/*
* Copyright 2002-2015 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.script;
import java.nio.charset.Charset;
import javax.script.ScriptEngine;
/**
* An implementation of Spring MVC's {@link ScriptTemplateConfig} for creating
* a {@code ScriptEngine} for use in a web application.
*
* <pre class="code">
*
* // Add the following to an @Configuration class
* @Bean
* public ScriptTemplateConfigurer mustacheConfigurer() {
* ScriptTemplateConfigurer configurer = new ScriptTemplateConfigurer();
* configurer.setEngineName("nashorn");
* configurer.setScripts("mustache.js");
* configurer.setRenderObject("Mustache");
* configurer.setRenderFunction("render");
* return configurer;
* }
* </pre>
*
* <p><b>NOTE:</b> It is possible to use non thread-safe script engines with
* templating libraries not designed for concurrency, like Handlebars or React running on
* Nashorn, by setting the {@link #setSharedEngine sharedEngine} property to {@code false}.
*
* @author Sebastien Deleuze
* @since 4.2
* @see ScriptTemplateView
*/
public class ScriptTemplateConfigurer implements ScriptTemplateConfig {
private ScriptEngine engine;
private String engineName;
private Boolean sharedEngine;
private String[] scripts;
private String renderObject;
private String renderFunction;
private String contentType;
private Charset charset;
private String resourceLoaderPath;
/**
* Set the {@link ScriptEngine} to use by the view.
* The script engine must implement {@code Invocable}.
* You must define {@code engine} or {@code engineName}, not both.
* <p>When the {@code sharedEngine} flag is set to {@code false}, you should not specify
* the script engine with this setter, but with the {@link #setEngineName(String)}
* one (since it implies multiple lazy instantiations of the script engine).
* @see #setEngineName(String)
*/
public void setEngine(ScriptEngine engine) {
this.engine = engine;
}
@Override
public ScriptEngine getEngine() {
return this.engine;
}
/**
* Set the engine name that will be used to instantiate the {@link ScriptEngine}.
* The script engine must implement {@code Invocable}.
* You must define {@code engine} or {@code engineName}, not both.
* @see #setEngine(ScriptEngine)
*/
public void setEngineName(String engineName) {
this.engineName = engineName;
}
@Override
public String getEngineName() {
return this.engineName;
}
/**
* When set to {@code false}, use thread-local {@link ScriptEngine} instances instead
* of one single shared instance. This flag should be set to {@code false} for those
* using non thread-safe script engines with templating libraries not designed for
* concurrency, like Handlebars or React running on Nashorn for example.
* In this case, Java 8u60 or greater is required due to
* <a href="https://bugs.openjdk.java.net/browse/JDK-8076099">this bug</a>.
* <p>When this flag is set to {@code false}, the script engine must be specified using
* {@link #setEngineName(String)}. Using {@link #setEngine(ScriptEngine)} is not
* possible because multiple instances of the script engine need to be created lazily
* (one per thread).
* @see <a href="http://docs.oracle.com/javase/8/docs/api/javax/script/ScriptEngineFactory.html#getParameter-java.lang.String-">THREADING ScriptEngine parameter<a/>
*/
public void setSharedEngine(Boolean sharedEngine) {
this.sharedEngine = sharedEngine;
}
@Override
public Boolean isSharedEngine() {
return this.sharedEngine;
}
/**
* Set the scripts to be loaded by the script engine (library or user provided).
* Since {@code resourceLoaderPath} default value is "classpath:", you can load easily
* any script available on the classpath.
* <p>For example, in order to use a JavaScript library available as a WebJars dependency
* and a custom "render.js" file, you should call
* {@code configurer.setScripts("/META-INF/resources/webjars/library/version/library.js",
* "com/myproject/script/render.js");}.
* @see #setResourceLoaderPath
* @see <a href="http://www.webjars.org">WebJars</a>
*/
public void setScripts(String... scriptNames) {
this.scripts = scriptNames;
}
@Override
public String[] getScripts() {
return this.scripts;
}
/**
* Set the object where the render function belongs (optional).
* For example, in order to call {@code Mustache.render()}, {@code renderObject}
* should be set to {@code "Mustache"} and {@code renderFunction} to {@code "render"}.
*/
public void setRenderObject(String renderObject) {
this.renderObject = renderObject;
}
@Override
public String getRenderObject() {
return this.renderObject;
}
/**
* Set the render function name (mandatory).
*
* <p>This function will be called with the following parameters:
* <ol>
* <li>{@code String template}: the template content</li>
* <li>{@code Map model}: the view model</li>
* <li>{@code String url}: the template url (since 4.2.2)</li>
* </ol>
*/
public void setRenderFunction(String renderFunction) {
this.renderFunction = renderFunction;
}
@Override
public String getRenderFunction() {
return this.renderFunction;
}
/**
* Set the content type to use for the response.
* ({@code text/html} by default).
* @since 4.2.1
*/
public void setContentType(String contentType) {
this.contentType = contentType;
}
/**
* Return the content type to use for the response.
* @since 4.2.1
*/
@Override
public String getContentType() {
return this.contentType;
}
/**
* Set the charset used to read script and template files.
* ({@code UTF-8} by default).
*/
public void setCharset(Charset charset) {
this.charset = charset;
}
@Override
public Charset getCharset() {
return this.charset;
}
/**
* Set the resource loader path(s) via a Spring resource location.
* Accepts multiple locations as a comma-separated list of paths.
* Standard URLs like "file:" and "classpath:" and pseudo URLs are supported
* as understood by Spring's {@link org.springframework.core.io.ResourceLoader}.
* Relative paths are allowed when running in an ApplicationContext.
* <p>Default is "classpath:".
*/
public void setResourceLoaderPath(String resourceLoaderPath) {
this.resourceLoaderPath = resourceLoaderPath;
}
@Override
public String getResourceLoaderPath() {
return this.resourceLoaderPath;
}
}