package edu.stanford.nlp.util;import java.util.*;/** * Collection of useful static methods for working with Collections. Includes * methods to increment counts in maps and cast list/map elements to common types. * * @author Joseph Smarr (jsmarr@stanford.edu) */public class CollectionUtils{    /** Private constructor to prevent direct instantiation. */    private CollectionUtils() { }        /**     * Adds the given delta to the Integer value stored for the given key in     * the given Map. Returns whether the entry had to be created (i.e. it wasn't     * in the map), in which case it's inserted with delta as the initial value.     * @param map Map from keys to Integer values representing key counts     * @param key key in map for Integer to increment     * @param delta amount to change Integer value count by     * @return whether a new entry for the given key was created in the process (i.e.     * if it wasn't in the map before).     */    public static boolean incrementCount(Map map,Object key,int delta)    {        boolean created=false;        Integer count=(Integer)map.get(key);        if(count==null)        {            count=new Integer(0);            created=true;        }        map.put(key,new Integer(count.intValue()+delta));        return(created);    }        /**      * Increments the Integer count of the given key in the given Map by 1.     * @see #incrementCount(Map,String,int)     */    public static boolean incrementCount(Map map,Object key)    {        return(incrementCount(map,key,1));    }        // list casting methods        /** Returns <tt>(String)list.get(index)</tt>. */    public static String getString(List list,int index)    {        return((String)list.get(index));    }        /** Returns <tt>(Integer)list.get(index)</tt>. */    public static Integer getInteger(List list,int index)    {        return((Integer)list.get(index));    }        /** Returns <tt>((Integer)list.get(index)).intValue()</tt>. */    public static int getInt(List list,int index)    {        return(getInteger(list,index).intValue());    }        /** Returns <tt>(Double)list.get(index)</tt>. */    public static Double getDouble(List list,int index)    {        return((Double)list.get(index));    }        /** Returns <tt>((Double)list.get(index)).doubleValue()</tt>. */    public static double getdouble(List list,int index)    {        return(getDouble(list,index).doubleValue());    }        /** Returns <tt>((Boolean)list.get(index)).booleanValue()</tt>. */    public static boolean getBoolean(List list,int index)    {        return(((Boolean)list.get(index)).booleanValue());    }            // map casting methods            /** Returns <tt>(String)map.get(key)</tt>. */    public static String getString(Map map,Object key)    {        return((String)map.get(key));    }        /** Returns <tt>(Integer)map.get(key)</tt>. */    public static Integer getInteger(Map map,Object key)    {        return((Integer)map.get(key));    }        /** Returns <tt>((Integer)map.get(key)).intValue()</tt>. */    public static int getInt(Map list,Object key)    {        return(getInteger(list,key).intValue());    }        /** Returns <tt>(Double)map.get(key)</tt>. */    public static Double getDouble(Map map,Object key)    {        return((Double)map.get(key));    }        /** Returns <tt>((Double)map.get(key)).doubleValue()</tt>. */    public static double getdouble(Map map,Object key)    {        return(getDouble(map,key).doubleValue());    }        /** Returns <tt>((Boolean)map.get(key)).booleanValue()</tt>. */    public static boolean getBoolean(Map map,Object key)    {        return(((Boolean)map.get(key)).booleanValue());    }    }