com.vaadin.data.util.NestedMethodProperty Maven / Gradle / Ivy
/*
* Copyright 2000-2014 Vaadin Ltd.
*
* 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 com.vaadin.data.util;
import static com.vaadin.util.ReflectTools.convertPrimitiveType;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import com.vaadin.data.Property;
import com.vaadin.data.util.MethodProperty.MethodException;
import com.vaadin.shared.util.SharedUtil;
/**
* Nested accessor based property for a bean.
*
* The property is specified in the dotted notation, e.g. "address.street", and
* can contain multiple levels of nesting.
*
* When accessing the property value, all intermediate getters must exist and
* should return non-null values when the property value is accessed. If an
* intermediate getter returns null, a null value will be returned.
*
* @see MethodProperty
*
* @since 6.6
*/
public class NestedMethodProperty extends AbstractProperty {
// needed for de-serialization
private String propertyName;
// chain of getter methods
private transient List getMethods;
/**
* The setter method.
*/
private transient Method setMethod;
/**
* Bean instance used as a starting point for accessing the property value.
*/
private Object instance;
private Class type;
/* Special serialization to handle method references */
private void writeObject(java.io.ObjectOutputStream out) throws IOException {
out.defaultWriteObject();
// getMethods and setMethod are reconstructed on read based on
// propertyName
}
/* Special serialization to handle method references */
private void readObject(java.io.ObjectInputStream in) throws IOException,
ClassNotFoundException {
in.defaultReadObject();
initialize(instance.getClass(), propertyName);
}
/**
* Constructs a nested method property for a given object instance. The
* property name is a dot separated string pointing to a nested property,
* e.g. "manager.address.street".
*
* Calling getValue will return null if any intermediate getter returns null
*
* @param instance
* top-level bean to which the property applies
* @param propertyName
* dot separated nested property name
* @throws IllegalArgumentException
* if the property name is invalid
*/
public NestedMethodProperty(Object instance, String propertyName) {
this.instance = instance;
initialize(instance.getClass(), propertyName);
}
/**
* For internal use to deduce property type etc. without a bean instance.
* Calling {@link #setValue(Object)} or {@link #getValue()} on properties
* constructed this way is not supported.
*
* @param instanceClass
* class of the top-level bean
* @param propertyName
*/
NestedMethodProperty(Class instanceClass, String propertyName) {
instance = null;
initialize(instanceClass, propertyName);
}
/**
* Initializes most of the internal fields based on the top-level bean
* instance and property name (dot-separated string).
*
* @param beanClass
* class of the top-level bean to which the property applies
* @param propertyName
* dot separated nested property name
* @throws IllegalArgumentException
* if the property name is invalid
*/
private void initialize(Class beanClass, String propertyName)
throws IllegalArgumentException {
List getMethods = new ArrayList();
String lastSimplePropertyName = propertyName;
Class lastClass = beanClass;
// first top-level property, then go deeper in a loop
Class propertyClass = beanClass;
String[] simplePropertyNames = propertyName.split("\\.");
if (propertyName.endsWith(".") || 0 == simplePropertyNames.length) {
throw new IllegalArgumentException("Invalid property name '"
+ propertyName + "'");
}
for (int i = 0; i < simplePropertyNames.length; i++) {
String simplePropertyName = simplePropertyNames[i].trim();
if (simplePropertyName.length() > 0) {
lastSimplePropertyName = simplePropertyName;
lastClass = propertyClass;
try {
Method getter = MethodProperty.initGetterMethod(
simplePropertyName, propertyClass);
propertyClass = getter.getReturnType();
getMethods.add(getter);
} catch (final java.lang.NoSuchMethodException e) {
throw new IllegalArgumentException("Bean property '"
+ simplePropertyName + "' not found", e);
}
} else {
throw new IllegalArgumentException(
"Empty or invalid bean property identifier in '"
+ propertyName + "'");
}
}
// In case the get method is found, resolve the type
Method lastGetMethod = getMethods.get(getMethods.size() - 1);
Class type = lastGetMethod.getReturnType();
// Finds the set method
Method setMethod = null;
try {
// Assure that the first letter is upper cased (it is a common
// mistake to write firstName, not FirstName).
lastSimplePropertyName = SharedUtil
.capitalize(lastSimplePropertyName);
setMethod = lastClass.getMethod("set" + lastSimplePropertyName,
new Class[] { type });
} catch (final NoSuchMethodException skipped) {
}
this.type = (Class) convertPrimitiveType(type);
this.propertyName = propertyName;
this.getMethods = getMethods;
this.setMethod = setMethod;
}
@Override
public Class getType() {
return type;
}
@Override
public boolean isReadOnly() {
return super.isReadOnly() || (null == setMethod);
}
/**
* Gets the value stored in the Property. The value is resolved by calling
* the specified getter method with the argument specified at instantiation.
*
* @return the value of the Property
*/
@Override
public T getValue() {
try {
Object object = instance;
for (Method m : getMethods) {
object = m.invoke(object);
if (object == null) {
return null;
}
}
return (T) object;
} catch (final Throwable e) {
throw new MethodException(this, e);
}
}
/**
* Sets the value of the property. The new value must be assignable to the
* type of this property.
*
* @param newValue
* the New value of the property.
* @throws Property.ReadOnlyException if the object is in
* read-only mode.
* @see #invokeSetMethod(Object)
*/
@Override
public void setValue(T newValue) throws ReadOnlyException {
// Checks the mode
if (isReadOnly()) {
throw new Property.ReadOnlyException();
}
invokeSetMethod(newValue);
fireValueChange();
}
/**
* Internal method to actually call the setter method of the wrapped
* property.
*
* @param value
*/
protected void invokeSetMethod(T value) {
try {
Object object = instance;
for (int i = 0; i < getMethods.size() - 1; i++) {
object = getMethods.get(i).invoke(object);
}
setMethod.invoke(object, new Object[] { value });
} catch (final InvocationTargetException e) {
throw new MethodException(this, e.getTargetException());
} catch (final Exception e) {
throw new MethodException(this, e);
}
}
/**
* Returns an unmodifiable list of getter methods to call in sequence to get
* the property value.
*
* This API may change in future versions.
*
* @return unmodifiable list of getter methods corresponding to each segment
* of the property name
*/
protected List getGetMethods() {
return Collections.unmodifiableList(getMethods);
}
}