WordGram.java

public class WordGram 
{
    private String[] myWords;
    private int myHash;

    public WordGram(String[] source, int start, int size) 
    {
        myWords = new String[size];
        System.arraycopy(source, start, myWords, 0, size);
    }
    public String wordAt(int index) 
    {
        if (index < 0 || index >= myWords.length) 
        {
            throw new IndexOutOfBoundsException("bad index in wordAt "+index);
        }
        return myWords[index];
    }

    public int length()
    {
        return myWords.length;
    }

    public String toString()
    {
        String ret = "";
        for(int i=0;i<myWords.length;i++)
        {
            ret +=myWords[i]+" ";
        }   
        return ret.trim();
    }

    public boolean equals(Object o) 
    {
        WordGram other = (WordGram) o;
        
        if(this.length() != other.length())
        {
            return false;
        }
        for(int i=0;i<myWords.length;i++)
        {
            if(!(myWords[i].equals(other.myWords[i])))
            {
                return false;
            }
        }
        return true;
    }

    public WordGram shiftAdd(String word) 
    { 
        WordGram out = new WordGram(myWords, 0, myWords.length);

        for(int i=0; i<out.myWords.length-1;i++)
        {
            out.myWords[i] = out.myWords[i+1];
        }
        out.myWords[myWords.length-1]=word;
        return out;
    }
    public int hashCode ()
    {
        return toString().hashCode();
    }
}