/*
 * @(#)file      SnmpMibOid.java
 * @(#)author    Sun Microsystems, Inc.
 * @(#)version   4.21
 * @(#)date      04/09/15
 *
 * 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;
import com.sun.jmx.snmp.SnmpValue;
import com.sun.jmx.snmp.SnmpVarBind;
import com.sun.jmx.snmp.SnmpStatusException;

/**
 * Represents a node in an SNMP MIB which is neither a group nor a variable.
 * This class defines a list of sub-nodes and the methods that allow to 
 * manipulate the sub-nodes.
 * <P>
 * This class is used internally and by the class 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     4.21     02/25/04
 * @author      Sun Microsystems, Inc
 */

public class SnmpMibOid extends SnmpMibNode implements Serializable {

    /**
     * Default constructor.
     */
    public SnmpMibOid() {
    }
    
    // PUBLIC METHODS
    //---------------
  
    /**
     * Generic handling of the <CODE>get</CODE> operation.
     *
     * <p> This method should be overridden in subclasses.
     * <p>
     *
     * @param req   The sub-request that must be handled by this node.
     *
     * @param depth The depth reached in the OID tree.
     *
     * @exception SnmpStatusException The default implementation (if not
     *            overridden) is to generate a SnmpStatusException.
     */
    public void get(SnmpMibSubRequest req, int depth) 
	throws SnmpStatusException {
        for (Enumeration e= req.getElements(); e.hasMoreElements();) {
            SnmpVarBind var= (SnmpVarBind) e.nextElement(); 
	    SnmpStatusException x = 
		new SnmpStatusException(SnmpStatusException.noSuchObject);
	    req.registerGetException(var,x);
	}
    }

    /**
     * Generic handling of the <CODE>set</CODE> operation.
     *
     * <p> This method should be overridden in subclasses.
     * <p>
     *
     * @param req   The sub-request that must be handled by this node.
     *
     * @param depth The depth reached in the OID tree.
     *
     * @exception SnmpStatusException The default implementation (if not
     *            overridden) is to generate a SnmpStatusException.
     */
    public void set(SnmpMibSubRequest req, int depth) 
	throws SnmpStatusException {
        for (Enumeration e= req.getElements(); e.hasMoreElements();) {
            SnmpVarBind var= (SnmpVarBind) e.nextElement(); 
	    SnmpStatusException x = 
		new SnmpStatusException(SnmpStatusException.noAccess);
	    req.registerSetException(var,x);
	}
    }

    /**
     * Generic handling of the <CODE>check</CODE> operation.
     *
     * <p> This method should be overridden in subclasses.
     * <p>
     *
     * @param req   The sub-request that must be handled by this node.
     *
     * @param depth The depth reached in the OID tree.
     *
     * @exception SnmpStatusException The default implementation (if not
     *            overriden) is to generate a SnmpStatusException.
     */
    public void check(SnmpMibSubRequest req, int depth) 
	throws SnmpStatusException {
        for (Enumeration e= req.getElements(); e.hasMoreElements();) {
            SnmpVarBind var= (SnmpVarBind) e.nextElement(); 
	    SnmpStatusException x = 
		new SnmpStatusException(SnmpStatusException.noAccess);
	    req.registerCheckException(var,x);
	}
    }



    // ---------------------------------------------------------------------
    //
    // Implements the method defined in SnmpMibNode.
    //
    // ---------------------------------------------------------------------
    //
    void findHandlingNode(SnmpVarBind varbind, 
			  long[] oid, int depth, 
			  SnmpRequestTree handlers) 
	throws SnmpStatusException {


	final int length = oid.length;
	SnmpMibNode node = null;
	
	if (handlers == null)
            throw new SnmpStatusException(SnmpStatusException.snmpRspGenErr);

	if (depth > length) {
	    // Nothing is left... the oid is not valid
            throw noSuchObjectException;

	} else if (depth == length) {
	    // The oid is not complete...
	    throw noSuchInstanceException;

	} else {
	    // Some children variable or subobject is being querried
	    // getChild() will raise an exception if no child is found.
	    // 
	    final SnmpMibNode child= getChild(oid[depth]);

	    // XXXX zzzz : what about null children? 
	    //             (variables for nested groups)
	    // if child==null, then we're dealing with a variable or
	    // a table: we register this node. 
	    // This behaviour should be overriden in subclasses,
	    // in particular in group meta classes: the group
	    // meta classes that hold tables should take care
	    // of forwarding this call to all the tables involved.
	    //
	    if (child == null)  
		handlers.add(this,depth,varbind);
	    else 
		child.findHandlingNode(varbind,oid,depth+1,handlers);
	}
    }

    // ---------------------------------------------------------------------
    //
    // Implements the method defined in SnmpMibNode.
    //
    // ---------------------------------------------------------------------
    //
    long[] findNextHandlingNode(SnmpVarBind varbind, 
				long[] oid, int pos, int depth, 
				SnmpRequestTree handlers,
				AcmChecker checker) 
	throws SnmpStatusException {


	final int length = oid.length;
	SnmpMibNode node = null;
	long[] result = null;
	if (handlers == null)
	    // This should be considered as a genErr, but we do not want to
	    // abort the whole request, so we're going to throw
	    // a noSuchObject...
	    //
            throw noSuchObjectException;

	final Object data = handlers.getUserData();
	final int pduVersion = handlers.getRequestPduVersion();

        if (pos >= length) {
            long[] newOid= new long[1];
	    newOid[0]=  getNextVarId(-1,data,pduVersion);
            result = findNextHandlingNode(varbind,newOid,0,depth,handlers,
					  checker);
	    return result;
        }

        // search the element specified in the oid
        //
        long[] newOid= new long[1];
        long index= oid[pos];
   
        while (true) {
     
            try {
                final SnmpMibNode child = getChild(index);
		// SnmpOid result = null;
		if (child == null) {
		    // shouldn't happen
		    throw noSuchObjectException;
		    // validateVarId(index);
		    // handlers.add(this,varbind,depth);
		    // result = new SnmpOid(0);
		} else {
		    checker.add(depth, index);
		    try {
			result = child.findNextHandlingNode(varbind,oid,pos+1,
							    depth+1,handlers, 
							    checker);
		    } finally {
			checker.remove(depth);
		    } 
		}
		
		// Build up the leaf OID
                result[depth] = index;
                return result;
		
            } catch(SnmpStatusException e) {
                // If there is no such element go one level up ...
                //
                index= getNextVarId(index,data,pduVersion);

                // There is no need to carry the original oid ...
                newOid[0]=index;
                pos= 1;
                oid=newOid;	
            }
        }
    }


    /**
     * Computes the root OID of the MIB.
     */
    public void getRootOid(Vector result) {

        // If a node has several children, let assume that we are one step to
        // far in order to get the MIB root.
        //
        if (nbChildren != 1)
            return;
        
        result.addElement(new Integer(varList[0]));

        // Now query our child.
        //
        ((SnmpMibNode)children.firstElement()).getRootOid(result);
    
    }

    /**
     * Registers a specific node in the tree.
     */
    public void registerNode(String oidString ,SnmpMibNode node) 
	throws IllegalAccessException {
        SnmpOid oid= new SnmpOid(oidString);
        registerNode(oid.longValue(), 0, node);
    }
    
    // PROTECTED METHODS
    //------------------
    
    /**
     * Registers a specific node in the tree.
     */
    void registerNode(long[] oid, int cursor ,SnmpMibNode node) 
	throws IllegalAccessException {
        
        if (cursor >= oid.length)
            throw new IllegalAccessException();
    
        // Check if the node is already defined 
        //
        long var= oid[cursor];

        //System.out.println("entering registration for val=" 
	// + String.valueOf(var) + " position= " + cursor);

        int pos = retrieveIndex(var);
        if (pos  == nbChildren) {
            nbChildren++;
            varList= new int[nbChildren];
            varList[0]= (int) var;
            pos =0;
            if ( (cursor + 1) == oid.length) {
                // That 's the end of the trip. 
		// Do not forward the registration 

                //System.out.println("End of trip for val=" 
		//      + String.valueOf(var) + " position= " + cursor);
                children.insertElementAt(node,pos);
                return;
            }

            //System.out.println("Create node for val=" 
	    //       + String.valueOf(var) + " position= " + cursor);
            SnmpMibOid child= new SnmpMibOid();
            children.insertElementAt(child, pos);
            child.registerNode(oid, cursor + 1, node);
            return;
        }
        if (pos == -1) {
            // The node is not yet registered
            //
            int[] tmp= new int[nbChildren + 1];
            tmp[nbChildren]= (int) var;
            System.arraycopy(varList, 0, tmp, 0, nbChildren);
            varList= tmp;
            nbChildren++;
            SnmpMibNode.sort(varList);
            int newPos = retrieveIndex(var);
            varList[newPos]= (int) var;
            if ( (cursor + 1) == oid.length) {
                // That 's the end of the trip.
		// Do not forward the registration 
                
                //System.out.println("End of trip for val=" 
		//     + String.valueOf(var) + " position= " + cursor);
                children.insertElementAt(node, newPos);
                return;
            }
            SnmpMibOid child= new SnmpMibOid();
            // System.out.println("Create node for val=" + 
	    //     String.valueOf(var) + " position= " + cursor);
            children.insertElementAt(child, newPos);
            child.registerNode(oid, cursor + 1, node);
            return;
        } 
        else {
            // The node is already registered
            //
            SnmpMibNode child= (SnmpMibNode) children.elementAt(pos);
            if ( (cursor + 1) == oid.length ) {
                //System.out.println("Node already registered val=" + 
		//          String.valueOf(var) + " position= " + cursor);
		if (child == node) return;
		if (child != null && node != null) {
		    // Now we're going to patch the tree the following way:
		    //   if a subgroup has been registered before its father,
		    //   we're going to replace the father OID node with 
		    //   the actual group-node and export the children from 
		    //   the temporary OID node to the actual group node.
		    //

		    if (node instanceof SnmpMibGroup) {
			// `node' is a group => replace `child' with `node'
			// export the child's subtree to `node'.
			//
			((SnmpMibOid)child).exportChildren((SnmpMibOid)node);
			children.setElementAt(node,pos);
			return;

		    } else if ((node instanceof SnmpMibOid) &&
			     (child instanceof SnmpMibGroup)) {
			// `node' is a temporary node, and `child' is a 
			//  group => keep child and export the node's 
			//  subtree to `child'.
			//
			((SnmpMibOid)node).exportChildren((SnmpMibOid)child);
			return;
		    } else if (node instanceof SnmpMibOid) {
			// `node' and `child' are both temporary OID nodes
			// => replace `child' with `node' and export child's
			// subtree to `node'.
			//
			((SnmpMibOid)child).exportChildren((SnmpMibOid)node);
			children.setElementAt(node,pos);
			return;
		    }
		}
		children.setElementAt(node,pos);
                return;
            } else {
		if (child == null)
		    throw new IllegalAccessException();
                ((SnmpMibOid)child).registerNode(oid, cursor + 1, node);
            }
        }
    }
    
    /**
     * Export this node's children to a brother node that will replace
     * this node in the OID tree.
     * This method is a patch that fixes the problem of registering
     * a subnode before its father node.
     *
     **/
    void exportChildren(SnmpMibOid brother) 
	throws IllegalAccessException {
	
	if (brother == null) return;
	final long[] oid = new long[1];
	for (int i=0; i<nbChildren; i++) {
	    final SnmpMibNode child = (SnmpMibNode)children.elementAt(i);
	    if (child == null) continue;
	    oid[0] = varList[i];
	    brother.registerNode(oid,0,child);
	}
    }

    // PRIVATE METHODS
    //----------------
  
    SnmpMibNode getChild(long id) throws SnmpStatusException {
        
        // first we need to retrieve the identifier in the list of children 
        //
        final int pos= getInsertAt(id);
        if (pos >= nbChildren)
            throw noSuchObjectException;
    
        if (varList[pos] != (int) id) 
            throw noSuchObjectException;

        // Access the node
        //
	SnmpMibNode child = null;
        try {
            child = (SnmpMibNode) children.elementAtNonSync(pos);
        } catch(ArrayIndexOutOfBoundsException e) {
            throw noSuchObjectException;
        }
	if (child == null) 
            throw noSuchInstanceException;
	return child;
    }
  
    private int retrieveIndex(long val) {

        int low= 0;
        int cursor= (int) val;
	if (varList == null || varList.length < 1) 
	    return nbChildren;

        int max= varList.length -1 ;
        int curr= low + (max-low)/2;
        int elmt= 0;
        while (low <= max) {
            elmt= varList[curr];
            if (cursor == elmt) {
                // We need to get the next index ...
                //
                return curr;
            }  
            if (elmt < cursor) {
                low= curr +1;
            } else {
                max= curr -1;
            }  
            curr= low + (max-low)/2;
        }
        return -1;
    }
  
    private int getInsertAt(long val) {
        
        int low= 0;
        final int index= (int) val;
	if (varList == null) 
            return -1;
        int max= varList.length -1 ;
        int elmt=0;
	//final int[] v = varList;

        //if (index > a[max])
        //return max +1;
    
  
        int curr= low + (max-low)/2;    
        while (low <= max) {

            elmt= varList[curr];

            // never know ...we might find something ...
            // 
            if (index == elmt)
                return curr;

            if (elmt < index) {
                low= curr +1;
            } else {
                max= curr -1;
            }  
            curr= low + (max-low)/2;
        }

        return curr;
    }
    
    // PRIVATE VARIABLES
    //------------------

    /**
     * Contains the list of sub nodes.
     */
    private NonSyncVector children=  new NonSyncVector(1);
    
    /**
     * The number of sub nodes.
     */
    private int nbChildren= 0;
    
    
    // All the methods of the Vector class are synchronized.
    // Synchronization is a very expensive operation. In our case it is 
    // not always required...
    //
    class NonSyncVector extends Vector {
	
        public NonSyncVector(int size) {
            super(size);
        }
	
        final void addNonSyncElement(Object obj) {
            ensureCapacity(elementCount + 1);
            elementData[elementCount++] = obj;
        }
	
        final Object elementAtNonSync(int index) {
            return elementData[index];
        }
	
    }
}