package gnu.crypto.keyring;  // -*- c-basic-offset: 3 -*-

// ---------------------------------------------------------------------------
// $Id: Properties.java,v 1.4 2005/10/06 04:24:16 rsdio Exp $
//
// Copyright (C) 2003 Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto 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)
// any later version.
//
// GNU Crypto 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 this program; see the file COPYING.  If not, write to the
//
//    Free Software Foundation Inc.,
//    51 Franklin Street, Fifth Floor,
//    Boston, MA 02110-1301
//    USA
//
// Linking this library statically or dynamically with other modules is
// making a combined work based on this library.  Thus, the terms and
// conditions of the GNU General Public License cover the whole
// combination.
//
// 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 modules, and to copy and distribute the resulting
// executable under terms of your choice, provided that you also meet,
// for each linked independent module, the terms and conditions of the
// license of that module.  An independent module is a module which is
// not derived from or based on this library.  If you modify this
// library, you may extend this exception to your version of the
// library, but you are not obligated to do so.  If you do not wish to
// do so, delete this exception statement from your version.
//
// ---------------------------------------------------------------------------

import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

/**
 * A set of <code>(name =&gt; value)</code> pairs used in keyring entries.
 * Keys and values are simple strings, with the key never being empty and
 * always treated case-insensitively.
 */
public class Properties implements Cloneable {

   // Field.
   // ------------------------------------------------------------------------

   private HashMap props;

   // Constructor.
   // ------------------------------------------------------------------------

   /**
    * Creates a new properties object.
    */
   public Properties() {
      props = new HashMap();
   }

   // Instance methods.
   // ------------------------------------------------------------------------

   /**
    * Removes all properties from this object.
    */
   public void clear() {
      props.clear();
   }

   /**
    * Creates a copy of this properties object.
    *
    * @return The copy.
    */
   public Object clone() {
      Properties result = new Properties();
      result.props.putAll(props);
      return result;
   }

   /**
    * Tests if this object contains a given property name.
    *
    * @param key The key to test.
    * @return True if this object contains the given key.
    */
   public boolean containsKey(String key) {
      if (key == null || key.length() == 0) {
         return false;
      }
      return props.containsKey(canonicalize(key));
   }

   /**
    * Tests if this object contains a given property value.
    *
    * @param value The value to test.
    * @return True if this object contains the given value.
    */
   public boolean containsValue(String value) {
      if (value == null) {
         return false;
      }
      return props.containsValue(value);
   }

   /**
    * Adds a new property to this object.
    *
    * @param key The key, which can neither be null nor empty.
    * @param value The value, which cannot be null.
    * @return The old value mapped by the key, if any.
    * @throws IllegalArgumentException If either the key or value parameter

    *   is null, or if the key is empty.
    */
   public String put(String key, String value) {
      if (key == null || value == null || key.length() == 0) {
         throw new IllegalArgumentException("key nor value can be null");
      }
      return (String) props.put(canonicalize(key), value);
   }

   /**
    * Returns the value mapped by the given key, or null if there is no
    * such mapping.
    *
    * @param key
    */
   public String get(String key) {
      if (key == null || key.length() == 0) {
         return null;
      }
      return (String) props.get(canonicalize(key));
   }

   /**
    * Removes a key and its value from this object.
    *
    * @param key The key of the property to remove.
    * @return The old value mapped by the key, if any.
    */
   public String remove(String key) {
      if (key == null || key.length() == 0) {
         return null;
      }
      return (String) props.remove(canonicalize(key));
   }

   /**
    * Decodes a set of properties from the given input stream.
    *
    * @param in The input stream.
    * @throws IOException If an I/O error occurs.
    */
   public void decode(DataInputStream in) throws IOException {
      int len = in.readInt();
      MeteredInputStream min = new MeteredInputStream(in, len);
      DataInputStream in2 = new DataInputStream(min);
      while (!min.limitReached()) {
         String name = in2.readUTF();
         String value = in2.readUTF();
         put(name, value);
      }
   }

   /**
    * Encodes this set of properties to the given output stream.
    *
    * @param out The output stream to encode to.
    * @throws IOException If an I/O error occurs.
    */
   public void encode(DataOutputStream out) throws IOException {
      ByteArrayOutputStream buf = new ByteArrayOutputStream();
      DataOutputStream out2 = new DataOutputStream(buf);
      for (Iterator it = props.entrySet().iterator(); it.hasNext(); ) {
         Map.Entry entry = (Map.Entry) it.next();
         out2.writeUTF((String) entry.getKey());
         out2.writeUTF((String) entry.getValue());
      }
      out.writeInt(buf.size());
      buf.writeTo(out);
   }

   public String toString() {
      return props.toString();
   }

   // Own methods.
   // ------------------------------------------------------------------------

   private String canonicalize(String key) {
      return key.toLowerCase();
   }
}
