/** * 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.tags;import javax.servlet.jsp.PageContext;import javax.servlet.jsp.tagext.BodyTagSupport;import org.displaytag.exception.ObjectLookupException;import org.displaytag.util.LookupUtil;/** * Base template class. * @author bgsmith * @author Fabrizio Giustina * @version $Revision: 1081 $ ($Author: fgiust $) */public abstract class TemplateTag extends BodyTagSupport{    /**     * <p>     * evaluate an expression in a way similar to LE in jstl.     * </p>     * <p>     * the first token is supposed to be an object in the page scope (default scope) or one of the following:     * </p>     * <ul>     * <li>pageScope</li>     * <li>requestScope</li>     * <li>sessionScope</li>     * <li>applicationScope</li>     * </ul>     * <p>     * Tokens after the object name are interpreted as javabean properties (accessed through getters), mapped or indexed     * properties, using the jakarta common-beans library     * </p>     * @param expression expression to evaluate     * @return Object result     * @throws ObjectLookupException if unable to get a bean using the given expression     */    protected Object evaluateExpression(String expression) throws ObjectLookupException    {        String expressionWithoutScope = expression;        // default scope = request        // this is for compatibility with the previous version, probably default should be PAGE        int scope = PageContext.REQUEST_SCOPE;        if (expression.startsWith("pageScope.")) //$NON-NLS-1$        {            scope = PageContext.PAGE_SCOPE;            expressionWithoutScope = expressionWithoutScope.substring(expressionWithoutScope.indexOf('.') + 1);        }        else if (expression.startsWith("requestScope.")) //$NON-NLS-1$        {            scope = PageContext.REQUEST_SCOPE;            expressionWithoutScope = expressionWithoutScope.substring(expressionWithoutScope.indexOf('.') + 1);        }        else if (expression.startsWith("sessionScope.")) //$NON-NLS-1$        {            scope = PageContext.SESSION_SCOPE;            expressionWithoutScope = expressionWithoutScope.substring(expressionWithoutScope.indexOf('.') + 1);        }        else if (expression.startsWith("applicationScope.")) //$NON-NLS-1$        {            scope = PageContext.APPLICATION_SCOPE;            expressionWithoutScope = expressionWithoutScope.substring(expressionWithoutScope.indexOf('.') + 1);        }        return LookupUtil.getBeanValue(this.pageContext, expressionWithoutScope, scope);    }}