/*
* Copyright 2002-2010 the original author or authors.
*
* Licensed 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.springframework.web.servlet.view.velocity;
import java.lang.reflect.Method;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.context.Context;
import org.apache.velocity.tools.view.ToolboxManager;
import org.apache.velocity.tools.view.context.ChainedContext;
import org.apache.velocity.tools.view.servlet.ServletToolboxManager;
import org.springframework.util.ClassUtils;
import org.springframework.util.ReflectionUtils;
/**
* {@link VelocityView} subclass which adds support for Velocity Tools toolboxes
* and Velocity Tools ViewTool callbacks / Velocity Tools 1.3 init methods.
*
* <p>Specify a "toolboxConfigLocation", for example "/WEB-INF/toolbox.xml",
* to automatically load a Velocity Tools toolbox definition file and expose
* all defined tools in the specified scopes. If no config location is
* specified, no toolbox will be loaded and exposed.
*
* <p>This view will always create a special Velocity context, namely an
* instance of the ChainedContext class which is part of the view package
* of Velocity tools. This allows to use tools from the view package of
* Velocity Tools, like LinkTool, which need to be initialized with a special
* context that implements the ViewContext interface (i.e. a ChainedContext).
*
* <p>This view also checks tools that are specified as "toolAttributes":
* If they implement the ViewTool interface, they will get initialized with
* the Velocity context. This allows tools from the view package of Velocity
* Tools, such as LinkTool, to be defined as
* {@link #setToolAttributes "toolAttributes"} on a VelocityToolboxView,
* instead of in a separate toolbox XML file.
*
* <p>This is a separate class mainly to avoid a required dependency on
* the view package of Velocity Tools in {@link VelocityView} itself.
* As of Spring 3.0, this class requires Velocity Tools 1.3 or higher.
*
* @author Juergen Hoeller
* @since 1.1.3
* @see #setToolboxConfigLocation
* @see #initTool
* @see org.apache.velocity.tools.view.context.ViewContext
* @see org.apache.velocity.tools.view.context.ChainedContext
*/
public class VelocityToolboxView extends VelocityView {
private String toolboxConfigLocation;
/**
* Set a Velocity Toolbox config location, for example "/WEB-INF/toolbox.xml",
* to automatically load a Velocity Tools toolbox definition file and expose
* all defined tools in the specified scopes. If no config location is
* specified, no toolbox will be loaded and exposed.
* <p>The specfied location string needs to refer to a ServletContext
* resource, as expected by ServletToolboxManager which is part of
* the view package of Velocity Tools.
* @see org.apache.velocity.tools.view.servlet.ServletToolboxManager#getInstance
*/
public void setToolboxConfigLocation(String toolboxConfigLocation) {
this.toolboxConfigLocation = toolboxConfigLocation;
}
/**
* Return the Velocity Toolbox config location, if any.
*/
protected String getToolboxConfigLocation() {
return this.toolboxConfigLocation;
}
/**
* Overridden to create a ChainedContext, which is part of the view package
* of Velocity Tools, as special context. ChainedContext is needed for
* initialization of ViewTool instances.
* @see #initTool
*/
@Override
protected Context createVelocityContext(
Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) throws Exception {
// Create a ChainedContext instance.
ChainedContext velocityContext = new ChainedContext(
new VelocityContext(model), getVelocityEngine(), request, response, getServletContext());
// Load a Velocity Tools toolbox, if necessary.
if (getToolboxConfigLocation() != null) {
ToolboxManager toolboxManager = ServletToolboxManager.getInstance(
getServletContext(), getToolboxConfigLocation());
Map toolboxContext = toolboxManager.getToolbox(velocityContext);
velocityContext.setToolbox(toolboxContext);
}
return velocityContext;
}
/**
* Overridden to check for the ViewContext interface which is part of the
* view package of Velocity Tools. This requires a special Velocity context,
* like ChainedContext as set up by {@link #createVelocityContext} in this class.
*/
@Override
protected void initTool(Object tool, Context velocityContext) throws Exception {
// Velocity Tools 1.3: a class-level "init(Object)" method.
Method initMethod = ClassUtils.getMethodIfAvailable(tool.getClass(), "init", Object.class);
if (initMethod != null) {
ReflectionUtils.invokeMethod(initMethod, tool, velocityContext);
}
}
}