Node.java

package com.sleepycat.je.tree;
import java.nio.ByteBuffer;
import com.sleepycat.je.DatabaseException;
import com.sleepycat.je.cleaner.UtilizationTracker;
import com.sleepycat.je.dbi.DatabaseImpl;
import com.sleepycat.je.dbi.INList;
import com.sleepycat.je.log.LogEntryType;
import com.sleepycat.je.log.LogException;
import com.sleepycat.je.log.LogReadable;
import com.sleepycat.je.log.LogUtils;
import com.sleepycat.je.log.LogWritable;
import com.sleepycat.je.log.LoggableObject;
import de.ovgu.cide.jakutil.*;
/** 
 * A Node contains all the common base information for any JE B-Tree node.
 */
public abstract class Node implements LoggableObject, LogReadable, LogWritable {
  public synchronized static void setLastNodeId(  long id){
    if (lastAllocatedId < id) {
      lastAllocatedId=id;
    }
  }
  private static long lastAllocatedId=0;
  private static final String BEGIN_TAG="<node>";
  private static final String END_TAG="</node>";
  private long nodeId;
  /** 
 * Disallow use
 */
  private Node(){
  }
  /** 
 * Create a new node, assigning it the next available node id.
 */
  protected Node(  boolean init){
    if (init) {
      nodeId=getNextNodeId();
    }
  }
  /** 
 * Increment and return the next usable id. Must be synchronized.
 */
  public static synchronized long getNextNodeId(){
    return ++lastAllocatedId;
  }
  /** 
 * Get the latest id, for checkpointing.
 */
  public static synchronized long getLastId(){
    return lastAllocatedId;
  }
  /** 
 * Initialize a node that has been faulted in from the log
 */
  public void postFetchInit(  DatabaseImpl db,  long sourceLsn) throws DatabaseException {
  }
  public long getNodeId(){
    return nodeId;
  }
  void setNodeId(  long nid){
    nodeId=nid;
  }
  public void verify(  byte[] maxKey) throws DatabaseException {
  }
  /** 
 * @return true if this node is a duplicate-bearing node type, false
 * if otherwise.
 */
  public boolean containsDuplicates(){
    return false;
  }
  /** 
 * Cover for LN's and just return 0 since they'll always be at the bottom
 * of the tree.
 */
  int getLevel(){
    return 0;
  }
  boolean matchLNByNodeId(  TreeLocation location,  long nodeId) throws DatabaseException {
    throw new DatabaseException("matchLNByNodeId called on non DIN/DBIN");
  }
  /** 
 * Add yourself to the in memory list if you're a type of node that 
 * should belong.
 */
  abstract void rebuildINList(  INList inList) throws DatabaseException ;
  /** 
 * Remove yourself from the in memory list if you're a type of node that 
 * is put there.
 */
  abstract void accountForSubtreeRemoval(  INList inList,  UtilizationTracker tracker) throws DatabaseException ;
  /** 
 * @return true if you're part of a deletable subtree.
 */
  abstract boolean isValidForDelete() throws DatabaseException ;
  /** 
 * @return true if you're an IN in the search path
 */
  abstract protected boolean isSoughtNode(  long nid,  boolean updateGeneration) throws DatabaseException ;
  /** 
 * @return true if you can be the ancestor of the target IN.
 * Currently the determining factor is whether the target IN contains
 * duplicates.
 */
  abstract protected boolean canBeAncestor(  boolean targetContainsDuplicates);
  /** 
 * Return the approximate size of this node in memory, if this
 * size should be included in it's parents memory accounting. 
 * For example, all INs return 0, because they are accounted for 
 * individually. LNs must return a count, they're not counted on
 * the INList.
 */
  protected long getMemorySizeIncludedByParent(){
    return 0;
  }
  /** 
 * Default toString method at the root of the tree.
 */
  public String toString(){
    return this.dumpString(0,true);
  }
  private String beginTag(){
    return BEGIN_TAG;
  }
  private String endTag(){
    return END_TAG;
  }
  public void dump(  int nSpaces){
    System.out.print(dumpString(nSpaces,true));
  }
  String dumpString(  int nSpaces,  boolean dumpTags){
    StringBuffer self=new StringBuffer();
    self.append(TreeUtils.indent(nSpaces));
    if (dumpTags) {
      self.append(beginTag());
    }
    self.append(nodeId);
    if (dumpTags) {
      self.append(endTag());
    }
    return self.toString();
  }
  public String shortDescription(){
    return "<" + getType() + "/"+ getNodeId();
  }
  public String getType(){
    return getClass().getName();
  }
  /** 
 * @see LoggableObject#getLogType
 */
  public abstract LogEntryType getLogType();
  /** 
 * @see LoggableObject#marshallOutsideWriteLatchBy default, nodes can be marshalled outside the log write latch.
 */
  public boolean marshallOutsideWriteLatch(){
    return true;
  }
  /** 
 * @see LoggableObject#countAsObsoleteWhenLogged
 */
  public boolean countAsObsoleteWhenLogged(){
    return false;
  }
  /** 
 * @see LoggableObject#postLogWork
 */
  public void postLogWork(  long justLoggedLsn) throws DatabaseException {
  }
  /** 
 * @see LoggableObject#getLogSize
 */
  public int getLogSize(){
    return LogUtils.LONG_BYTES;
  }
  /** 
 * @see LogWritable#writeToLog
 */
  public void writeToLog(  ByteBuffer logBuffer){
    LogUtils.writeLong(logBuffer,nodeId);
  }
  /** 
 * @see LogReadable#readFromLog
 */
  public void readFromLog(  ByteBuffer itemBuffer,  byte entryTypeVersion) throws LogException {
    nodeId=LogUtils.readLong(itemBuffer);
  }
  /** 
 * @see LogReadable#dumpLog
 */
  public void dumpLog(  StringBuffer sb,  boolean verbose){
    sb.append(BEGIN_TAG);
    sb.append(nodeId);
    sb.append(END_TAG);
  }
}