/*

  * 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.beanutils;

 /**

  * <p>DynaClass which implements the <code>MutableDynaClass</code> interface.</p>

  *

  * <p>A <code>MutableDynaClass</code> is a specialized extension to <code>DynaClass</code>

  *    that allows properties to be added or removed dynamically.</p>

  *

  * <p>This implementation has one slightly unusual default behaviour - calling

  *    the <code>getDynaProperty(name)</code> method for a property which doesn't

  *    exist returns a <code>DynaProperty</code> rather than <code>null</code>. The

  *    reason for this is that <code>BeanUtils</code> calls this method to check if

  *    a property exists before trying to set the value. This would defeat the object

  *    of the <code>LazyDynaBean</code> which automatically adds missing properties

  *    when any of its <code>set()</code> methods are called. For this reason the

  *    <code>isDynaProperty(name)</code> method has been added to this implementation

  *    in order to determine if a property actually exists. If the more <i>normal</i>

  *    behaviour of returning <code>null</code> is required, then this can be achieved

  *    by calling the <code>setReturnNull(true)</code>.</p>

  *

  * <p>The <code>add(name, type, readable, writable)</code> method is not implemented

  *    and always throws an <code>UnsupportedOperationException</code>. I believe

  *    this attributes need to be added to the <code>DynaProperty</code> class

  *    in order to control read/write facilities.</p>

  *

  * @see LazyDynaBean

  * @author Niall Pemberton

  */

 public class LazyDynaClass extends BasicDynaClass implements MutableDynaClass  {

     /**

      * Controls whether changes to this DynaClass's properties are allowed.

      */

     protected boolean restricted;

     /**

      * <p>Controls whether the <code>getDynaProperty()</code> method returns

      * null if a property doesn't exist - or creates a new one.</p>

      *

      * <p>Default is <code>false</code>.

      */

     protected boolean returnNull = false;

     /**

      * Construct a new LazyDynaClass with default parameters.

      */

     public LazyDynaClass() {

         this(null, (DynaProperty[])null);

     }

     /**

      * Construct a new LazyDynaClass with the specified name.

      *

      * @param name Name of this DynaBean class

      */

     public LazyDynaClass(String name) {

         this(name, (DynaProperty[])null);

     }

     /**

      * Construct a new LazyDynaClass with the specified name and DynaBean class.

      *

      * @param name Name of this DynaBean class

      * @param dynaBeanClass The implementation class for new instances

      */

     public LazyDynaClass(String name, Class dynaBeanClass) {

         this(name, dynaBeanClass, null);

     }

     /**

      * Construct a new LazyDynaClass with the specified name and properties.

      *

      * @param name Name of this DynaBean class

      * @param properties Property descriptors for the supported properties

      */

     public LazyDynaClass(String name, DynaProperty[] properties) {

         this(name, LazyDynaBean.class, properties);

     }

     /**

      * Construct a new LazyDynaClass with the specified name, DynaBean class and properties.

      *

      * @param name Name of this DynaBean class

      * @param dynaBeanClass The implementation class for new intances

      * @param properties Property descriptors for the supported properties

      */

     public LazyDynaClass(String name, Class dynaBeanClass, DynaProperty properties[]) {

         super(name, dynaBeanClass, properties);

     }

     /**

      * <p>Is this DynaClass currently restricted.</p>

      * <p>If restricted, no changes to the existing registration of

      *  property names, data types, readability, or writeability are allowed.</p>

      * @return <code>true</code> if this {@link MutableDynaClass} cannot be changed

      * otherwise <code>false</code>

      */

     public boolean isRestricted() {

         return restricted;

     }

     /**

      * <p>Set whether this DynaClass is currently restricted.</p>

      * <p>If restricted, no changes to the existing registration of

      *  property names, data types, readability, or writeability are allowed.</p>

      * @param restricted <code>true</code> if this {@link MutableDynaClass} cannot

      * be changed otherwise <code>false</code>

      */

     public void setRestricted(boolean restricted) {

         this.restricted = restricted;

     }

     /**

      * Should this DynaClass return a <code>null</code> from

      * the <code>getDynaProperty(name)</code> method if the property

      * doesn't exist.

      *

      * @return <code>true<code> if a <code>null</code> {@link DynaProperty}

      * should be returned if the property doesn't exist, otherwise

      * <code>false</code> if a new {@link DynaProperty} should be created.

      */

     public boolean isReturnNull() {

         return returnNull;

     }

     /**

      * Set whether this DynaClass should return a <code>null</code> from

      * the <code>getDynaProperty(name)</code> method if the property

      * doesn't exist.

      * @param returnNull <code>true<code> if a <code>null</code> {@link DynaProperty}

      * should be returned if the property doesn't exist, otherwise

      * <code>false</code> if a new {@link DynaProperty} should be created.

      */

     public void setReturnNull(boolean returnNull) {

         this.returnNull = returnNull;

     }

     /**

      * Add a new dynamic property with no restrictions on data type,

      * readability, or writeability.

      *

      * @param name Name of the new dynamic property

      *

      * @exception IllegalArgumentException if name is null

      * @exception IllegalStateException if this DynaClass is currently

      *  restricted, so no new properties can be added

      */

     public void add(String name) {

         add(new DynaProperty(name));

     }

     /**

      * Add a new dynamic property with the specified data type, but with

      * no restrictions on readability or writeability.

      *

      * @param name Name of the new dynamic property

      * @param type Data type of the new dynamic property (null for no

      *  restrictions)

      *

      * @exception IllegalArgumentException if name is null

      * @exception IllegalStateException if this DynaClass is currently

      *  restricted, so no new properties can be added

      */

     public void add(String name, Class type) {

         if (type == null) {

             add(name);

         } else {

             add(new DynaProperty(name, type));

         }

     }

     /**

      * <p>Add a new dynamic property with the specified data type, readability,

      * and writeability.</p>

      *

      * <p><strong>N.B.</strong>Support for readable/writeable properties has not been implemented

      *    and this method always throws a <code>UnsupportedOperationException</code>.</p>

      *

      * <p>I'm not sure the intention of the original authors for this method, but it seems to

      *    me that readable/writable should be attributes of the <code>DynaProperty</code> class

      *    (which they are not) and is the reason this method has not been implemented.</p>

      *

      * @param name Name of the new dynamic property

      * @param type Data type of the new dynamic property (null for no

      *  restrictions)

      * @param readable Set to <code>true</code> if this property value

      *  should be readable

      * @param writeable Set to <code>true</code> if this property value

      *  should be writeable

      *

      * @exception UnsupportedOperationException anytime this method is called

      */

     public void add(String name, Class type, boolean readable, boolean writeable) {

         throw new java.lang.UnsupportedOperationException("readable/writable properties not supported");

     }

     /**

      * Add a new dynamic property.

      *

      * @param property Property the new dynamic property to add.

      *

      * @exception IllegalArgumentException if name is null

      * @exception IllegalStateException if this DynaClass is currently

      *  restricted, so no new properties can be added

      */

     protected void add(DynaProperty property) {

         if (property.getName() == null) {

             throw new IllegalArgumentException("Property name is missing.");

         }

         if (isRestricted()) {

             throw new IllegalStateException("DynaClass is currently restricted. No new properties can be added.");

         }

         // Check if property already exists

         if (propertiesMap.get(property.getName()) != null) {

            return;

         }

         // Create a new property array with the specified property

         DynaProperty[] oldProperties = getDynaProperties();

         DynaProperty[] newProperties = new DynaProperty[oldProperties.length+1];

         System.arraycopy(oldProperties, 0, newProperties, 0, oldProperties.length);

         newProperties[oldProperties.length] = property;

        // Update the properties

        setProperties(newProperties);

     }

     /**

      * Remove the specified dynamic property, and any associated data type,

      * readability, and writeability, from this dynamic class.

      * <strong>NOTE</strong> - This does <strong>NOT</strong> cause any

      * corresponding property values to be removed from DynaBean instances

      * associated with this DynaClass.

      *

      * @param name Name of the dynamic property to remove

      *

      * @exception IllegalArgumentException if name is null

      * @exception IllegalStateException if this DynaClass is currently

      *  restricted, so no properties can be removed

      */

     public void remove(String name) {

         if (name == null) {

             throw new IllegalArgumentException("Property name is missing.");

         }

         if (isRestricted()) {

             throw new IllegalStateException("DynaClass is currently restricted. No properties can be removed.");

         }

         // Ignore if property doesn't exist

         if (propertiesMap.get(name) == null) {

             return;

         }

         // Create a new property array of without the specified property

         DynaProperty[] oldProperties = getDynaProperties();

         DynaProperty[] newProperties = new DynaProperty[oldProperties.length-1];

         int j = 0;

         for (int i = 0; i < oldProperties.length; i++) {

             if (!(name.equals(oldProperties[i].getName()))) {

                 newProperties[j] = oldProperties[i];

                 j++;

             }

         }

         // Update the properties

         setProperties(newProperties);

     }

     /**

      * <p>Return a property descriptor for the specified property.</p>

      *

      * <p>If the property is not found and the <code>returnNull</code> indicator is

      *    <code>true</code>, this method always returns <code>null</code>.</p>

      *

      * <p>If the property is not found and the <code>returnNull</code> indicator is

      *    <code>false</code> a new property descriptor is created and returned (although

      *    its not actually added to the DynaClass's properties). This is the default

      *    beahviour.</p>

      *

      * <p>The reason for not returning a <code>null</code> property descriptor is that

      *    <code>BeanUtils</code> uses this method to check if a property exists

      *    before trying to set it - since these <i>Lazy</i> implementations automatically

      *    add any new properties when they are set, returning <code>null</code> from

      *    this method would defeat their purpose.</p>

      *

      * @param name Name of the dynamic property for which a descriptor

      *  is requested

      * @return The dyna property for the specified name

      *

      * @exception IllegalArgumentException if no property name is specified

      */

     public DynaProperty getDynaProperty(String name) {

         if (name == null) {

             throw new IllegalArgumentException("Property name is missing.");

         }

         DynaProperty dynaProperty = (DynaProperty)propertiesMap.get(name);

         // If it doesn't exist and returnNull is false

         // create a new DynaProperty

         if (dynaProperty == null && !isReturnNull() && !isRestricted()) {

             dynaProperty = new DynaProperty(name);

         }

         return dynaProperty;

     }

     /**

      * <p>Indicate whether a property actually exists.</p>

      *

      * <p><strong>N.B.</strong> Using <code>getDynaProperty(name) == null</code>

      * doesn't work in this implementation because that method might

      * return a DynaProperty if it doesn't exist (depending on the

      * <code>returnNull</code> indicator).</p>

      *

      * @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>

      * @exception IllegalArgumentException if no property name is specified

      */

     public boolean isDynaProperty(String name) {

         if (name == null) {

             throw new IllegalArgumentException("Property name is missing.");

         }

         return propertiesMap.get(name) ==  null ? false : true;

     }

 }