package edu.stanford.nlp.util;import java.util.*;/** *  Interner: Class for interning things.  * *  It maps any object given to an interned version.  If presented with a  *  new object which has no interned version, the presented object becomes *  the interned version. * *  Author: Dan Klein *  Date: 1/3/01 * * @author Dan Klein */public final class Interner {  private Map entries = new HashMap();  class InternerEntry {    Internable i;    public Internable entry() {      return i;    }    public void setEntry(Internable i) {      this.i = i;    }    public int hashCode() {      return i.weakHashCode();    }    public boolean equals(Object o) {      //if (o instanceof InternerEntry)      return i.weakEquals(((InternerEntry)o).i);      //else      //return i.weakEquals(o);    }    InternerEntry(Internable i) {      this.i = i;    }    InternerEntry() {      i = null;    }  }  private transient InternerEntry tempEntry = new InternerEntry();  public Object intern(Internable o) {    //if (o instanceof Internable)    //InternerEntry e = new InternerEntry(o);    tempEntry.setEntry(o);    Object internedVersion = entries.get(tempEntry);    if (internedVersion == null) {      entries.put(tempEntry, tempEntry);      internedVersion = tempEntry;      tempEntry = new InternerEntry();    }    //if (internedVersion instanceof InternerEntry)    return ((InternerEntry)internedVersion).entry();    //return o;  }  /*  public boolean contains(Object o) {    if (o instanceof Internable)      o = new InternerEntry((Internable)o);    Object internedVersion = entries.get(o);    if (internedVersion == null)      return false;    return true;  }  */}