freemarkerconfigurationfactory.java

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	public void setTemplateLoaderPaths(String[] templateLoaderPaths) {
		this.templateLoaderPaths = templateLoaderPaths;
	}

	/**
	 * Set the Spring ResourceLoader to use for loading FreeMarker template files.
	 * The default is DefaultResourceLoader. Will get overridden by the
	 * ApplicationContext if running in a context.
	 * @see org.springframework.core.io.DefaultResourceLoader
	 */
	public void setResourceLoader(ResourceLoader resourceLoader) {
		this.resourceLoader = resourceLoader;
	}

	/**
	 * Return the Spring ResourceLoader to use for loading FreeMarker template files.
	 */
	protected ResourceLoader getResourceLoader() {
		return resourceLoader;
	}

	/**
	 * Set whether to prefer file system access for template loading.
	 * File system access enables hot detection of template changes.
	 * <p>If this is enabled, FreeMarkerConfigurationFactory will try to resolve
	 * the specified "templateLoaderPath" as file system resource (which will work
	 * for expanded class path resources and ServletContext resources too).
	 * <p>Default is "true". Turn this off to always load via SpringTemplateLoader
	 * (i.e. as stream, without hot detection of template changes), which might
	 * be necessary if some of your templates reside in an expanded classes
	 * directory while others reside in jar files.
	 * @see #setTemplateLoaderPath
	 */
	public void setPreferFileSystemAccess(boolean preferFileSystemAccess) {
		this.preferFileSystemAccess = preferFileSystemAccess;
	}

	/**
	 * Return whether to prefer file system access for template loading.
	 */
	protected boolean isPreferFileSystemAccess() {
		return preferFileSystemAccess;
	}


	/**
	 * Prepare the FreeMarker Configuration and return it.
	 * @return the FreeMarker Configuration object
	 * @throws IOException if the config file wasn't found
	 * @throws TemplateException on FreeMarker initialization failure
	 */
	public Configuration createConfiguration() throws IOException, TemplateException {
		Configuration config = newConfiguration();
		Properties props = new Properties();

		// Load config file if specified.
		if (this.configLocation != null) {
			if (logger.isInfoEnabled()) {
				logger.info("Loading FreeMarker configuration from " + this.configLocation);
			}
			PropertiesLoaderUtils.fillProperties(props, this.configLocation);
		}

		// Merge local properties if specified.
		if (this.freemarkerSettings != null) {
			props.putAll(this.freemarkerSettings);
		}

		// FreeMarker will only accept known keys in its setSettings and
		// setAllSharedVariables methods.
		if (!props.isEmpty()) {
			config.setSettings(props);
		}

		if (!CollectionUtils.isEmpty(this.freemarkerVariables)) {
			config.setAllSharedVariables(new SimpleHash(this.freemarkerVariables));
		}

		if (this.defaultEncoding != null) {
			config.setDefaultEncoding(this.defaultEncoding);
		}

		// Register template loaders that are supposed to kick in early.
		if (this.preTemplateLoaders != null) {
			this.templateLoaders.addAll(this.preTemplateLoaders);
		}

		// Register default template loaders.
		if (this.templateLoaderPaths != null) {
			for (int i = 0; i < this.templateLoaderPaths.length; i++) {
				this.templateLoaders.add(getTemplateLoaderForPath(this.templateLoaderPaths[i]));
			}
		}
		postProcessTemplateLoaders(this.templateLoaders);

		// Register template loaders that are supposed to kick in late.
		if (this.postTemplateLoaders != null) {
			this.templateLoaders.addAll(this.postTemplateLoaders);
		}

		TemplateLoader loader = getAggregateTemplateLoader(this.templateLoaders);
		if (loader != null) {
			config.setTemplateLoader(loader);
		}

		postProcessConfiguration(config);
		return config;
	}

	/**
	 * Return a new Configuration object. Subclasses can override this for
	 * custom initialization, or for using a mock object for testing.
	 * <p>Called by <code>createConfiguration()</code>.
	 * @return the Configuration object
	 * @throws IOException if a config file wasn't found
	 * @throws TemplateException on FreeMarker initialization failure
	 * @see #createConfiguration()
	 */
	protected Configuration newConfiguration() throws IOException, TemplateException {
		return new Configuration();
	}

	/**
	 * Determine a FreeMarker TemplateLoader for the given path.
	 * <p>Default implementation creates either a FileTemplateLoader or
	 * a SpringTemplateLoader.
	 * @param templateLoaderPath the path to load templates from
	 * @return an appropriate TemplateLoader
	 * @see freemarker.cache.FileTemplateLoader
	 * @see SpringTemplateLoader
	 */
	protected TemplateLoader getTemplateLoaderForPath(String templateLoaderPath) {
		if (isPreferFileSystemAccess()) {
			// Try to load via the file system, fall back to SpringTemplateLoader
			// (for hot detection of template changes, if possible).
			try {
				Resource path = getResourceLoader().getResource(templateLoaderPath);
				File file = path.getFile();  // will fail if not resolvable in the file system
				if (logger.isDebugEnabled()) {
					logger.debug(
							"Template loader path [" + path + "] resolved to file path [" + file.getAbsolutePath() + "]");
				}
				return new FileTemplateLoader(file);
			}
			catch (IOException ex) {
				if (logger.isDebugEnabled()) {
					logger.debug("Cannot resolve template loader path [" + templateLoaderPath +
							"] to [java.io.File]: using SpringTemplateLoader as fallback", ex);
				}
				return new SpringTemplateLoader(getResourceLoader(), templateLoaderPath);
			}
		}
		else {
			// Always load via SpringTemplateLoader (without hot detection of template changes).
			logger.debug("File system access not preferred: using SpringTemplateLoader");
			return new SpringTemplateLoader(getResourceLoader(), templateLoaderPath);
		}
	}

	/**
	 * To be overridden by subclasses that want to to register custom
	 * TemplateLoader instances after this factory created its default
	 * template loaders.
	 * <p>Called by <code>createConfiguration()</code>. Note that specified
	 * "postTemplateLoaders" will be registered <i>after</i> any loaders
	 * registered by this callback; as a consequence, they are are <i>not</i>
	 * included in the given List.
	 * @param templateLoaders the current List of TemplateLoader instances,
	 * to be modified by a subclass
	 * @see #createConfiguration()
	 * @see #setPostTemplateLoaders
	 */
	protected void postProcessTemplateLoaders(List templateLoaders) {
	}

	/**
	 * Return a TemplateLoader based on the given TemplateLoader list.
	 * If more than one TemplateLoader has been registered, a FreeMarker
	 * MultiTemplateLoader needs to be created.
	 * @param templateLoaders the final List of TemplateLoader instances
	 * @return the aggregate TemplateLoader
	 */
	protected TemplateLoader getAggregateTemplateLoader(List templateLoaders) {
		int loaderCount = templateLoaders.size();
		switch (loaderCount) {
			case 0:
				logger.info("No FreeMarker TemplateLoaders specified");
				return null;
			case 1:
				return (TemplateLoader) templateLoaders.get(0);
			default:
				TemplateLoader[] loaders = (TemplateLoader[]) templateLoaders.toArray(new TemplateLoader[loaderCount]);
				return new MultiTemplateLoader(loaders);
		}
	}

	/**
	 * To be overridden by subclasses that want to to perform custom
	 * post-processing of the Configuration object after this factory
	 * performed its default initialization.
	 * <p>Called by <code>createConfiguration()</code>.
	 * @param config the current Configuration object
	 * @throws IOException if a config file wasn't found
	 * @throws TemplateException on FreeMarker initialization failure
	 * @see #createConfiguration()
	 */
	protected void postProcessConfiguration(Configuration config) throws IOException, TemplateException {
	}

}