BasicDynaClass.java
/*
* 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 org.apache.commons.beanutils2;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.Objects;
/**
* <p>
* Minimal implementation of the {@code DynaClass} interface. Can be used as a convenience base class for more sophisticated implementations.
* </p>
* <p>
* <strong>IMPLEMENTATION NOTE</strong> - The {@code DynaBean} implementation class supplied to our constructor MUST have a one-argument constructor of its own
* that accepts a {@code DynaClass}. This is used to associate the DynaBean instance with this DynaClass.
* </p>
*/
public class BasicDynaClass implements DynaClass {
private static final long serialVersionUID = 1L;
/**
* The method signature of the constructor we will use to create new DynaBean instances.
*/
private static final Class<?>[] CONSTRUCTOR_TYPES = { DynaClass.class };
/**
* The constructor of the {@code dynaBeanClass} that we will use for creating new instances.
*/
protected transient Constructor<?> constructor;
/**
* The argument values to be passed to the constructor we will use to create new DynaBean instances.
*/
protected Object[] constructorValues = { this };
/**
* The {@code DynaBean} implementation class we will use for creating new instances.
*/
protected Class<?> dynaBeanClass = BasicDynaBean.class;
/**
* The "name" of this DynaBean class.
*/
protected String name = this.getClass().getName();
/**
* The set of dynamic properties that are part of this DynaClass.
*/
protected DynaProperty[] properties = DynaProperty.EMPTY_ARRAY;
/**
* The set of dynamic properties that are part of this DynaClass, keyed by the property name. Individual descriptor instances will be the same instances as
* those in the {@code properties} list.
*/
protected HashMap<String, DynaProperty> propertiesMap = new HashMap<>();
/**
* Constructs a new BasicDynaClass with default parameters.
*/
public BasicDynaClass() {
this(null, null, null);
}
/**
* Constructs a new BasicDynaClass with the specified parameters.
*
* @param name Name of this DynaBean class
* @param dynaBeanClass The implementation class for new instances
*/
public BasicDynaClass(final String name, final Class<?> dynaBeanClass) {
this(name, dynaBeanClass, null);
}
/**
* Constructs a new BasicDynaClass with the specified parameters.
*
* @param name Name of this DynaBean class
* @param dynaBeanClass The implementation class for new instances
* @param properties Property descriptors for the supported properties
*/
public BasicDynaClass(final String name, Class<?> dynaBeanClass, final DynaProperty[] properties) {
if (name != null) {
this.name = name;
}
if (dynaBeanClass == null) {
dynaBeanClass = BasicDynaBean.class;
}
setDynaBeanClass(dynaBeanClass);
if (properties != null) {
setProperties(properties);
}
}
/**
* Gets the Class object we will use to create new instances in the {@code newInstance()} method. This Class <strong>MUST</strong> implement the
* {@code DynaBean} interface.
*
* @return The class of the {@link DynaBean}
*/
public Class<?> getDynaBeanClass() {
return this.dynaBeanClass;
}
/**
* <p>
* Return an array of {@code PropertyDescriptor} for the properties currently defined in this DynaClass. If no properties are defined, a zero-length array
* will be returned.
* </p>
*
* <p>
* <strong>FIXME</strong> - Should we really be implementing {@code getBeanInfo()} instead, which returns property descriptors and a bunch of other stuff?
* </p>
*
* @return the set of properties for this DynaClass
*/
@Override
public DynaProperty[] getDynaProperties() {
return properties.clone();
}
/**
* Gets a property descriptor for the specified property, if it exists; otherwise, return {@code null}.
*
* @param name Name of the dynamic property for which a descriptor is requested
* @return The descriptor for the specified property
* @throws IllegalArgumentException if no property name is specified
*/
@Override
public DynaProperty getDynaProperty(final String name) {
return propertiesMap.get(Objects.requireNonNull(name, "name"));
}
/**
* Gets the name of this DynaClass (analogous to the {@code getName()} method of {@link Class}, which allows the same {@code DynaClass} implementation class
* to support different dynamic classes, with different sets of properties.
*
* @return the name of the DynaClass
*/
@Override
public String getName() {
return this.name;
}
/**
* Instantiate and return a new DynaBean instance, associated with this DynaClass.
*
* @return A new {@code DynaBean} instance
* @throws IllegalAccessException if the Class or the appropriate constructor is not accessible
* @throws InstantiationException if this Class represents an abstract class, an array class, a primitive type, or void; or if instantiation fails for some
* other reason
*/
@Override
public DynaBean newInstance() throws IllegalAccessException, InstantiationException {
try {
// Refind the constructor after a deserialization (if needed)
if (constructor == null) {
setDynaBeanClass(this.dynaBeanClass);
}
// Invoke the constructor to create a new bean instance
return (DynaBean) constructor.newInstance(constructorValues);
} catch (final InvocationTargetException e) {
throw new InstantiationException(e.getTargetException().getMessage());
}
}
/**
* Sets the Class object we will use to create new instances in the {@code newInstance()} method. This Class <strong>MUST</strong> implement the
* {@code DynaBean} interface.
*
* @param dynaBeanClass The new Class object
* @throws IllegalArgumentException if the specified Class does not implement the {@code DynaBean} interface
*/
protected void setDynaBeanClass(final Class<?> dynaBeanClass) {
// Validate the argument type specified
if (dynaBeanClass.isInterface()) {
throw new IllegalArgumentException("Class " + dynaBeanClass.getName() + " is an interface, not a class");
}
if (!DynaBean.class.isAssignableFrom(dynaBeanClass)) {
throw new IllegalArgumentException("Class " + dynaBeanClass.getName() + " does not implement DynaBean");
}
// Identify the Constructor we will use in newInstance()
try {
this.constructor = dynaBeanClass.getConstructor(CONSTRUCTOR_TYPES);
} catch (final NoSuchMethodException e) {
throw new IllegalArgumentException("Class " + dynaBeanClass.getName() + " does not have an appropriate constructor");
}
this.dynaBeanClass = dynaBeanClass;
}
/**
* Sets the list of dynamic properties supported by this DynaClass.
*
* @param properties List of dynamic properties to be supported
*/
protected void setProperties(final DynaProperty[] properties) {
this.properties = Objects.requireNonNull(properties, "properties");
propertiesMap.clear();
for (final DynaProperty property : properties) {
propertiesMap.put(property.getName(), property);
}
}
}