D-Net

package eu.dnetlib.springutils.stringtemplate;

import java.util.Locale;

import org.antlr.stringtemplate.StringTemplateGroup;

import org.springframework.beans.factory.BeanFactoryUtils;

import org.springframework.beans.factory.NoSuchBeanDefinitionException;

import org.springframework.context.ApplicationContextException;

import org.springframework.web.servlet.view.AbstractUrlBasedView;

import org.springframework.web.servlet.view.UrlBasedViewResolver;

/**

 * Spring MVC view resolver based on string templates. You can parameterize this resolver with a java package name under

 * the templates will be searched.

 * 

 * <p>

 * requires a StringTemplateGroup bean

 * </p>

 * 

 * <p>

 * This code is based to a public domain example taken from <a

 * href="http://jira.springframework.org/browse/SPR-3266">here</a>

 * </p>

 * 

 * @author marko

 * @author Brian Lewis

 * 

 */

public class StringTemplateViewResolver extends UrlBasedViewResolver {

	/**

	 * template group.

	 */

	private StringTemplateGroup templateGroup;

	public void setTemplateGroup(final StringTemplateGroup value) {

		templateGroup = value;

	}

	public StringTemplateGroup getTemplateGroup() {

		return templateGroup;

	}

	/**

	 * Sets default viewClass to <code>requiredViewClass</code>.

	 * 

	 * @see #setViewClass

	 * @see #requiredViewClass

	 */

	public StringTemplateViewResolver() {

		setViewClass(requiredViewClass()); // NOPMD

		// XXX bad but we have to make assumptions later

		setRequestContextAttribute("rc");

	}

	/**

	 * Requires StringTemplateView.

	 * 

	 * @see StringTemplateView

	 * @return view class

	 */

	@Override

	@SuppressWarnings({ "rawtypes", "unchecked" })

	protected Class requiredViewClass() {

		return StringTemplateView.class;

	}

	/**

	 * Invoked on startup. Looks for a single StringTemplateGroup bean to find the relevant StringTemplate for this

	 * factory.

	 */

	@Override

	protected void initApplicationContext() {

		super.initApplicationContext();

		if (getTemplateGroup() == null) {

			// No explicit StringTemplateGroup: try to autodetect one.

			setTemplateGroup(autodetectMyStringTemplateGroup());

		}

	}

	/**

	 * Autodetect a StringTemplateGroup via the ApplicationContext. Called if no explicit StringTemplateGroup has been

	 * specified.

	 * 

	 * @return the StringTemplateGroup to use for StringTemplateViews

	 * @see #getApplicationContext

	 * @see #setMyStringTemplateGroup

	 */

	protected StringTemplateGroup autodetectMyStringTemplateGroup() {

		try {

			final StringTemplateGroup group = (StringTemplateGroup) BeanFactoryUtils.beanOfTypeIncludingAncestors(getApplicationContext(),

					StringTemplateGroup.class, true, false);

			return group;

		} catch (NoSuchBeanDefinitionException ex) {

			throw new ApplicationContextException("Must define a single StringTemplateGroup bean in this web application context"

					+ " (may be inherited). StringTemplateGroup is the usual implementation." + " This bean may be given any name.", ex);

		}

	}

	/**

	 * {@inheritDoc}

	 * 

	 * @see org.springframework.web.servlet.view.UrlBasedViewResolver#buildView(java.lang.String)

	 */

	@Override

	protected AbstractUrlBasedView buildView(final String viewName) throws Exception { // NOPMD

		if (logger.isDebugEnabled())

			logger.debug("looking up by view name: '" + viewName + "' based in '" + getPrefix() + "'");

		final StringTemplateView view = (StringTemplateView) super.buildView(getPrefix() + viewName);

		view.setStringTemplate(templateGroup.getInstanceOf(getPrefix() + viewName));

		return view;

	}

	@Override

	protected boolean canHandle(String viewName, Locale locale) {

		if(viewName.startsWith("redirect:"))

			return true;

		try {

			templateGroup.getInstanceOf(getPrefix() + viewName);

		} catch (IllegalArgumentException e) {

			return false;

		}

		if (super.canHandle(viewName, locale))

			return true;

		return true;

	}

}