Source code: com/hartmath/expression/HString.java

   /*
    *  HString.java
    *  Copyright (C) 2000 Klaus Hartlage
    *
    *  This program 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 any later version.
    *
   *  This program 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; if not, write to the Free Software
   *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
   */
  package com.hartmath.expression;
  
  import java.lang.*;
  import java.io.*;
  import com.hartmath.lib.C;
  import com.hartmath.lib.Session;
  
  /**
   *  The HString class represents character strings. This class adopts much of
   *  its functionality from the <code>java.lang.String</code> class
   *
   *@see        HSymbol
   */
  public class HString extends HExpression {
    /**
     *  Description of the Field
     */
    protected String str;
  
  
    /**
     *  Constructs a new empty HString.
     */
    public HString() {
      this.str = new String();
    }
  
  
    /**
     *  Constructs a new HString that is a copy of the specified String.
     *
     *@param  value  the initial value of the HString
     */
    public HString(String value) {
      this.str = new String(value);
    }
  
  
    /**
     *  Constructs a new HString whose initial value is the specified array of
     *  characters.
     *
     *@param  value  the initial value of the HString
     */
    public HString(char value[]) {
      this.str = new String(value);
    }
  
  
    /**
     *  Constructs a new HString whose initial value is the specified sub array of
     *  characters. The length of the new string will be count characters starting
     *  at offset within the specified character array.
     *
     *@param  value   the initial value of the HString, an array of characters
     *@param  offset  the offset into the value of the HString
     *@param  count   the length of the value of the HString
     */
    public HString(char value[], int offset, int count) {
      this.str = new String(value, offset, count);
    }
  
  
    public HString(StringBuffer buffer) {
      this.str = new String(buffer);
    }
  
    /**
     *  Method Declaration.
     *
     *@param  obj
     *@return
     *@see
     */
    public boolean isMember(HObject obj) {
      return equals(obj);
    }
  
  
    /**
     *  Method Declaration.
    *
    *@param  sym
    *@return
    *@see
    */
   public boolean isHeadMember(HSymbol sym) {
     return head().equals(sym);
   }
   
   /**
    *  Transform this in a <code>String</code> object
    *
    *@return    the internal <code>String</code> object
    */
   public String toString() {
     return str;
   }
 
   /**
       * Returns a hash code value for the object. This method is 
       * supported for the benefit of hashtables such as those provided by 
       * <code>java.util.Hashtable</code>.
       * <p>
       *
       * @return  a hash code value for this object.
       * @see     java.lang.Object#equals(java.lang.Object)
       * @see     java.util.Hashtable
       */
   public int hashCode() {
     return (str.hashCode() & 0x55555555);
   }
 
 
   /**
    *  Method Declaration.
    *
    *@param  obj
    *@return
    *@see
    */
   public boolean equals(Object obj) {
     if (obj instanceof HString) {
       return str.equals(((HString) obj).str);
     }
 
     return false;
   }
 
 
   /**
    *  Method Declaration.
    *
    *@param  obj
    *@return
    *@see
    */
   public int compareTo(HString obj) {
     return str.compareTo(obj.str);
   }
 
 
   /**
    *  Method Declaration.
    *
    *@param  obj
    *@param  session  Description of Parameter
    *@return
    *@see
    */
   public boolean less(Session session, Object obj) {
     if (obj instanceof HString) {
       HString temp = (HString) obj;
 
       return (str.compareTo(temp.str) < 0);
     }
     if (obj instanceof HObject) {
       return (hierarchy() < ((HObject) obj).hierarchy());
     }
 
     return false;
   }
 
 
   /**
    *  Method Declaration.
    *
    *@param  obj
    *@param  session  Description of Parameter
    *@return
    *@see
    */
   public boolean greater(Session session, Object obj) {
     if (obj instanceof HObject) {
       return ((HObject) obj).less(session, this);
     }
 
     return false;
   }
 
 
   /**
    *  Returns an specific integer value for each class in the math-objects
    *  hierarchy
    *
    *@return    Description of the Returned Value
    */
   public int hierarchy() {
     return HObject.STRINGID;
   }
 
 
   /**
    *  Method Declaration.
    *
    *@return    Description of the Returned Value
    *@see
    */
   /*
    *  public void writeTo(DataOutputStream os) throws IOException {
    *  os.writeByte(HObject.STRINGFILEID);
    *  os.writeUTF(str);
    *  }
    */
   public HSymbol head() {
     return C.String;
   }
 
 }