    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017
    018package org.apache.commons.beanutils2;
    019
    020import java.lang.reflect.Constructor;
    021import java.lang.reflect.InvocationTargetException;
    022import java.util.HashMap;
    023import java.util.Objects;
    024
    025/**
    026 * <p>
    027 * Minimal implementation of the {@code DynaClass} interface. Can be used as a convenience base class for more sophisticated implementations.
    028 * </p>
    029 * <p>
    030 * <strong>IMPLEMENTATION NOTE</strong> - The {@code DynaBean} implementation class supplied to our constructor MUST have a one-argument constructor of its own
    031 * that accepts a {@code DynaClass}. This is used to associate the DynaBean instance with this DynaClass.
    032 * </p>
    033 */
    034public class BasicDynaClass implements DynaClass {
    035
    036    private static final long serialVersionUID = 1L;
    037
    038    /**
    039     * The method signature of the constructor we will use to create new DynaBean instances.
    040     */
    041    private static final Class<?>[] CONSTRUCTOR_TYPES = { DynaClass.class };
    042
    043    /**
    044     * The constructor of the {@code dynaBeanClass} that we will use for creating new instances.
    045     */
    046    protected transient Constructor<?> constructor;
    047
    048    /**
    049     * The argument values to be passed to the constructor we will use to create new DynaBean instances.
    050     */
    051    protected Object[] constructorValues = { this };
    052
    053    /**
    054     * The {@code DynaBean} implementation class we will use for creating new instances.
    055     */
    056    protected Class<?> dynaBeanClass = BasicDynaBean.class;
    057
    058    /**
    059     * The "name" of this DynaBean class.
    060     */
    061    protected String name = this.getClass().getName();
    062
    063    /**
    064     * The set of dynamic properties that are part of this DynaClass.
    065     */
    066    protected DynaProperty[] properties = DynaProperty.EMPTY_ARRAY;
    067
    068    /**
    069     * 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
    070     * those in the {@code properties} list.
    071     */
    072    protected HashMap<String, DynaProperty> propertiesMap = new HashMap<>();
    073
    074    /**
    075     * Constructs a new BasicDynaClass with default parameters.
    076     */
    077    public BasicDynaClass() {
    078        this(null, null, null);
    079    }
    080
    081    /**
    082     * Constructs a new BasicDynaClass with the specified parameters.
    083     *
    084     * @param name          Name of this DynaBean class
    085     * @param dynaBeanClass The implementation class for new instances
    086     */
    087    public BasicDynaClass(final String name, final Class<?> dynaBeanClass) {
    088        this(name, dynaBeanClass, null);
    089    }
    090
    091    /**
    092     * Constructs a new BasicDynaClass with the specified parameters.
    093     *
    094     * @param name          Name of this DynaBean class
    095     * @param dynaBeanClass The implementation class for new instances
    096     * @param properties    Property descriptors for the supported properties
    097     */
    098    public BasicDynaClass(final String name, Class<?> dynaBeanClass, final DynaProperty[] properties) {
    099        if (name != null) {
    100            this.name = name;
    101        }
    102        if (dynaBeanClass == null) {
    103            dynaBeanClass = BasicDynaBean.class;
    104        }
    105        setDynaBeanClass(dynaBeanClass);
    106        if (properties != null) {
    107            setProperties(properties);
    108        }
    109    }
    110
    111    /**
    112     * Gets the Class object we will use to create new instances in the {@code newInstance()} method. This Class <strong>MUST</strong> implement the
    113     * {@code DynaBean} interface.
    114     *
    115     * @return The class of the {@link DynaBean}
    116     */
    117    public Class<?> getDynaBeanClass() {
    118        return this.dynaBeanClass;
    119    }
    120
    121    /**
    122     * <p>
    123     * Return an array of {@code PropertyDescriptor} for the properties currently defined in this DynaClass. If no properties are defined, a zero-length array
    124     * will be returned.
    125     * </p>
    126     *
    127     * <p>
    128     * <strong>FIXME</strong> - Should we really be implementing {@code getBeanInfo()} instead, which returns property descriptors and a bunch of other stuff?
    129     * </p>
    130     *
    131     * @return the set of properties for this DynaClass
    132     */
    133    @Override
    134    public DynaProperty[] getDynaProperties() {
    135        return properties.clone();
    136    }
    137
    138    /**
    139     * Gets a property descriptor for the specified property, if it exists; otherwise, return {@code null}.
    140     *
    141     * @param name Name of the dynamic property for which a descriptor is requested
    142     * @return The descriptor for the specified property
    143     * @throws IllegalArgumentException if no property name is specified
    144     */
    145    @Override
    146    public DynaProperty getDynaProperty(final String name) {
    147        return propertiesMap.get(Objects.requireNonNull(name, "name"));
    148    }
    149
    150    /**
    151     * Gets the name of this DynaClass (analogous to the {@code getName()} method of {@link Class}, which allows the same {@code DynaClass} implementation class
    152     * to support different dynamic classes, with different sets of properties.
    153     *
    154     * @return the name of the DynaClass
    155     */
    156    @Override
    157    public String getName() {
    158        return this.name;
    159    }
    160
    161    /**
    162     * Instantiate and return a new DynaBean instance, associated with this DynaClass.
    163     *
    164     * @return A new {@code DynaBean} instance
    165     * @throws IllegalAccessException if the Class or the appropriate constructor is not accessible
    166     * @throws InstantiationException if this Class represents an abstract class, an array class, a primitive type, or void; or if instantiation fails for some
    167     *                                other reason
    168     */
    169    @Override
    170    public DynaBean newInstance() throws IllegalAccessException, InstantiationException {
    171        try {
    172            // Refind the constructor after a deserialization (if needed)
    173            if (constructor == null) {
    174                setDynaBeanClass(this.dynaBeanClass);
    175            }
    176            // Invoke the constructor to create a new bean instance
    177            return (DynaBean) constructor.newInstance(constructorValues);
    178        } catch (final InvocationTargetException e) {
    179            throw new InstantiationException(e.getTargetException().getMessage());
    180        }
    181    }
    182
    183    /**
    184     * Sets the Class object we will use to create new instances in the {@code newInstance()} method. This Class <strong>MUST</strong> implement the
    185     * {@code DynaBean} interface.
    186     *
    187     * @param dynaBeanClass The new Class object
    188     * @throws IllegalArgumentException if the specified Class does not implement the {@code DynaBean} interface
    189     */
    190    protected void setDynaBeanClass(final Class<?> dynaBeanClass) {
    191        // Validate the argument type specified
    192        if (dynaBeanClass.isInterface()) {
    193            throw new IllegalArgumentException("Class " + dynaBeanClass.getName() + " is an interface, not a class");
    194        }
    195        if (!DynaBean.class.isAssignableFrom(dynaBeanClass)) {
    196            throw new IllegalArgumentException("Class " + dynaBeanClass.getName() + " does not implement DynaBean");
    197        }
    198
    199        // Identify the Constructor we will use in newInstance()
    200        try {
    201            this.constructor = dynaBeanClass.getConstructor(CONSTRUCTOR_TYPES);
    202        } catch (final NoSuchMethodException e) {
    203            throw new IllegalArgumentException("Class " + dynaBeanClass.getName() + " does not have an appropriate constructor");
    204        }
    205        this.dynaBeanClass = dynaBeanClass;
    206    }
    207
    208    /**
    209     * Sets the list of dynamic properties supported by this DynaClass.
    210     *
    211     * @param properties List of dynamic properties to be supported
    212     */
    213    protected void setProperties(final DynaProperty[] properties) {
    214        this.properties = Objects.requireNonNull(properties, "properties");
    215        propertiesMap.clear();
    216        for (final DynaProperty property : properties) {
    217            propertiesMap.put(property.getName(), property);
    218        }
    219    }
    220
    221}