AbstractURLContext.java

/*
 * Copyright (C) The Spice Group. All rights reserved.
 *
 * This software is published under the terms of the Spice
 * Software License version 1.1, a copy of which has been included
 * with this distribution in the LICENSE.txt file.
 */
package org.realityforge.spice.jndikit;

import java.util.Hashtable;
import javax.naming.Binding;
import javax.naming.CompositeName;
import javax.naming.Context;
import javax.naming.InvalidNameException;
import javax.naming.Name;
import javax.naming.NameClassPair;
import javax.naming.NameParser;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.spi.ResolveResult;

/**
 * Abstract JNDI Context that can be inherited from to provide a particular type of Context.
 */
public abstract class AbstractURLContext
  extends AbstractContext
  implements NameParser
{
  private final String m_scheme;

  public AbstractURLContext( final String scheme, final Hashtable<String, Object> environment )
  {
    super( environment );
    m_scheme = scheme;
  }

  /**
   * {@inheritDoc}
   */
  public Name parse( final String name )
    throws NamingException
  {
    return ( new CompositeName().add( name ) );
  }

  /**
   * {@inheritDoc}
   */
  protected NameParser getNameParser()
    throws NamingException
  {
    return this;
  }

  /**
   * {@inheritDoc}
   */
  protected void bind( final Name name, final Object object, final boolean rebind )
    throws NamingException
  {
    final ResolveResult resolveResult = getBaseURLContext( name, getRawEnvironment() );
    final Context context = (Context) resolveResult.getResolvedObj();

    try
    {
      if ( rebind )
      {
        context.rebind( resolveResult.getRemainingName(), object );
      }
      else
      {
        context.bind( resolveResult.getRemainingName(), object );
      }
    }
    finally
    {
      context.close();
    }
  }

  /**
   * {@inheritDoc}
   */
  public Context createSubcontext( final Name name )
    throws NamingException
  {
    final ResolveResult resolveResult = getBaseURLContext( name, getRawEnvironment() );
    final Context context = (Context) resolveResult.getResolvedObj();

    try
    {
      return context.createSubcontext( resolveResult.getRemainingName() );
    }
    finally
    {
      context.close();
    }
  }

  /**
   * {@inheritDoc}
   */
  public void destroySubcontext( final Name name )
    throws NamingException
  {
    final ResolveResult resolveResult = getBaseURLContext( name, getRawEnvironment() );
    final Context context = (Context) resolveResult.getResolvedObj();
    try
    {
      context.destroySubcontext( resolveResult.getRemainingName() );
    }
    finally
    {
      context.close();
    }
  }

  /**
   * {@inheritDoc}
   */
  public String getNameInNamespace()
    throws NamingException
  {
    return "";
  }

  /**
   * {@inheritDoc}
   */
  public NamingEnumeration<NameClassPair> list( final Name name )
    throws NamingException
  {
    final ResolveResult resolveResult = getBaseURLContext( name, getRawEnvironment() );
    final Context context = (Context) resolveResult.getResolvedObj();

    try
    {
      return context.list( resolveResult.getRemainingName() );
    }
    finally
    {
      context.close();
    }
  }

  /**
   * {@inheritDoc}
   */
  public NamingEnumeration<Binding> listBindings( final Name name )
    throws NamingException
  {
    final ResolveResult resolveResult = getBaseURLContext( name, getRawEnvironment() );
    final Context context = (Context) resolveResult.getResolvedObj();

    try
    {
      return context.listBindings( resolveResult.getRemainingName() );
    }
    finally
    {
      context.close();
    }
  }

  /**
   * {@inheritDoc}
   */
  public Object lookup( final Name name )
    throws NamingException
  {
    final ResolveResult resolveResult = getBaseURLContext( name, getRawEnvironment() );
    final Context context = (Context) resolveResult.getResolvedObj();

    try
    {
      return context.lookup( resolveResult.getRemainingName() );
    }
    finally
    {
      context.close();
    }
  }

  /**
   * {@inheritDoc}
   */
  public void unbind( final Name name )
    throws NamingException
  {
    final ResolveResult resolveResult = getBaseURLContext( name, getRawEnvironment() );
    final Context context = (Context) resolveResult.getResolvedObj();

    try
    {
      context.unbind( resolveResult.getRemainingName() );
    }
    finally
    {
      context.close();
    }
  }

  protected ResolveResult getBaseURLContext( final Name name, final Hashtable environment )
    throws NamingException
  {
    if ( name.isEmpty() )
    {
      throw new InvalidNameException( "Unable to locate URLContext will empty name" );
    }

    final String nameString = name.get( 0 ).toString();
    int index = nameString.indexOf( ':' );

    if ( -1 == index )
    {
      final String explanation = "Unable to build URLContext as it does not specify scheme";
      throw new InvalidNameException( explanation );
    }

    final String scheme = nameString.substring( 0, index );
    final int end = getEndIndexOfURLPart( nameString, index + 1 );
    final String urlPart = nameString.substring( index + 1, end );
    final String namePart = nameString.substring( end );

    if ( !m_scheme.equals( scheme ) )
    {
      final String explanation = "Bad Scheme use to build URLContext (" + scheme + "). " + "Expected " + m_scheme;
      throw new InvalidNameException( explanation );
    }

    final Context context = newContext( urlPart );

    return new ResolveResult( context, new CompositeName( namePart ) );
  }

  /**
   * Find end index of url part in string.
   * Default implementation looks for
   * //.../[name-part]
   * ///[name-part]
   * //... (no name part)
   * [name-part]
   *
   * @param name  the name
   * @param index the index where "scheme:" ends
   * @return the index where url ends
   * @throws NamingException if an error occurs
   */
  protected int getEndIndexOfURLPart( final String name, final int index )
    throws NamingException
  {
    int result = 0;

    //does it start with //
    if ( name.startsWith( "//", index ) )
    {
      //does it have .../  following ???
      int end = name.indexOf( "/", index + 2 );

      if ( -1 != end )
      {
        result = end;
      }
      else
      {
        result = name.length();
      }
    }

    return result;
  }

  /**
   * Return a new instance of the base context for a URL.
   * This must be implemented in particular URLContext.
   *
   * @param urlPart the part of url string not including "scheme:"
   * @return a base URLContext for urlPart
   * @throws javax.naming.NamingException if an error occurs
   */
  protected abstract Context newContext( String urlPart )
    throws NamingException;
}