Java Resource File resourceExists(String s)

Description

Resource indicated by s can be a file name or a URL.

License

Open Source License

Parameter

Parameter	Description
s	a parameter

Declaration

public static boolean resourceExists(String s) 

Method Source Code

//package com.java2s;
/**/* w  w  w .j ava2 s .  co m*/
 * Copyright 2011 The ARIES Consortium (http://www.ariesonline.org) and
 * www.integratedmodelling.org. 
    
   This file is part of Thinklab.
    
   Thinklab is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published
   by the Free Software Foundation, either version 3 of the License,
   or (at your option) any later version.
    
   Thinklab is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.
    
   You should have received a copy of the GNU General Public License
   along with Thinklab.  If not, see <http://www.gnu.org/licenses/>.
 */

import java.io.File;

import java.io.IOException;

import java.net.MalformedURLException;

import java.net.URL;

public class Main {
    /**
     * Resource indicated by s can be a file name or a URL. Returns true if it's an
     * existing file or a URL that can be opened.
     * 
     * @param s
     * @return
     */
    public static boolean resourceExists(String s) {

        boolean ret = false;
        Object o = getSourceForResource(s);

        if (o != null) {

            if (o instanceof File) {
                ret = ((File) o).exists();
            } else if (o instanceof URL) {
                try {
                    ret = ((URL) o).openStream() != null;
                } catch (IOException e) {
                }
            }
        }
        return ret;
    }

    /**
     * Analyze the passed string and determine if it specifies an existing file resource
     * or URL. Return the appropriate object, that must be disambiguated using instanceof.
     * Meant to (inelegantly) solve problems coming from file name encodings in primitive
     * OS (e.g. Windows) that cannot be handled properly in file:// URLs. 
     * @return a valid URL, existing file, or null. No exceptions are thrown.
     */
    public static Object getSourceForResource(String s) {

        File f = new File(s);

        if (f.exists())
            return f;

        URL url = null;
        try {
            url = new URL(s);
        } catch (MalformedURLException e) {
        }

        if (url != null)
            return url;

        return null;
    }
}

Related

1. loadUTF8(String resource)
2. openInputStream(String resourceString, ClassLoader classLoader)
3. parseASX(String inputResource)
4. printUsage(ResourceBundle bundle)
5. put(String resource, Map headers, String data)
6. runtimeResourceLocation(String src)
7. sanitizeResource(String inputResource)
8. toFile(Class c, String resource)
9. toStream(String resource)