SHRINKWRAP-112 - Create a Unified Importer API

[aslak]

We continue the discussion from [SHRINKWRAP-112|https://jira.jboss.org/jira/browse/SHRINKWRAP-112]

This is the current unified API description.
{code}
package org.jboss.shrinkwrap.api.importer;

import java.io.File;
import java.net.URL;

import org.jboss.shrinkwrap.api.Assignable;

/**
 * A Unified Import API to handle delegation to the appropriate importer.
 * ie: {@link ZipImporter} or {@link ExplodedImporter} 
 *
 * @author <a href="mailto:[e-mail]">Aslak Knutsen</a>
 * @version $Revision: $
 */
public interface Import extends Assignable
{
   //-------------------------------------------------------------------------------------||
   // Contracts --------------------------------------------------------------------------||
   //-------------------------------------------------------------------------------------||
   /**
    * Imports this path.
    * 
    * Overloads {@link #from(File)}.
    * 
    * @param path
    * @return
    * @throws ArchiveImportException
    */
   Import from(String path) throws ArchiveImportException;
   
   /**
    * Imports the resource at the given {@link File}.
    * 
    * Both files and directories are supported.
    * 
    * @param file
    * @return
    * @throws ArchiveImportException
    */
   Import from(File file) throws ArchiveImportException;
   
   /**
    * Imports the resource at the given {@link URL}.
    * 
    * Overloads {@link #from(File)} if this is a file:// {@link URL}.
    * 
    * @param url
    * @return
    * @throws ArchiveImportException
    */
   Import from(URL url) throws ArchiveImportException;
}
{code}
[Current impl|http://shrinkwrap.pastebin.com/m58f16a3a] works in the following way:
* from(String)
** from(new File(String))
* from(File)
** if File.isFile -> (should delegate to a lookup of a supported importer(based on extension?)) -> ZipImporter
** if File.isDirectory -> ExplodedImporter
* from(URL)
** if URL.getProtocol == file:// -> from(new File(url))
** if URL.getName -> (should delegate to a lookup of a supported importer(based on extension?)) -> ZipImporter
The big questions are:
* what should from(String) do?
* any missing common objects we should support in from(?)?
** InputStream?
 

[alrubinger]

Instead of overloading, why not be clear in the method name?

fromUrl(URL)

fromUrl(String)

fromFile(File)

fromFile(String)

...etc

S,

ALR

[alrubinger]

To your second question; yep, we should allow importing from every type we export to, such that roundtrips are always possible.