CORBA/NamingService/NameTransformer.java

/* NameTransformer.java --
   Copyright (C) 2005 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath 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 2, or (at your option)
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General Public License for more details.

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02110-1301 USA.

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making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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package gnu.CORBA.NamingService;

import org.omg.CORBA.IntHolder;
import org.omg.CosNaming.NameComponent;
import org.omg.CosNaming.NamingContextPackage.InvalidName;

import java.util.ArrayList;
import java.util.StringTokenizer;

/**
 * This class converts between string and array representations of the
 * multi component object names.
 *
 * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org)
 */
public class NameTransformer
{
  /**
   * A string, indicating the escape character.
   */
  public static final String ESCAPE = "\\";

  /**
   * Convert the string name representation into the array name
   * representation. See {@link #toString(NameComponent)} for the
   * description of this format.
   *
   * @param name the string form of the name.
   *
   * @return the array form of the name.
   *
   * @throws InvalidName if the name cannot be parsed.
   */
  public NameComponent[] toName(String a_name)
                         throws InvalidName
  {
    ArrayList components = new ArrayList();
    StringTokenizer st = new StringTokenizer(a_name, "./\\", true);

    String id;
    String kind;
    String next;

    // Create the buffer array, reserving the last element for null.
    String[] n = new String[ st.countTokens() + 1 ];

    int pp = 0;
    while (st.hasMoreTokens())
      n [ pp++ ] = st.nextToken();

    IntHolder p = new IntHolder();

    NameComponent node = readNode(p, n);

    while (node != null)
      {
        components.add(node);
        node = readNode(p, n);
      }

    NameComponent[] name = new NameComponent[ components.size() ];
    for (int i = 0; i < name.length; i++)
      {
        name [ i ] = (NameComponent) components.get(i);
      }

    NameValidator.check(name);

    return name;
  }

  /**
   * Converts the name into its string representation, as defined in
   * the specification CORBA naming service.
   *
   * A string representation for the name consists of the name components,
   * separated by a slash '/' character (for example, 'a/b/c'). If the
   * {@link NameComponent#kind} field is  not empty, it is given after
   * period ('.'), for example 'a.b/c.d/.' .
   * The period alone represents node where part where both
   * {@link NameComponent#kind} and {@link NameComponent#id} are empty strings.
   *
   * If slash or dot are part of the name, they are escaped by backslash ('\').
   * If the backslash itself is part of the name, it is doubled.
   *
   * @param a_name a name to convert.
   * @return a string representation.
   */
  public String toString(NameComponent[] a_name)
                  throws InvalidName
  {
    NameValidator.check(a_name);

    StringBuffer b = new StringBuffer();

    NameComponent n;

    for (int ni = 0; ni < a_name.length; ni++)
      {
        n = a_name [ ni ];
        appEscaping(b, n.id);
        if (n.kind.length() > 0)
          {
            b.append('.');
            appEscaping(b, n.kind);
          }

        if (ni < a_name.length - 1)
          b.append('/');
      }
    return b.toString();
  }

  /**
   * Append the contents of the string to this
   * string buffer, inserting the escape sequences, where required.
   *
   * @param b a buffer to append the contents to.
   * @param s a string to append.
   */
  private void appEscaping(StringBuffer b, String s)
  {
    char c;
    for (int i = 0; i < s.length(); i++)
      {
        c = s.charAt(i);
        switch (c)
          {
            case '.' :
            case '/' :
            case '\\' :
              b.append('\\');
              b.append(c);
              break;

            default :
              b.append(c);
              break;
          }
      }
  }

  /**
   * Assert the end of the current name component.
   */
  private void assertEndOfNode(IntHolder p, String[] t)
                        throws InvalidName
  {
    if (t [ p.value ] != null)
      if (!t [ p.value ].equals("/"))
        throw new InvalidName("End of node expected at token " + p.value);
  }

  /**
   * Read the named component node. After reading the current positon
   * advances to the beginning of the next node in an array.
   *
   * @param p the current position being wrapped inside the passed
   * IntHolder.
   *
   * @param t the text buffer.
   *
   * @return the created node.
   */
  private NameComponent readNode(IntHolder p, String[] t)
                          throws InvalidName
  {
    // End of stream has been reached.
    if (t [ p.value ] == null)
      return null;

    NameComponent n = new NameComponent();

    if (t [ p.value ].equals("."))
      {
        // The 'id' is missing, but the 'kind' may follow.
        n.id = "";
        p.value++;
        n.kind = readPart(p, t);
        assertEndOfNode(p, t);
        if (t [ p.value ] != null)
          p.value++;
      }
    else if (t [ p.value ].equals("/"))
      {
        // This is not allowed here and may happen only
        // on two subsequent slashes.
        throw new InvalidName("Unexpected '/' token " + p.value);
      }
    else
      {
        n.id = readPart(p, t);

        // If some chars follow the id.
        if (t [ p.value ] != null)
          {
            // Dot means that the kind part follows
            if (t [ p.value ].equals("."))
              {
                p.value++;
                n.kind = readPart(p, t);
                assertEndOfNode(p, t);
                if (t [ p.value ] != null)
                  p.value++;
              }

            // The next name component follows - advance to
            // the beginning of the next name component.
            else if (t [ p.value ].equals("/"))
              {
                n.kind = "";
                p.value++;
              }
            else
              throw new InvalidName("Unexpected '" + t [ p.value ] +
                                       "' at token " + p.value
                                      );
          }
        else

          // Id, and then end of sequence.
          n.kind = "";
      }

    return n;
  }

  /**
   * Read the name part (id or kind).
   *
   * @param p the current position. After reading, advances
   * to the beginning of the next name fragment.
   *
   * @param t the string buffer.
   *
   * @return the name part with resolved escape sequences.
   */
  private String readPart(IntHolder p, String[] t)
  {
    StringBuffer part = new StringBuffer();

    while (t [ p.value ] != null && !t [ p.value ].equals(".") &&
           !t [ p.value ].equals("/")
          )
      {
        if (t [ p.value ].equals(ESCAPE))
          {
            p.value++;
            part.append(t [ p.value ]);
          }
        else
          part.append(t [ p.value ]);

        p.value++;
      }

    return part.toString();
  }

  public static void main(String[] args)
  {
    NameComponent a = new NameComponent("a", "ak");
    NameComponent b = new NameComponent("b/z", "b.k");
    NameComponent c = new NameComponent("c", "");

    NameTransformer sn = new NameTransformer();

    try
      {
        String s = sn.toString(new NameComponent[] { a, b, c });
        System.out.println(s);

        //NameComponent[] k = toName("a.k/b.k2/c/d/.");
        //NameComponent[] k = toName("a.bc/.b/c.x");

        NameComponent[] k = sn.toName(s);
        System.out.println("ToString");

        for (int i = 0; i < k.length; i++)
          {
            System.out.println(k [ i ].id + ":" + k [ i ].kind);
          }
      }
    catch (InvalidName ex)
      {
        ex.printStackTrace();
      }
  }

}