basicdynabean.java

apache beanutils开源项目源码

/*
 * Copyright 2001-2004 The Apache Software Foundation.
 * 
 * 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.apache.commons.beanutils;


import java.io.Serializable;
import java.lang.reflect.Array;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


/**
 * <p>Minimal implementation of the <code>DynaBean</code> interface.  Can be
 * used as a convenience base class for more sophisticated implementations.</p>
 *
 * <p><strong>IMPLEMENTATION NOTE</strong> - Instances of this class that are
 * accessed from multiple threads simultaneously need to be synchronized.</p>
 *
 * <p><strong>IMPLEMENTATION NOTE</strong> - Instances of this class can be
 * successfully serialized and deserialized <strong>ONLY</strong> if all
 * property values are <code>Serializable</code>.</p>
 *
 * @author Craig McClanahan
 * @version $Revision: 1.11 $ $Date: 2004/02/28 13:18:33 $
 */

public class BasicDynaBean implements DynaBean, Serializable {


    // ---------------------------------------------------------- Constructors


    /**
     * Construct a new <code>DynaBean</code> associated with the specified
     * <code>DynaClass</code> instance.
     *
     * @param dynaClass The DynaClass we are associated with
     */
    public BasicDynaBean(DynaClass dynaClass) {

        super();
        this.dynaClass = dynaClass;

    }


    // ---------------------------------------------------- Instance Variables


    /**
     * The <code>DynaClass</code> "base class" that this DynaBean
     * is associated with.
     */
    protected DynaClass dynaClass = null;


    /**
     * The set of property values for this DynaBean, keyed by property name.
     */
    protected HashMap values = new HashMap();


    // ------------------------------------------------------ DynaBean Methods


    /**
     * Does the specified mapped property contain a value for the specified
     * key value?
     *
     * @param name Name of the property to check
     * @param key Name of the key to check
     *
     * @exception IllegalArgumentException if there is no property
     *  of the specified name
     */
    public boolean contains(String name, String key) {

        Object value = values.get(name);
        if (value == null) {
            throw new NullPointerException
                    ("No mapped value for '" + name + "(" + key + ")'");
        } else if (value instanceof Map) {
            return (((Map) value).containsKey(key));
        } else {
            throw new IllegalArgumentException
                    ("Non-mapped property for '" + name + "(" + key + ")'");
        }

    }


    /**
     * Return the value of a simple property with the specified name.
     *
     * @param name Name of the property whose value is to be retrieved
     *
     * @exception IllegalArgumentException if there is no property
     *  of the specified name
     */
    public Object get(String name) {

        // Return any non-null value for the specified property
        Object value = values.get(name);
        if (value != null) {
            return (value);
        }

        // Return a null value for a non-primitive property
        Class type = getDynaProperty(name).getType();
        if (!type.isPrimitive()) {
            return (value);
        }

        // Manufacture default values for primitive properties
        if (type == Boolean.TYPE) {
            return (Boolean.FALSE);
        } else if (type == Byte.TYPE) {
            return (new Byte((byte) 0));
        } else if (type == Character.TYPE) {
            return (new Character((char) 0));
        } else if (type == Double.TYPE) {
            return (new Double((double) 0.0));
        } else if (type == Float.TYPE) {
            return (new Float((float) 0.0));
        } else if (type == Integer.TYPE) {
            return (new Integer((int) 0));
        } else if (type == Long.TYPE) {
            return (new Long((int) 0));
        } else if (type == Short.TYPE) {
            return (new Short((short) 0));
        } else {
            return (null);
        }

    }


    /**
     * Return the value of an indexed property with the specified name.
     *
     * @param name Name of the property whose value is to be retrieved
     * @param index Index of the value to be retrieved
     *
     * @exception IllegalArgumentException if there is no property
     *  of the specified name
     * @exception IllegalArgumentException if the specified property
     *  exists, but is not indexed
     * @exception IndexOutOfBoundsException if the specified index
     *  is outside the range of the underlying property
     * @exception NullPointerException if no array or List has been
     *  initialized for this property
     */
    public Object get(String name, int index) {

        Object value = values.get(name);
        if (value == null) {
            throw new NullPointerException
                    ("No indexed value for '" + name + "[" + index + "]'");
        } else if (value.getClass().isArray()) {
            return (Array.get(value, index));
        } else if (value instanceof List) {
            return ((List) value).get(index);
        } else {
            throw new IllegalArgumentException
                    ("Non-indexed property for '" + name + "[" + index + "]'");
        }

    }


    /**
     * Return the value of a mapped property with the specified name,
     * or <code>null</code> if there is no value for the specified key.
     *
     * @param name Name of the property whose value is to be retrieved
     * @param key Key of the value to be retrieved
     *
     * @exception IllegalArgumentException if there is no property
     *  of the specified name
     * @exception IllegalArgumentException if the specified property
     *  exists, but is not mapped
     */
    public Object get(String name, String key) {

        Object value = values.get(name);
        if (value == null) {
            throw new NullPointerException
                    ("No mapped value for '" + name + "(" + key + ")'");
        } else if (value instanceof Map) {
            return (((Map) value).get(key));
        } else {
            throw new IllegalArgumentException
                    ("Non-mapped property for '" + name + "(" + key + ")'");
        }

    }


    /**
     * Return the <code>DynaClass</code> instance that describes the set of
     * properties available for this DynaBean.
     */
    public DynaClass getDynaClass() {

        return (this.dynaClass);

    }


    /**
     * Remove any existing value for the specified key on the
     * specified mapped property.
     *
     * @param name Name of the property for which a value is to
     *  be removed
     * @param key Key of the value to be removed
     *
     * @exception IllegalArgumentException if there is no property
     *  of the specified name
     */
    public void remove(String name, String key) {

        Object value = values.get(name);
        if (value == null) {
            throw new NullPointerException
                    ("No mapped value for '" + name + "(" + key + ")'");
        } else if (value instanceof Map) {
            ((Map) value).remove(key);
        } else {
            throw new IllegalArgumentException
                    ("Non-mapped property for '" + name + "(" + key + ")'");
        }

    }


    /**
     * Set the value of a simple property with the specified name.
     *
     * @param name Name of the property whose value is to be set
     * @param value Value to which this property is to be set
     *
     * @exception ConversionException if the specified value cannot be
     *  converted to the type required for this property
     * @exception IllegalArgumentException if there is no property
     *  of the specified name
     * @exception NullPointerException if an attempt is made to set a
     *  primitive property to null
     */
    public void set(String name, Object value) {

        DynaProperty descriptor = getDynaProperty(name);
        if (value == null) {
            if (descriptor.getType().isPrimitive()) {
                throw new NullPointerException
                        ("Primitive value for '" + name + "'");
            }
        } else if (!isAssignable(descriptor.getType(), value.getClass())) {
            throw new ConversionException
                    ("Cannot assign value of type '" +
                    value.getClass().getName() +
                    "' to property '" + name + "' of type '" +
                    descriptor.getType().getName() + "'");
        }
        values.put(name, value);

    }


    /**
     * Set the value of an indexed property with the specified name.
     *
     * @param name Name of the property whose value is to be set
     * @param index Index of the property to be set
     * @param value Value to which this property is to be set
     *
     * @exception ConversionException if the specified value cannot be
     *  converted to the type required for this property
     * @exception IllegalArgumentException if there is no property
     *  of the specified name
     * @exception IllegalArgumentException if the specified property
     *  exists, but is not indexed
     * @exception IndexOutOfBoundsException if the specified index
     *  is outside the range of the underlying property
     */
    public void set(String name, int index, Object value) {

        Object prop = values.get(name);
        if (prop == null) {
            throw new NullPointerException
                    ("No indexed value for '" + name + "[" + index + "]'");
        } else if (prop.getClass().isArray()) {
            Array.set(prop, index, value);
        } else if (prop instanceof List) {
            try {
                ((List) prop).set(index, value);
            } catch (ClassCastException e) {
                throw new ConversionException(e.getMessage());
            }
        } else {
            throw new IllegalArgumentException
                    ("Non-indexed property for '" + name + "[" + index + "]'");
        }

    }


    /**
     * Set the value of a mapped property with the specified name.
     *
     * @param name Name of the property whose value is to be set
     * @param key Key of the property to be set
     * @param value Value to which this property is to be set
     *
     * @exception ConversionException if the specified value cannot be
     *  converted to the type required for this property
     * @exception IllegalArgumentException if there is no property
     *  of the specified name
     * @exception IllegalArgumentException if the specified property
     *  exists, but is not mapped
     */
    public void set(String name, String key, Object value) {

        Object prop = values.get(name);
        if (prop == null) {
            throw new NullPointerException
                    ("No mapped value for '" + name + "(" + key + ")'");
        } else if (prop instanceof Map) {
            ((Map) prop).put(key, value);
        } else {
            throw new IllegalArgumentException
                    ("Non-mapped property for '" + name + "(" + key + ")'");
        }

    }


    // ------------------------------------------------------ Protected Methods


    /**
     * Return the property descriptor for the specified property name.
     *
     * @param name Name of the property for which to retrieve the descriptor
     *
     * @exception IllegalArgumentException if this is not a valid property
     *  name for our DynaClass
     */
    protected DynaProperty getDynaProperty(String name) {

        DynaProperty descriptor = getDynaClass().getDynaProperty(name);
        if (descriptor == null) {
            throw new IllegalArgumentException
                    ("Invalid property name '" + name + "'");
        }
        return (descriptor);

    }


    /**
     * Is an object of the source class assignable to the destination class?
     *
     * @param dest Destination class
     * @param source Source class
     */
    protected boolean isAssignable(Class dest, Class source) {

        if (dest.isAssignableFrom(source) ||
                ((dest == Boolean.TYPE) && (source == Boolean.class)) ||
                ((dest == Byte.TYPE) && (source == Byte.class)) ||
                ((dest == Character.TYPE) && (source == Character.class)) ||
                ((dest == Double.TYPE) && (source == Double.class)) ||
                ((dest == Float.TYPE) && (source == Float.class)) ||
                ((dest == Integer.TYPE) && (source == Integer.class)) ||
                ((dest == Long.TYPE) && (source == Long.class)) ||
                ((dest == Short.TYPE) && (source == Short.class))) {
            return (true);
        } else {
            return (false);
        }

    }


}