/*
* $Id: TagUtils.java 471754 2006-11-06 14:55:09Z husted $
*
* 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.struts.tiles.taglib.util;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;
import java.util.HashMap;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.PageContext;
import org.apache.commons.beanutils.PropertyUtils;
import org.apache.struts.Globals;
import org.apache.struts.tiles.taglib.ComponentConstants;
import org.apache.struts.tiles.ComponentContext;
import org.apache.struts.tiles.ComponentDefinition;
import org.apache.struts.tiles.DefinitionsFactoryException;
import org.apache.struts.tiles.FactoryNotFoundException;
import org.apache.struts.tiles.NoSuchDefinitionException;
import org.apache.struts.tiles.TilesUtil;
/**
* Collection of utilities.
* This class also serves as an interface between Components and Struts. If
* you want to rip away Struts, simply reimplement some methods in this class.
* You can copy them from Struts.
*
*/
public class TagUtils {
/** Debug flag */
public static final boolean debug = true;
/**
* Maps lowercase JSP scope names to their PageContext integer constant
* values.
*/
private static final Map scopes = new HashMap();
/**
* Initialize the scope names map and the encode variable with the
* Java 1.4 method if available.
*/
static {
scopes.put("page", new Integer(PageContext.PAGE_SCOPE));
scopes.put("request", new Integer(PageContext.REQUEST_SCOPE));
scopes.put("session", new Integer(PageContext.SESSION_SCOPE));
scopes.put("application", new Integer(PageContext.APPLICATION_SCOPE));
}
/**
* Get scope value from string value
* @param scopeName Scope as a String.
* @param defaultValue Returned default value, if not found.
* @return Scope as an <code>int</code>, or <code>defaultValue</code> if scope is <code>null</code>.
* @throws JspException Scope name is not recognized as a valid scope.
*/
public static int getScope(String scopeName, int defaultValue) throws JspException {
if (scopeName == null) {
return defaultValue;
}
if (scopeName.equalsIgnoreCase("component")) {
return ComponentConstants.COMPONENT_SCOPE;
} else if (scopeName.equalsIgnoreCase("template")) {
return ComponentConstants.COMPONENT_SCOPE;
} else if (scopeName.equalsIgnoreCase("tile")) {
return ComponentConstants.COMPONENT_SCOPE;
} else {
return getScope(scopeName);
}
}
/**
* Converts the scope name into its corresponding PageContext constant value.
* @param scopeName Can be "page", "request", "session", or "application" in any
* case.
* @return The constant representing the scope (ie. PageContext.REQUEST_SCOPE).
* @throws JspException if the scopeName is not a valid name.
*/
public static int getScope(String scopeName) throws JspException {
Integer scope = (Integer) scopes.get(scopeName.toLowerCase());
if (scope == null) {
//throw new JspException(messages.getMessage("lookup.scope", scope));
throw new JspException("Unable to retrieve the scope "+scopeName);
}
return scope.intValue();
}
/**
* Retrieve bean from page context, using specified scope.
* If scope is not set, use <code>findAttribute()</code>.
*
* @param beanName Name of bean to retrieve.
* @param scopeName Scope or <code>null</code>. If <code>null</code>, bean is searched using
* findAttribute().
* @param pageContext Current pageContext.
* @return Requested bean or <code>null</code> if not found.
* @throws JspException Scope name is not recognized as a valid scope.
*/
public static Object retrieveBean(String beanName, String scopeName, PageContext pageContext)
throws JspException {
if (scopeName == null) {
return findAttribute(beanName, pageContext);
}
// Default value doesn't matter because we have already check it
int scope = getScope(scopeName, PageContext.PAGE_SCOPE);
//return pageContext.getAttribute( beanName, scope );
return getAttribute(beanName, scope, pageContext);
}
/**
* Search attribute in different contexts.
* First, check in component context, then use pageContext.findAttribute().
* @param beanName Name of bean to retrieve.
* @param pageContext Current pageContext.
* @return Requested bean or <code>null</code> if not found.
*/
public static Object findAttribute(String beanName, PageContext pageContext) {
ComponentContext compContext = ComponentContext.getContext(pageContext.getRequest());
if (compContext != null) {
Object attribute = compContext.findAttribute(beanName, pageContext);
if (attribute != null) {
return attribute;
}
}
// Search in pageContext scopes
return pageContext.findAttribute(beanName);
}
/**
* Get object from requested context. Return <code>null</code> if not found.
* Context can be "component" or normal JSP contexts.
* @param beanName Name of bean to retrieve.
* @param scope Scope from which bean must be retrieved.
* @param pageContext Current pageContext.
* @return Requested bean or <code>null</code> if not found.
*/
public static Object getAttribute(String beanName, int scope, PageContext pageContext) {
if (scope == ComponentConstants.COMPONENT_SCOPE) {
ComponentContext compContext = ComponentContext.getContext(pageContext.getRequest());
return compContext.getAttribute(beanName);
}
return pageContext.getAttribute(beanName, scope);
}
/**
* Locate and return the specified property of the specified bean, from
* an optionally specified scope, in the specified page context.
*
* @param pageContext Page context to be searched.
* @param beanName Name of the bean to be retrieved.
* @param beanProperty Name of the property to be retrieved, or
* <code>null</code> to retrieve the bean itself.
* @param beanScope Scope to be searched (page, request, session, application)
* or <code>null</code> to use <code>findAttribute()</code> instead.
*
* @exception JspException Scope name is not recognized as a valid scope
* @exception JspException if the specified bean is not found
* @exception JspException if accessing this property causes an
* IllegalAccessException, IllegalArgumentException,
* InvocationTargetException, or NoSuchMethodException
*/
public static Object getRealValueFromBean(
String beanName,
String beanProperty,
String beanScope,
PageContext pageContext)
throws JspException {
try {
Object realValue;
Object bean = retrieveBean(beanName, beanScope, pageContext);
if (bean != null && beanProperty != null) {
realValue = PropertyUtils.getProperty(bean, beanProperty);
} else {
realValue = bean; // value can be null
}
return realValue;
} catch (NoSuchMethodException ex) {
throw new JspException(
"Error - component.PutAttributeTag : Error while retrieving value from bean '"
+ beanName
+ "' with property '"
+ beanProperty
+ "' in scope '"
+ beanScope
+ "'. (exception : "
+ ex.getMessage(), ex);
} catch (InvocationTargetException ex) {
throw new JspException(
"Error - component.PutAttributeTag : Error while retrieving value from bean '"
+ beanName
+ "' with property '"
+ beanProperty
+ "' in scope '"
+ beanScope
+ "'. (exception : "
+ ex.getMessage(), ex);
} catch (IllegalAccessException ex) {
throw new JspException(
"Error - component.PutAttributeTag : Error while retrieving value from bean '"
+ beanName
+ "' with property '"
+ beanProperty
+ "' in scope '"
+ beanScope
+ "'. (exception : "
+ ex.getMessage(), ex);
}
}
/**
* Store bean in requested context.
* If scope is <code>null</code>, save it in REQUEST_SCOPE context.
*
* @param pageContext Current pageContext.
* @param name Name of the bean.
* @param scope Scope under which bean is saved (page, request, session, application)
* or <code>null</code> to store in <code>request()</code> instead.
* @param value Bean value to store.
*
* @exception JspException Scope name is not recognized as a valid scope
*/
public static void setAttribute(
PageContext pageContext,
String name,
Object value,
String scope)
throws JspException {
if (scope == null)
pageContext.setAttribute(name, value, PageContext.REQUEST_SCOPE);
else if (scope.equalsIgnoreCase("page"))
pageContext.setAttribute(name, value, PageContext.PAGE_SCOPE);
else if (scope.equalsIgnoreCase("request"))
pageContext.setAttribute(name, value, PageContext.REQUEST_SCOPE);
else if (scope.equalsIgnoreCase("session"))
pageContext.setAttribute(name, value, PageContext.SESSION_SCOPE);
else if (scope.equalsIgnoreCase("application"))
pageContext.setAttribute(name, value, PageContext.APPLICATION_SCOPE);
else {
throw new JspException("Error - bad scope name '" + scope + "'");
}
}
/**
* Store bean in REQUEST_SCOPE context.
*
* @param pageContext Current pageContext.
* @param name Name of the bean.
* @param beanValue Bean value to store.
*
* @exception JspException Scope name is not recognized as a valid scope
*/
public static void setAttribute(PageContext pageContext, String name, Object beanValue)
throws JspException {
pageContext.setAttribute(name, beanValue, PageContext.REQUEST_SCOPE);
}
/**
* Save the specified exception as a request attribute for later use.
*
* @param pageContext The PageContext for the current page.
* @param exception The exception to be saved.
*/
public static void saveException(PageContext pageContext, Throwable exception) {
pageContext.setAttribute(Globals.EXCEPTION_KEY, exception, PageContext.REQUEST_SCOPE);
}
/**
* Get component definition by its name.
* @param name Definition name.
* @param pageContext The PageContext for the current page.
* @throws JspException -
*/
public static ComponentDefinition getComponentDefinition(String name, PageContext pageContext)
throws JspException {
try {
return TilesUtil.getDefinition(
name,
pageContext.getRequest(),
pageContext.getServletContext());
} catch (NoSuchDefinitionException ex) {
throw new JspException(
"Error : Can't get component definition for '"
+ name
+ "'. Check if this name exist in component definitions.",ex);
} catch (FactoryNotFoundException ex) { // factory not found.
throw new JspException(ex);
} catch (DefinitionsFactoryException ex) {
if (debug)
ex.printStackTrace();
// Save exception to be able to show it later
saveException(pageContext, ex);
throw new JspException(ex);
}
}
}