jnlpresource.java

编写程序

/*
 * @(#)JnlpResource.java	1.6 03/01/23
 * 
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package jnlp.sample.servlet;
import javax.servlet.ServletContext;
import java.net.URL;
import java.io.File;
import java.io.IOException;
import java.net.URLConnection;
import java.util.*;

/** 
 *  A JnlpResource encapsulate the information about a resource that is
 *  needed to process a JNLP Download Request.
 *
 *  The pattern matching arguments are: name, version-id, os, arch, and locale.
 *
 *  The outgoing arguments are:
 *     - path to resource in (WAR File)
 *     - product version-id (Version-id to return or null. Typically same as version-id above)
 *     - mime-type for content
 *     - lastModified date of WAR file resource
 * 
 */
public class JnlpResource {       
    private static final String JNLP_MIME_TYPE      = "application/x-java-jnlp-file";
    private static final String JAR_MIME_TYPE       = "application/x-java-archive";
    
    // Default extension for the JNLP file
    private static final String JNLP_EXTENSION      = ".jnlp";
    private static final String JAR_EXTENSION       = ".jar";    
    
    private static String _jnlpExtension = JNLP_EXTENSION;
    private static String _jarExtension = JAR_EXTENSION;
    
    public static void setDefaultExtensions(String jnlpExtension, String jarExtension) {
	if (jnlpExtension != null && jnlpExtension.length() > 0) {
	    if (!jnlpExtension.startsWith(".")) jnlpExtension = "." + jnlpExtension;
	    _jnlpExtension = jnlpExtension;	
	}
	if (jarExtension != null && jarExtension.length() > 0) {
	    if (!jarExtension .startsWith(".")) jarExtension  = "." + jarExtension ;
	    _jarExtension = jarExtension;	
	}
    }   
    
    /* Pattern matching arguments */
    private String _name;	  // Name of resource with path (this is the same as path for non-version based)
    private String _versionId;    // Version-id for resource, or null if none
    private String[] _osList;     // List of OSes for which resource should be returned
    private String[] _archList;   // List of architectures for which the resource should be returned
    private String[] _localeList; // List of locales for which the resource should be returned
    /* Information used for reply */
    private String _path;            // Path to resource in WAR file (unique)
    private URL    _resource;        // URL to resource in WAR file (unique - same as above really)
    private long   _lastModified;    // Last modified in WAR file
    private String _mimeType;        // Mime-type for resource
    private String _returnVersionId; // Version Id to return
    
    public JnlpResource(ServletContext context, String path) { 
	this(context, null, null, null, null, null, path, null); 
    }	
    
    public JnlpResource(ServletContext context, 
			String name, 
			String versionId, 
			String[] osList, 
			String[] archList, 
			String[] localeList,
			String path,
			String returnVersionId) {	
	// Matching arguments
	_name = name;
	_versionId = versionId;	
	_osList = osList;
	_archList = archList;
	_localeList = localeList;
	// Path arguments
	_path = path.trim();
	_returnVersionId = returnVersionId;
	
	/* Check for existance and get last modified timestamp */
	try {
	    _resource = context.getResource(path);	
	    if (_resource != null) {
		_mimeType = getMimeType(context, path);
		// Get last modified time
		URLConnection conn = _resource.openConnection();	
		_lastModified = conn.getLastModified();
		if (_lastModified == 0) {
		    // Arguably a bug in the JRE will not set the lastModified for file URLs, and
		    // always return 0. This is a workaround for that problem.
		    String filepath = context.getRealPath(path); 		
		    if (filepath != null) {
			File f = new File(filepath);	    
			if (f.exists()) {
			    _lastModified = f.lastModified();
			} else {
			    _resource = null;
			}
		    }
		}			
	    }
	} catch(IOException ioe) {
	    _resource = null;
	}				    			    
    }    
    
    /* Get resource specific attributes */
    public String getPath() { return _path; }
    public URL getResource() { return _resource; }             
    public String getMimeType() { return _mimeType; }    
    public long getLastModified() { return _lastModified; }    
    public boolean exists() { return _resource != null; }    
    public boolean isJnlpFile() { return _path.endsWith(_jnlpExtension); }
    public boolean isJarFile() { return _path.endsWith(_jarExtension); }
    
    /* Get JNLP version specific attributes */
    public String getName() { return _name; }	            
    public String getVersionId() { return _versionId; }	            
    public String[] getOSList()  { return _osList; }
    public String[] getArchList()  { return _archList; }
    public String[] getLocaleList()  { return _localeList; }
    public String   getReturnVersionId() { return _returnVersionId; }

    private String getMimeType(ServletContext context, String path) {	
	String mimeType = context.getMimeType(path);
	if (mimeType != null) return mimeType;	
	if (path.endsWith(_jnlpExtension)) return JNLP_MIME_TYPE;
	if (path.endsWith(_jarExtension)) return JAR_MIME_TYPE;
	return "application/unknown";
    }        
    
    /** Print info about an entry */
    public String toString() { 
	return "JnlpResource[WAR Path: " + _path + 
	    showEntry(" versionId=",_versionId) +
	    showEntry(" name=", _name) +
	    " lastModified=" + new Date(_lastModified) +
	    showEntry(" osList=", _osList) +
	    showEntry(" archList=", _archList) +
	    showEntry(" localeList=", _localeList) + "]" +
	    showEntry(" returnVersionId=", _returnVersionId) + "]";
	
    }
    
    private String showEntry(String msg, String value) {
	if (value == null) return "";
	return msg + value;		
    }
    
    private String showEntry(String msg, String[] value) {
	if (value == null) return "";
	return msg + java.util.Arrays.asList(value).toString();	
    }        
}