FreemarkerViewProcessor.java

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package com.sun.jersey.freemarker;

import com.sun.jersey.api.container.ContainerException;
import com.sun.jersey.api.core.ResourceConfig;
import com.sun.jersey.api.view.Viewable;
import com.sun.jersey.spi.template.ViewProcessor;
import freemarker.template.Configuration;
import freemarker.template.DefaultObjectWrapper;
import freemarker.template.Template;
import freemarker.template.TemplateException;

import javax.ws.rs.core.Context;
import javax.ws.rs.core.UriInfo;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;

/**
 * @author pavel.bucek@oracle.com
 */
public class FreemarkerViewProcessor implements ViewProcessor<String> {

    /**
     * Freemarker templates base path.
     *
     * Mandatory parameter, it has to be set if you plan to use freemarker
     * to generate your views.
     */
    public final static String FREEMARKER_TEMPLATES_BASE_PATH =
            "com.sun.jersey.freemarker.templateBasePath";

    private final Configuration configuration;
    private @Context UriInfo uriInfo;

    private String basePath;

    public FreemarkerViewProcessor(@Context ResourceConfig resourceConfig) {
        configuration = new Configuration();
        configuration.setObjectWrapper(new DefaultObjectWrapper());

        String path = (String)resourceConfig.getProperties().get(
                FREEMARKER_TEMPLATES_BASE_PATH);
        if (path == null)
            this.basePath = "";
        else if (path.charAt(0) == '/') {
            this.basePath = path;
        } else {
            this.basePath = "/" + path;
        }
    }

    @Override
    public String resolve(String path) {

        if (basePath != "")
            path = basePath + path;

        if (uriInfo.getMatchedResources().get(0).getClass().getResource(path) != null) {
            return path;
        }

        if (!path.endsWith(".ftl")) {
            path = path + ".ftl";
            if (uriInfo.getMatchedResources().get(0).getClass().getResource(path) != null) {
                return path;
            }
        }

        return null;
    }

    @Override
    public void writeTo(String resolvedPath, Viewable viewable, OutputStream out) throws IOException {
        // Commit the status and headers to the HttpServletResponse
        out.flush();

        configuration.setClassForTemplateLoading(uriInfo.getMatchedResources().get(0).getClass(), "/");
        final Template template = configuration.getTemplate(resolvedPath);

        try {
            template.process(viewable.getModel(), new OutputStreamWriter(out));
        } catch(TemplateException te) {
            throw new ContainerException(te);
        }
    }
}