/*
 * @(#)file      SnmpIndex.java
 * @(#)author    Sun Microsystems, Inc.
 * @(#)version   4.8
 * @(#)date      05/04/13
 *
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 */


package com.sun.jmx.snmp.agent;



// java imports
//
import java.io.Serializable;
import java.util.Vector;
import java.util.Enumeration;

// jmx imports
//
import com.sun.jmx.snmp.SnmpOid;

/**
 * Represents a SNMP index.
 * An <CODE>SnmpIndex</CODE> is represented as a <CODE>Vector</CODE> of <CODE>SnmpOid</CODE>.
 * <P>
 * This class is used internally and by the classes generated by <CODE>mibgen</CODE>.
 * You should not need to use this class directly.
 *
 * <p><b>This API is a Sun Microsystems internal API  and is subject 
 * to change without notice.</b></p>
 * @version     4.8     12/19/03
 * @author      Sun Microsystems, Inc
 */

public class SnmpIndex implements Serializable {
  
    /**
     * Initializes an <CODE>SnmpIndex</CODE> using a vector of object identifiers.
     * <P>Following the RFC recommendations, every syntax that is used as a
     * table index should have an object identifier representation. There are
     * some guidelines on how to map the different syntaxes into an object identifier.
     * In the different <CODE>SnmpValue</CODE> classes provided, there is a <CODE>toOid</CODE> method to get
     * the object identifier of the value.
     *
     * @param oidList The list of Object Identifiers.
     */
    public SnmpIndex(SnmpOid[] oidList) {
        size= oidList.length;
        for(int i= 0; i <size; i++) {
            // The order is important ...
            //
            oids.addElement(oidList[i]);
        }
    }
 
    /**
     * Initializes an <CODE>SnmpIndex</CODE> using the specified Object Identifier.
     *
     * @param oid The Object Identifier.
     */
    public SnmpIndex(SnmpOid oid) {
        oids.addElement(oid);
        size= 1;
    }
  
    /**
     * Gets the number of Object Identifiers the index is made of.
     *
     * @return The number of Object Identifiers.
     */
    public int getNbComponents() {
        return size;
    }
  
    /**
     * Gets the index as a vector of Object Identifiers.
     *
     * @return The index as a vector.
     */
    public Vector getComponents() {
        return oids;
    }
  
    /**
     * Compares two indexes for equality.
     *
     * @param index The index to compare <CODE>this</CODE> with.
     *
     * @return <CODE>true</CODE> if the two indexes are equal, <CODE>false</CODE> otherwise.
     */
    public boolean equals(SnmpIndex index) {
        
        if (size != index.getNbComponents())
            return false;
    
        // The two vectors have the same length.
        // Compare each single element ...
        //
        SnmpOid oid1;
        SnmpOid oid2;
        Vector components= index.getComponents();
        for(int i=0; i <size; i++) {
            oid1= (SnmpOid) oids.elementAt(i);
            oid2= (SnmpOid) components.elementAt(i);
            if (oid1.equals(oid2) == false)
                return false;
        }
        return true;
    }
  
    /**
     * Compares two indexes.
     *
     * @param index The index to compare <CODE>this</CODE> with.
     *
     * @return The value 0 if the two OID vectors have the same elements, another value otherwise.
     */
    public int compareTo(SnmpIndex index) {
    
        int length= index.getNbComponents();
        Vector components= index.getComponents();
        SnmpOid oid1;
        SnmpOid oid2;
        int comp;
        for(int i=0; i < size; i++) {
            if ( i > length) {
                // There is no more element in the index
                //
                return 1;
            }
            // Access the element ...
            //
            oid1= (SnmpOid) oids.elementAt(i);
            oid2= (SnmpOid) components.elementAt(i);
            comp= oid1.compareTo(oid2);
            if (comp == 0)
                continue;
            return comp;
        }
        return 0;     
    }
  
    /**
     * Returns a <CODE>String</CODE> representation of the index.
     * The different elements are separated by "//".
     *
     * @return A string representation of the index.
     */
    public String toString() {
        StringBuffer msg= new StringBuffer();
        for(Enumeration e= oids.elements(); e.hasMoreElements(); ) {
            SnmpOid val= (SnmpOid) e.nextElement();
            msg.append( "//" + val.toString());
        }
        return msg.toString();
    }
    
    // PRIVATE VARIABLES
    //------------------
  
    /**
     * The list of OIDs.
     * @serial
     */
    private Vector oids = new Vector();

    /**
     * The number of elements in the index.
     * @serial
     */
    private int size = 0;
}
