org.springframework.web.servlet.view.script.ScriptTemplateConfigurer Maven / Gradle / Ivy
/*
* Copyright 2002-2019 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
*
* https://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 java.util.function.Supplier;
import javax.script.Bindings;
import javax.script.ScriptEngine;
import org.springframework.lang.Nullable;
/**
* An implementation of Spring MVC's {@link ScriptTemplateConfig} for creating
* a {@code ScriptEngine} for use in a web application.
*
*
* // 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;
* }
*
*
* NOTE: 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 {
@Nullable
private ScriptEngine engine;
@Nullable
private Supplier engineSupplier;
@Nullable
private String engineName;
@Nullable
private Boolean sharedEngine;
@Nullable
private String[] scripts;
@Nullable
private String renderObject;
@Nullable
private String renderFunction;
@Nullable
private String contentType;
@Nullable
private Charset charset;
@Nullable
private String resourceLoaderPath;
/**
* Default constructor.
*/
public ScriptTemplateConfigurer() {
}
/**
* Create a new ScriptTemplateConfigurer using the given engine name.
*/
public ScriptTemplateConfigurer(String engineName) {
this.engineName = engineName;
}
/**
* Set the {@link ScriptEngine} to use by the view.
* If {@code renderFunction} is specified, the script engine must implement {@code Invocable}.
* You must define {@code engine} or {@code engineName}, not both.
* When the {@code sharedEngine} flag is set to {@code false}, you should not specify
* the script engine with this setter, but with {@link #setEngineName(String)}
* or {@link #setEngineSupplier(Supplier)} since it implies multiple lazy
* instantiations of the script engine.
* @see #setEngineName(String)
* @see #setEngineSupplier(Supplier)
*/
public void setEngine(@Nullable ScriptEngine engine) {
this.engine = engine;
}
@Override
@Nullable
public ScriptEngine getEngine() {
return this.engine;
}
/**
* Set the {@link ScriptEngine} supplier to use by the view, usually used with
* {@link #setSharedEngine(Boolean)} set to {@code false}.
* If {@code renderFunction} is specified, the script engine must implement {@code Invocable}.
* You must either define {@code engineSupplier}, {@code engine} or {@code engineName}.
* @since 5.2
* @see #setEngine(ScriptEngine)
* @see #setEngineName(String)
*/
public void setEngineSupplier(@Nullable Supplier engineSupplier) {
this.engineSupplier = engineSupplier;
}
@Override
@Nullable
public Supplier getEngineSupplier() {
return this.engineSupplier;
}
/**
* Set the engine name that will be used to instantiate the {@link ScriptEngine}.
* If {@code renderFunction} is specified, the script engine must implement {@code Invocable}.
* You must define {@code engine} or {@code engineName}, not both.
* @see #setEngine(ScriptEngine)
* @see #setEngineSupplier(Supplier)
*/
public void setEngineName(@Nullable String engineName) {
this.engineName = engineName;
}
@Override
@Nullable
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.
* When this flag is set to {@code false}, the script engine must be specified using
* {@link #setEngineName(String)} or {@link #setEngineSupplier(Supplier)}.
* Using {@link #setEngine(ScriptEngine)} is not possible because multiple instances
* of the script engine need to be created lazily (one per thread).
* @see THREADING ScriptEngine parameter
*/
public void setSharedEngine(@Nullable Boolean sharedEngine) {
this.sharedEngine = sharedEngine;
}
@Override
@Nullable
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.
*
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 WebJars
*/
public void setScripts(@Nullable String... scriptNames) {
this.scripts = scriptNames;
}
@Override
@Nullable
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(@Nullable String renderObject) {
this.renderObject = renderObject;
}
@Override
@Nullable
public String getRenderObject() {
return this.renderObject;
}
/**
* Set the render function name (optional). If not specified, the script templates
* will be evaluated with {@link ScriptEngine#eval(String, Bindings)}.
*
This function will be called with the following parameters:
*
* - {@code String template}: the template content
* - {@code Map model}: the view model
* - {@code RenderingContext context}: the rendering context (since 5.0)
*
* @see RenderingContext
*/
public void setRenderFunction(@Nullable String renderFunction) {
this.renderFunction = renderFunction;
}
@Override
@Nullable
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(@Nullable String contentType) {
this.contentType = contentType;
}
/**
* Return the content type to use for the response.
* @since 4.2.1
*/
@Override
@Nullable
public String getContentType() {
return this.contentType;
}
/**
* Set the charset used to read script and template files.
* ({@code UTF-8} by default).
*/
public void setCharset(@Nullable Charset charset) {
this.charset = charset;
}
@Override
@Nullable
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.
* Default is "classpath:".
*/
public void setResourceLoaderPath(@Nullable String resourceLoaderPath) {
this.resourceLoaderPath = resourceLoaderPath;
}
@Override
@Nullable
public String getResourceLoaderPath() {
return this.resourceLoaderPath;
}
}