org.apache.myfaces.shared_tomahawk.resource.ResourceLoader Maven / Gradle / Ivy

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JSF components and utilities that can be used with any JSF implementation. This library is based on the JSF1.1 version of Tomahawk, but with minor source code and build changes to take advantage of JSF2.1 features. A JSF2.1 implementation is required to use this version of the Tomahawk library.
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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.myfaces.shared_tomahawk.resource;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Comparator;

/**
 * Base class for resource loaders.  Resource loaders can lookup resources 
 * as URLs from arbitrary locations, including JAR files.
 * 
 * @author Leonardo Uribe (latest modification by $Author: lu4242 $)
 * @version $Revision: 1213371 $ $Date: 2011-12-12 14:12:00 -0500 (Mon, 12 Dec 2011) $
 */
public abstract class ResourceLoader
{
    
    public static final String VERSION_INVALID = "INVALID";
    
    private String _prefix;
    
    public ResourceLoader(String prefix)
    {
        _prefix = prefix;
    }

    public abstract String getResourceVersion(String path);

    /**
     * Return the max available version found (if exists) or
     * return null if no version available. 
     */
    public abstract String getLibraryVersion(String path);

    /**
     * Return the max available version found (if exists) or
     * return null if no version available. 
     */
    public abstract URL getResourceURL(ResourceMeta resourceMeta);

    public abstract InputStream getResourceInputStream(ResourceMeta resourceMeta);
    
    public abstract ResourceMeta createResourceMeta(String prefix, String libraryName, String libraryVersion,
            String resourceName, String resourceVersion);
    
    public abstract boolean libraryExists(String libraryName);
    
    public boolean resourceExists(ResourceMeta resourceMeta)
    {
        return (getResourceURL(resourceMeta) != null);
    }
    
    private Comparator _versionComparator = null;

    protected Comparator getVersionComparator()
    {
        if (_versionComparator == null)
        {
            _versionComparator = new VersionComparator();
        }
        return _versionComparator;
    }

    protected void setVersionComparator(Comparator versionComparator)
    {
        _versionComparator = versionComparator;
    }

    public class VersionComparator implements Comparator
    {

        public int compare(String s1, String s2)
        {
            int n1 = 0;
            int n2 = 0;
            String o1 = s1;
            String o2 = s2;

            boolean p1 = true;
            boolean p2 = true;

            while (n1 == n2 && (p1 || p2))
            {
                int i1 = o1.indexOf('_');
                int i2 = o2.indexOf('_');
                if (i1 < 0)
                {
                    if (o1.length() > 0)
                    {
                        p1 = false;
                        n1 = Integer.valueOf(o1);
                        o1 = "";
                    }
                    else
                    {
                        p1 = false;
                        n1 = 0;
                    }
                }
                else
                {
                    n1 = Integer.valueOf(o1.substring(0, i1));
                    o1 = o1.substring(i1 + 1);
                }
                if (i2 < 0)
                {
                    if (o2.length() > 0)
                    {
                        p2 = false;
                        n2 = Integer.valueOf(o2);
                        o2 = "";
                    }
                    else
                    {
                        p2 = false;
                        n2 = 0;
                    }
                }
                else
                {
                    n2 = Integer.valueOf(o2.substring(0, i2));
                    o2 = o2.substring(i2 + 1);
                }
            }

            if (n1 == n2)
            {
                return s1.length() - s2.length();
            }
            return n1 - n2;
        }
    }
    
    public String getPrefix()
    {
        return _prefix;
    }

    public void setPrefix(String prefix)
    {
        _prefix = prefix;
    }
}