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package com.sun.faces.config.configprovider;

import java.net.URISyntaxException;
import java.net.URL;
import java.util.Collection;
import java.util.List;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Set;
import java.io.IOException;

import javax.servlet.ServletContext;
import javax.faces.FacesException;

import com.sun.faces.facelets.util.Classpath;
import com.sun.faces.util.Util;
import com.sun.faces.spi.ConfigurationResourceProvider;
import java.net.URI;

/**
 *
 */
public class MetaInfFaceletTaglibraryConfigProvider implements
      ConfigurationResourceProvider {

    private static final String SUFFIX = ".taglib.xml";
    private static final String WEB_INF_CLASSES =
          "/WEB-INF/classes/META-INF";

    /**
     * Array of taglib.xml files included with Facelets 1.1.x.  If they are
     * on the classpath, we don't want to process them.
     */
    private static final String[] FACELET_CONFIG_FILES = {
        "META-INF/jsf-core.taglib.xml",
        "META-INF/jsf-html.taglib.xml",
        "META-INF/jsf-ui.taglib.xml",
        "META-INF/jstl-core.taglib.xml",
        "META-INF/jstl-fn.taglib.xml"
    };


    // -------------------------------------------- Methods from ConfigProcessor


    public Collection<URI> getResources(ServletContext context) {

        try {
            URL[] urls = Classpath.search(Util.getCurrentLoader(this),
                                          "META-INF/",
                                          SUFFIX);
            // perform some 'correctness' checking.  If the user has
            // removed the FaceletViewHandler from their configuration,
            // but has left the jsf-facelets.jar in the classpath, we
            // need to ignore the default configuration resouces from
            // that JAR.
            List<URI> urlsList = pruneURLs(urls);

            // special case for finding taglib files in WEB-INF/classes/META-INF
            Set paths = context.getResourcePaths(WEB_INF_CLASSES);
            if (paths != null) {
                for (Object path : paths) {
                    String p = path.toString();
                    if (p.endsWith(".taglib.xml")) {
                        try {
                            urlsList.add(new URI(context.getResource(p).toExternalForm()));
                        } catch (URISyntaxException ex) {
                            throw new FacesException(ex);
                        }
                    }
                }
            }
            return urlsList;
        } catch (IOException ioe) {
            throw new FacesException("Error searching classpath from facelet-taglib documents", ioe);
        }

    }


    // --------------------------------------------------------- Private Methods


    private List<URI> pruneURLs(URL[] urls) {

        List<URI> ret = null;
        if (urls != null && urls.length > 0) {
            for (URL url : urls) {
                String u = url.toString();
                boolean found = false;
                for (String excludeName : FACELET_CONFIG_FILES) {
                    if (u.contains(excludeName)) {
                        found = true;
                        break;
                    }
                }
                if (!found) {
                    if (ret == null) {
                        ret = new ArrayList<URI>();
                    }
                    try {
                        String urlString = url.toExternalForm();
                        urlString = urlString.replaceAll(" ", "%20");
                        ret.add(new URI(urlString));
                    } catch (URISyntaxException ex) {
                        throw new FacesException(ex);
                    }
                }
            }
        }

        if (ret == null) {
            ret = Collections.emptyList();
        }
        return ret;

    }


}