal {@link PropertyDescriptor} implementations.
*
* @author Chris Beams
* @author Juergen Hoeller
*/
abstract class PropertyDescriptorUtils {
public static final PropertyDescriptor[] EMPTY_PROPERTY_DESCRIPTOR_ARRAY = {};
/**
* Simple introspection algorithm for basic set/get/is accessor methods,
* building corresponding JavaBeans property descriptors for them.
* This just supports the basic JavaBeans conventions, without indexed
* properties or any customizers, and without other BeanInfo metadata.
* For standard JavaBeans introspection, use the JavaBeans Introspector.
* @param beanClass the target class to introspect
* @return a collection of property descriptors
* @throws IntrospectionException from introspecting the given bean class
* @since 5.3.24
* @see SimpleBeanInfoFactory
* @see java.beans.Introspector#getBeanInfo(Class)
*/
public static Collection determineBasicProperties(Class beanClass)
throws IntrospectionException {
Map pdMap = new TreeMap<>();
for (Method method : beanClass.getMethods()) {
String methodName = method.getName();
boolean setter;
int nameIndex;
if (methodName.startsWith("set") && method.getParameterCount() == 1) {
setter = true;
nameIndex = 3;
}
else if (methodName.startsWith("get") && method.getParameterCount() == 0 && method.getReturnType() != void.class) {
setter = false;
nameIndex = 3;
}
else if (methodName.startsWith("is") && method.getParameterCount() == 0 && method.getReturnType() == boolean.class) {
setter = false;
nameIndex = 2;
}
else {
continue;
}
String propertyName = StringUtils.uncapitalizeAsProperty(methodName.substring(nameIndex));
if (propertyName.isEmpty()) {
continue;
}
BasicPropertyDescriptor pd = pdMap.get(propertyName);
if (pd != null) {
if (setter) {
Method writeMethod = pd.getWriteMethod();
if (writeMethod == null ||
writeMethod.getParameterTypes()[0].isAssignableFrom(method.getParameterTypes()[0])) {
pd.setWriteMethod(method);
}
else {
pd.addWriteMethod(method);
}
}
else {
Method readMethod = pd.getReadMethod();
if (readMethod == null ||
(readMethod.getReturnType() == method.getReturnType() && method.getName().startsWith("is"))) {
pd.setReadMethod(method);
}
}
}
else {
pd = new BasicPropertyDescriptor(propertyName, (!setter ? method : null), (setter ? method : null));
pdMap.put(propertyName, pd);
}
}
return pdMap.values();
}
/**
* See {@link java.beans.FeatureDescriptor}.
*/
public static void copyNonMethodProperties(PropertyDescriptor source, PropertyDescriptor target) {
target.setExpert(source.isExpert());
target.setHidden(source.isHidden());
target.setPreferred(source.isPreferred());
target.setName(source.getName());
target.setShortDescription(source.getShortDescription());
target.setDisplayName(source.getDisplayName());
// Copy all attributes (emulating behavior of private FeatureDescriptor#addTable)
Enumeration keys = source.attributeNames();
while (keys.hasMoreElements()) {
String key = keys.nextElement();
target.setValue(key, source.getValue(key));
}
// See java.beans.PropertyDescriptor#PropertyDescriptor(PropertyDescriptor)
target.setPropertyEditorClass(source.getPropertyEditorClass());
target.setBound(source.isBound());
target.setConstrained(source.isConstrained());
}
/**
* See {@link java.beans.PropertyDescriptor#findPropertyType}.
*/
@Nullable
public static Class findPropertyType(@Nullable Method readMethod, @Nullable Method writeMethod)
throws IntrospectionException {
Class propertyType = null;
if (readMethod != null) {
if (readMethod.getParameterCount() != 0) {
throw new IntrospectionException("Bad read method arg count: " + readMethod);
}
propertyType = readMethod.getReturnType();
if (propertyType == void.class) {
throw new IntrospectionException("Read method returns void: " + readMethod);
}
}
if (writeMethod != null) {
Class[] params = writeMethod.getParameterTypes();
if (params.length != 1) {
throw new IntrospectionException("Bad write method arg count: " + writeMethod);
}
if (propertyType != null) {
if (propertyType.isAssignableFrom(params[0])) {
// Write method's property type potentially more specific
propertyType = params[0];
}
else if (params[0].isAssignableFrom(propertyType)) {
// Proceed with read method's property type
}
else {
throw new IntrospectionException(
"Type mismatch between read and write methods: " + readMethod + " - " + writeMethod);
}
}
else {
propertyType = params[0];
}
}
return propertyType;
}
/**
* See {@link java.beans.IndexedPropertyDescriptor#findIndexedPropertyType}.
*/
@Nullable
public static Class findIndexedPropertyType(String name, @Nullable Class propertyType,
@Nullable Method indexedReadMethod, @Nullable Method indexedWriteMethod) throws IntrospectionException {
Class indexedPropertyType = null;
if (indexedReadMethod != null) {
Class[] params = indexedReadMethod.getParameterTypes();
if (params.length != 1) {
throw new IntrospectionException("Bad indexed read method arg count: " + indexedReadMethod);
}
if (params[0] != int.class) {
throw new IntrospectionException("Non int index to indexed read method: " + indexedReadMethod);
}
indexedPropertyType = indexedReadMethod.getReturnType();
if (indexedPropertyType == void.class) {
throw new IntrospectionException("Indexed read method returns void: " + indexedReadMethod);
}
}
if (indexedWriteMethod != null) {
Class[] params = indexedWriteMethod.getParameterTypes();
if (params.length != 2) {
throw new IntrospectionException("Bad indexed write method arg count: " + indexedWriteMethod);
}
if (params[0] != int.class) {
throw new IntrospectionException("Non int index to indexed write method: " + indexedWriteMethod);
}
if (indexedPropertyType != null) {
if (indexedPropertyType.isAssignableFrom(params[1])) {
// Write method's property type potentially more specific
indexedPropertyType = params[1];
}
else if (params[1].isAssignableFrom(indexedPropertyType)) {
// Proceed with read method's property type
}
else {
throw new IntrospectionException("Type mismatch between indexed read and write methods: " +
indexedReadMethod + " - " + indexedWriteMethod);
}
}
else {
indexedPropertyType = params[1];
}
}
if (propertyType != null && (!propertyType.isArray() ||
propertyType.componentType() != indexedPropertyType)) {
throw new IntrospectionException("Type mismatch between indexed and non-indexed methods: " +
indexedReadMethod + " - " + indexedWriteMethod);
}
return indexedPropertyType;
}
/**
* Compare the given {@code PropertyDescriptors} and return {@code true} if
* they are equivalent, i.e. their read method, write method, property type,
* property editor and flags are equivalent.
* @see java.beans.PropertyDescriptor#equals(Object)
*/
public static boolean equals(PropertyDescriptor pd, PropertyDescriptor otherPd) {
return (ObjectUtils.nullSafeEquals(pd.getReadMethod(), otherPd.getReadMethod()) &&
ObjectUtils.nullSafeEquals(pd.getWriteMethod(), otherPd.getWriteMethod()) &&
ObjectUtils.nullSafeEquals(pd.getPropertyType(), otherPd.getPropertyType()) &&
ObjectUtils.nullSafeEquals(pd.getPropertyEditorClass(), otherPd.getPropertyEditorClass()) &&
pd.isBound() == otherPd.isBound() && pd.isConstrained() == otherPd.isConstrained());
}
/**
* PropertyDescriptor for {@link #determineBasicProperties(Class)},
* not performing any early type determination for
* {@link #setReadMethod}/{@link #setWriteMethod}.
* @since 5.3.24
*/
private static class BasicPropertyDescriptor extends PropertyDescriptor {
@Nullable
private Method readMethod;
@Nullable
private Method writeMethod;
private final List alternativeWriteMethods = new ArrayList<>();
public BasicPropertyDescriptor(String propertyName, @Nullable Method readMethod, @Nullable Method writeMethod)
throws IntrospectionException {
super(propertyName, readMethod, writeMethod);
}
@Override
public void setReadMethod(@Nullable Method readMethod) {
this.readMethod = readMethod;
}
@Override
@Nullable
public Method getReadMethod() {
return this.readMethod;
}
@Override
public void setWriteMethod(@Nullable Method writeMethod) {
this.writeMethod = writeMethod;
}
public void addWriteMethod(Method writeMethod) {
if (this.writeMethod != null) {
this.alternativeWriteMethods.add(this.writeMethod);
this.writeMethod = null;
}
this.alternativeWriteMethods.add(writeMethod);
}
@Override
@Nullable
public Method getWriteMethod() {
if (this.writeMethod == null && !this.alternativeWriteMethods.isEmpty()) {
if (this.readMethod == null) {
return this.alternativeWriteMethods.get(0);
}
else {
for (Method method : this.alternativeWriteMethods) {
if (this.readMethod.getReturnType().isAssignableFrom(method.getParameterTypes()[0])) {
this.writeMethod = method;
break;
}
}
}
}
return this.writeMethod;
}
}
}