properties.java

linux下建立JAVA虚拟机的源码KAFFE

/* Properties.java -- 
   Copyright (C) 2003, 2006 Free Software Foundation, Inc.

This file is a 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 of the License, or (at
your option) any later version.

GNU Classpath 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 GNU Classpath; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, 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.  */


package gnu.javax.crypto.keyring;

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();
  }
}