/** * Licensed under the Artistic License; you may not use this file * except in compliance with the License. * You may obtain a copy of the License at * *      http://displaytag.sourceforge.net/license.html * * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. */package org.displaytag.decorator;import javax.servlet.jsp.PageContext;import org.apache.commons.lang.StringUtils;import org.displaytag.exception.DecoratorException;import org.displaytag.exception.DecoratorInstantiationException;import org.displaytag.properties.MediaTypeEnum;import org.displaytag.util.ReflectHelper;/** * Factory for TableDecorator or ColumnDecorator object. * @author Fabrizio Giustina * @version $Id$ */public class DefaultDecoratorFactory implements DecoratorFactory{    /**     * <p>     * If the user has specified a decorator, then this method takes care of creating the decorator (and checking to     * make sure it is a subclass of the TableDecorator object). If there are any problems loading the decorator then     * this will throw a DecoratorInstantiationException which will get propagated up to the page.     * </p>     * <p>     * Two different methods for loading a decorator are handled by this factory:     * </p>     * <ul>     * <li>First of all, an object with key <code>decoratorName</code> is searched in the page/request/session/scope</li>     * <li>If not found, assume <code>decoratorName</code> is the class name of the decorator and load it using     * reflection</li>     * </ul>     * @param decoratorName String full decorator class name     * @return instance of TableDecorator     * @throws DecoratorInstantiationException if unable to load specified TableDecorator     */    public TableDecorator loadTableDecorator(PageContext pageContext, String decoratorName)        throws DecoratorInstantiationException    {        if (StringUtils.isBlank(decoratorName))        {            return null;        }        // first check: is decoratorName an object in page/request/session/application scope?        Object decorator = pageContext.findAttribute(decoratorName);        // second check: if a decorator was not found assume decoratorName is the class name and load it using        // reflection        if (decorator == null)        {            try            {                decorator = ReflectHelper.classForName(decoratorName).newInstance();            }            catch (ClassNotFoundException e)            {                throw new DecoratorInstantiationException(DefaultDecoratorFactory.class, decoratorName, e);            }            catch (InstantiationException e)            {                throw new DecoratorInstantiationException(DefaultDecoratorFactory.class, decoratorName, e);            }            catch (IllegalAccessException e)            {                throw new DecoratorInstantiationException(DefaultDecoratorFactory.class, decoratorName, e);            }        }        if (decorator instanceof TableDecorator)        {            return (TableDecorator) decorator;        }        else        {            throw new DecoratorInstantiationException(                DefaultDecoratorFactory.class,                decoratorName,                new ClassCastException(decorator.getClass().getName()));        }    }    /**     * <p>     * If the user has specified a column decorator, then this method takes care of creating the decorator (and checking     * to make sure it is a subclass of the DisplaytagColumnDecorator object). If there are any problems loading the     * decorator then this will throw a DecoratorInstantiationException which will get propagated up to the page.     * </p>     * <p>     * Two different methods for loading a decorator are handled by this factory:     * </p>     * <ul>     * <li>First of all, an object with key <code>decoratorName</code> is searched in the page/request/session/scope</li>     * <li>If not found, assume <code>decoratorName</code> is the class name of the decorator and load it using     * reflection</li>     * </ul>     * @param decoratorName String full decorator class name     * @return instance of DisplaytagColumnDecorator     * @throws DecoratorInstantiationException if unable to load ColumnDecorator     */    public DisplaytagColumnDecorator loadColumnDecorator(PageContext pageContext, String decoratorName)        throws DecoratorInstantiationException    {        if (StringUtils.isBlank(decoratorName))        {            return null;        }        // first check: is decoratorName an object in page/request/session/application scope?        Object decorator = pageContext.findAttribute(decoratorName);        // second check: if a decorator was not found assume decoratorName is the class name and load it using        // reflection        if (decorator == null)        {            try            {                decorator = ReflectHelper.classForName(decoratorName).newInstance();            }            catch (ClassNotFoundException e)            {                throw new DecoratorInstantiationException(DefaultDecoratorFactory.class, decoratorName, e);            }            catch (InstantiationException e)            {                throw new DecoratorInstantiationException(DefaultDecoratorFactory.class, decoratorName, e);            }            catch (IllegalAccessException e)            {                throw new DecoratorInstantiationException(DefaultDecoratorFactory.class, decoratorName, e);            }        }        if (decorator instanceof DisplaytagColumnDecorator)        {            return (DisplaytagColumnDecorator) decorator;        }        else if (decorator instanceof ColumnDecorator)        {            return new DeprecatedDecoratorWrapper((ColumnDecorator) decorator);        }        else        {            throw new DecoratorInstantiationException(                DefaultDecoratorFactory.class,                decoratorName,                new ClassCastException(decorator.getClass().getName()));        }    }    /**     * Wrapper class for handling decorators implementing the deprecated ColumnDecorator interface as 1.1     * <code>DisplaytagColumnDecorator</code>s.     */    private static class DeprecatedDecoratorWrapper implements DisplaytagColumnDecorator    {        /**         * Wrapped 1.0 decorator.         */        private ColumnDecorator decorator;        /**         * Instantiates a new wrapper for old decorators.         * @param decorator ColumnDecorator instance         */        public DeprecatedDecoratorWrapper(ColumnDecorator decorator)        {            this.decorator = decorator;        }        /**         * @see org.displaytag.decorator.DisplaytagColumnDecorator#decorate(Object, PageContext, MediaTypeEnum)         * @deprecated         */        public Object decorate(Object columnValue, PageContext pageContext, MediaTypeEnum media)            throws DecoratorException        {            return decorator.decorate(columnValue);        }    }}