---

HashPool.java

package gov.nasa.arc.ase.util;

import java.util.*;

public class HashPool {
  public class PoolEntry {
    private PoolObject obj;
    private int idx;

    public PoolEntry(PoolObject o, int i) {
      obj = o;
      idx = i;
    }

    public PoolObject getObject() {
      return obj;
    }

    public int getIndex() {
      return idx;
    }

    public int hashCode() {
      return idx;
    }

    public boolean equals(Object obj) {
      PoolEntry other = (PoolEntry)obj;
      return (other.idx == idx);
    }
  }

  private Hashtable pool;
  private int size = 0;
  private PoolObject[] objects;

  public HashPool() {
    pool  = new Hashtable();
    objects = new PoolObject[1];
    objects[0] = null;
  }  
  public PoolObject get(PoolObject o) {
    if(o == null) return null;
    PoolEntry e = (PoolEntry)pool.get(o);
    if (e != null)
      return e.obj;
    else {
      pool.put(o,new PoolEntry(o,size+1));
      if(objects.length < size+2) {
    PoolObject[] old = objects;
    objects = new PoolObject[size+10];
    System.arraycopy(old, 0, objects, 0, old.length);
      }
      objects[size+1] = o;
    }
    size++;

    return o;
  }  
  public PoolEntry getEntry(PoolObject o) {
    if(o == null) return null;
    PoolEntry e = (PoolEntry)pool.get(o);
    if (e == null) {
      pool.put(o,e = new PoolEntry(o,size+1));
      if(objects.length < size+2) {
    PoolObject[] old = objects;
    objects = new PoolObject[size+10];
    System.arraycopy(old, 0, objects, 0, old.length);
      }
      objects[size+1] = o;
    } else
      return e;
    size++;

    return e;
  }  
  public int getIndex(PoolObject o) {
    if(o == null) return -1;
    PoolEntry e = (PoolEntry)pool.get(o);
    if (e != null) 
      return e.idx;
    else  {
      pool.put(o,new PoolEntry(o,size+1));
      if(objects.length < size+2) {
    PoolObject[] old = objects;
    objects = new PoolObject[size+10];
    System.arraycopy(old, 0, objects, 0, old.length);
      }
      objects[size+1] = o;
    }
    size++;

    return size;
  }  
  public PoolObject getObject(int idx) {
    return objects[idx];
  }  
  public int size() {
    return size;
  }  
}

---