lazydynabean.java

这是一个有关common beanutils 的源码

                    Array.set(indexedProperty, i, createProperty(name+"["+i+"]", componentType));
                }
            }
        }

        return indexedProperty;

    }

    /**
     * Create a new Instance of a Property
     * @param name The name of the property
     * @param type The class of the property
     * @return The new value
     */
    protected Object createProperty(String name, Class type) {
        if (type == null) {
            return null;
        }

        // Create Lists, arrays or DynaBeans
        if (type.isArray() || List.class.isAssignableFrom(type)) {
            return createIndexedProperty(name, type);
        }

        if (Map.class.isAssignableFrom(type)) {
            return createMappedProperty(name, type);
        }

        if (DynaBean.class.isAssignableFrom(type)) {
            return createDynaBeanProperty(name, type);
        }

        if (type.isPrimitive()) {
            return createPrimitiveProperty(name, type);
        }

        if (Number.class.isAssignableFrom(type)) {
            return createNumberProperty(name, type);
        }

        return createOtherProperty(name, type);

    }

    /**
     * Create a new Instance of an 'Indexed' Property
     * @param name The name of the property
     * @param type The class of the property
     * @return The new value
     */
    protected Object createIndexedProperty(String name, Class type) {

        // Create the indexed object
        Object indexedProperty = null;

        if (type == null) {

            indexedProperty = defaultIndexedProperty(name);

        } else if (type.isArray()) {

            indexedProperty = Array.newInstance(type.getComponentType(), 0);

        } else if (List.class.isAssignableFrom(type)) {
            if (type.isInterface()) {
                indexedProperty = defaultIndexedProperty(name);
            } else {
                try {
                    indexedProperty = type.newInstance();
                }
                catch (Exception ex) {
                    throw new IllegalArgumentException
                        ("Error instantiating indexed property of type '" +
                                   type.getName() + "' for '" + name + "' " + ex);
                }
            }
        } else {

            throw new IllegalArgumentException
                    ("Non-indexed property of type '" + type.getName() + "' for '" + name + "'");
        }

        return indexedProperty;

    }

    /**
     * Create a new Instance of a 'Mapped' Property
     * @param name The name of the property
     * @param type The class of the property
     * @return The new value
     */
    protected Object createMappedProperty(String name, Class type) {

        // Create the mapped object
        Object mappedProperty = null;

        if (type == null) {

            mappedProperty = defaultMappedProperty(name);

        } else if (type.isInterface()) {

            mappedProperty = defaultMappedProperty(name);

        } else if (Map.class.isAssignableFrom(type)) {
            try {
                mappedProperty = type.newInstance();
            }
            catch (Exception ex) {
                throw new IllegalArgumentException
                    ("Error instantiating mapped property of type '" +
                            type.getName() + "' for '" + name + "' " + ex);
            }
        } else {

            throw new IllegalArgumentException
                    ("Non-mapped property of type '" + type.getName() + "' for '" + name + "'");
        }

        return mappedProperty;

    }

    /**
     * Create a new Instance of a 'DynaBean' Property.
     * @param name The name of the property
     * @param type The class of the property
     * @return The new value
     */
    protected Object createDynaBeanProperty(String name, Class type) {
        try {
            return type.newInstance();
        }
        catch (Exception ex) {
            if (logger().isWarnEnabled()) {
                logger().warn("Error instantiating DynaBean property of type '" +
                        type.getName() + "' for '" + name + "' " + ex);
            }
            return null;
        }
    }

    /**
     * Create a new Instance of a 'Primitive' Property.
     * @param name The name of the property
     * @param type The class of the property
     * @return The new value
     */
    protected Object createPrimitiveProperty(String name, Class type) {

        if (type == Boolean.TYPE) {
            return Boolean.FALSE;
        } else if (type == Integer.TYPE) {
            return Integer_ZERO;
        } else if (type == Long.TYPE) {
            return Long_ZERO;
        } else if (type == Double.TYPE) {
            return Double_ZERO;
        } else if (type == Float.TYPE) {
            return Float_ZERO;
        } else if (type == Byte.TYPE) {
            return Byte_ZERO;
        } else if (type == Short.TYPE) {
            return Short_ZERO;
        } else if (type == Character.TYPE) {
            return Character_SPACE;
        } else {
            return null;
        }

    }

    /**
     * Create a new Instance of a <code>java.lang.Number</code> Property.
     * @param name The name of the property
     * @param type The class of the property
     * @return The new value
     */
    protected Object createNumberProperty(String name, Class type) {

        return null;

    }

    /**
     * Create a new Instance of other Property types
     * @param name The name of the property
     * @param type The class of the property
     * @return The new value
     */
    protected Object createOtherProperty(String name, Class type) {

        if (type == Object.class    ||
            type == String.class    ||
            type == Boolean.class   ||
            type == Character.class ||
            Date.class.isAssignableFrom(type)) {

            return null;

        }

        try {
            return type.newInstance();
        }
        catch (Exception ex) {
            if (logger().isWarnEnabled()) {
                logger().warn("Error instantiating property of type '" + type.getName() + "' for '" + name + "' " + ex);
            }
            return null;
        }
    }

    /**
     * <p>Creates a new <code>ArrayList</code> for an 'indexed' property
     *    which doesn't exist.</p>
     *
     * <p>This method shouls be overriden if an alternative <code>List</code>
     *    or <code>Array</code> implementation is required for 'indexed' properties.</p>
     *
     * @param name Name of the 'indexed property.
     * @return The default value for an indexed property (java.util.ArrayList)
     */
    protected Object defaultIndexedProperty(String name) {
        return new ArrayList();
    }

    /**
     * <p>Creates a new <code>HashMap</code> for a 'mapped' property
     *    which doesn't exist.</p>
     *
     * <p>This method can be overriden if an alternative <code>Map</code>
     *    implementation is required for 'mapped' properties.</p>
     *
     * @param name Name of the 'mapped property.
     * @return The default value for a mapped property (java.util.HashMap)
     */
    protected Map defaultMappedProperty(String name) {
        return new HashMap();
    }

    /**
     * Indicates if there is a property with the specified name.
     * @param name The name of the property to check
     * @return <code>true<code> if there is a property of the
     * specified name, otherwise <code>false</code>
     */
    protected boolean isDynaProperty(String name) {

        if (name == null) {
            throw new IllegalArgumentException("No property name specified");
        }

        // Handle LazyDynaClasses
        if (dynaClass instanceof LazyDynaClass) {
            return ((LazyDynaClass)dynaClass).isDynaProperty(name);
        }

        // Handle other MutableDynaClass
        return dynaClass.getDynaProperty(name) == null ? false : true;

    }

    /**
     * Is an object of the source class assignable to the destination class?
     *
     * @param dest Destination class
     * @param source Source class
     * @return <code>true<code> if the source class is assignable to the
     * destination class, otherwise <code>false</code>
     */
    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);
        }

    }

    /**
     * <p>Creates a new instance of the <code>Map</code>.</p>
     * @return a new Map instance
     */
    protected Map newMap() {
        return new HashMap();
    }

    /**
     * <p>Returns the <code>Log</code>.
     */
    private Log logger() {
        if (logger == null) {
            logger = LogFactory.getLog(LazyDynaBean.class);
        }
        return logger;
    }

}