zkoss/zk

/* ThemeProperties.java

{{IS_NOTE
    Purpose:
        
    Description:
        
    History:
        Jul 31, 2012 4:36:37 PM , Created by jumperchen
}}IS_NOTE

Copyright (C) 2012 Potix Corporation. All Rights Reserved.

{{IS_RIGHT
}}IS_RIGHT
*/
package org.zkoss.web.fn;

import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletContext;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;

import org.zkoss.lang.Strings;
import org.zkoss.util.Maps;
import org.zkoss.util.resource.Locators;
import org.zkoss.web.util.resource.ServletContextLocator;
import org.zkoss.xel.FunctionMapper;
import org.zkoss.xel.VariableResolver;
import org.zkoss.xel.XelContext;
import org.zkoss.xel.taglib.Taglib;
import org.zkoss.xel.taglib.Taglibs;
import org.zkoss.xel.util.SimpleResolver;
import org.zkoss.xel.util.SimpleXelContext;
import org.zkoss.xel.zel.ELFactory;

/**
 * A utility theme properties loader
 * @author simonpai
 * @author jumperchen
 * @since 6.5.0
 */
public class ThemeProperties {
    private ThemeProperties() {
    }

    private static final ELFactory _ELF = new ELFactory();
    private static final String THEME_FN_URL = "http://www.zkoss.org/dsp/web/theme";
    private static final String CORE_FN_URL = "http://www.zkoss.org/dsp/web/core";

    /**
     * Loads a properties file and apply them into the request scope
     */
    public static boolean loadProperties(ServletRequest req, String bundleName) {
        final Locators.StreamLocation loc = Locators.locateAsStream(bundleName, null, Locators.getDefault());
        if (loc != null)
            return loadProperties(req, loc.stream);
        else {
            // add ability to load theme properties from a folder
            // @since 6.5.2
            String root = ((HttpServletRequest) req).getContextPath();
            ServletContext context = ServletFns.getCurrentServletContext();
            bundleName = bundleName.replace(root, "");

            return loadProperties(req, new ServletContextLocator(context).getResourceAsStream(bundleName));
        }
    }

    /**
     * Loads a properties file and apply them into the request scope
     */
    public static boolean loadProperties(ServletRequest req, InputStream in) {
        Map<String, Object> pmap = new LinkedHashMap<String, Object>(); // preserve order
        try {
            Maps.load(pmap, in);
            return loadProperties(req, pmap);
        } catch (IOException e) {
            return false;
        }
    }
    
    private static boolean loadProperties(ServletRequest req, Map<String, Object> pmap) {
        Map<String, Object> map = getPropertyMap(req, "_theme");
        XelContext ctx = buildXelContext(map);
        for (Map.Entry<String, Object> e : pmap.entrySet()) {
            Object objv = e.getValue();
            if (objv == null)
                continue;
            String v = objv.toString();
            if (Strings.isBlank(v))
                continue;
            Object w = v.contains("${") ? _ELF.evaluate(ctx, v, Object.class) : v;
            
            map.put(e.getKey(), w);
            req.setAttribute(e.getKey(), w);
            
        }
        return true;
    }

    @SuppressWarnings("unchecked")
    public static Map<String, Object> getPropertyMap(ServletRequest req, String key) {
        Object obj = req.getAttribute(key);
        if (obj == null) {
            Map<String, Object> m = new HashMap<String, Object>(200);
            req.setAttribute(key, m);
            Enumeration names = req.getAttributeNames();
            while (names.hasMoreElements()) {
                String name = (String) names.nextElement();
                m.put(name, req.getAttribute(name));
            }
            return m;
        }
        if (obj instanceof Map<?, ?>)
            return (Map<String, Object>) obj;
        throw new IllegalStateException("Root node is not a Map: " + key);
    }

    private static XelContext buildXelContext(Map<String, Object> map) {
        List<Taglib> libs = Arrays.asList(new Taglib("t", THEME_FN_URL), new Taglib("c", CORE_FN_URL));
        FunctionMapper mapper = Taglibs.getFunctionMapper(libs, Locators.getDefault());
        VariableResolver resolver = new SimpleResolver(map);
        return new SimpleXelContext(resolver, mapper);
    }
}