import java.io.*;import java.util.*;public class LexAnalyzer {	private ArrayList<Word> wordList;	private ArrayList<String> errorList;	private String[] keyWord={"int","if","else","do","while","read","write"};	private int keyWordIndex=-1,line =1;	public boolean isKeyWord(String word)	{		boolean isKeyWord=false;		for(int i=0;i<keyWord.length;i++)		{			if(word.equals(keyWord[i]))			{				isKeyWord=true;				keyWordIndex=i;			}		}		return isKeyWord;	}	public ArrayList<Word> analysis(String source)	{		wordList = new ArrayList<Word>();		errorList = new ArrayList<String>();		String tempSource = source.replaceAll("(\t|\\ ){1,}", "\\ ");		String tempWord="";		char[] sourceChar = tempSource.toCharArray();		int charIndex=0,state=1,totalCharIndex=sourceChar.length-1;		while(charIndex<totalCharIndex)		{			switch(state)			{				case(1):				{					if(Character.isLetter(sourceChar[charIndex]))					{						tempWord+=sourceChar[charIndex];						charIndex++;						state=3;					}					else if(Character.isDigit(sourceChar[charIndex]))					{						tempWord+=sourceChar[charIndex];						charIndex++;						state=8;					}					else if(Character.isWhitespace(sourceChar[charIndex])||Character.isISOControl(sourceChar[charIndex]))//'\n'是whiteSpace?					{						if(sourceChar[charIndex]=='\n')line++;						tempWord="";						charIndex++;						state=1;					}					else					{						switch(sourceChar[charIndex])						{						case('+'):state=6;								  tempWord+=sourceChar[charIndex];								  charIndex++;								  break;						case('-'):state=7;								  tempWord+=sourceChar[charIndex];						          charIndex++;						          break;						case('*'):tempWord+=sourceChar[charIndex];						  		  wordList.add(new Word(tempWord,"MULTYPLY",line));						          tempWord="";						          charIndex++;						          state=1;						          break;						case('/'):tempWord+=sourceChar[charIndex];						  		  wordList.add(new Word(tempWord,"DIVISION",line));						          tempWord="";						          charIndex++;						          state=1;						          break;						case(','):tempWord+=sourceChar[charIndex];						  		  wordList.add(new Word(tempWord,"COMM",line));						          tempWord="";						          charIndex++;						          state=1;						          break;						case(';'):tempWord+=sourceChar[charIndex];						  		  wordList.add(new Word(tempWord,"SEMICOLON",line));						          tempWord="";						          charIndex++;						          state=1;						          break;						case('('):tempWord+=sourceChar[charIndex];						  		  wordList.add(new Word(tempWord,"LEFT(",line));						          tempWord="";						          charIndex++;						          state=1;						          break;						case(')'):tempWord+=sourceChar[charIndex];						  		  wordList.add(new Word(tempWord,"RIGHT)",line));						          tempWord="";						          charIndex++;						          state=1;						          break;						case('.'):tempWord+=sourceChar[charIndex];				  		  		  wordList.add(new Word(tempWord,"DOT",line));						          tempWord="";						          charIndex++;						          state=1;						          break;						case('"'):tempWord+=sourceChar[charIndex];						  		  wordList.add(new Word(tempWord,"DOUBLECOMM",line));						          tempWord="";						          charIndex++;						          state=1;						          break;						case('['):tempWord+=sourceChar[charIndex];						  		  wordList.add(new Word(tempWord,"LEFT[",line));						          tempWord="";						          charIndex++;						          state=1;						          break;						case(']'):tempWord+=sourceChar[charIndex];						  		  wordList.add(new Word(tempWord,"RIGHT]",line));						          tempWord="";						          charIndex++;						          state=1;						          break;						case('{'):tempWord+=sourceChar[charIndex];						  		  wordList.add(new Word(tempWord,"LEFT{",line));						          tempWord="";						          charIndex++;						          state=1;						          break;						case('}'):tempWord+=sourceChar[charIndex];						  		  wordList.add(new Word(tempWord,"RIGHT}",line));						          tempWord="";						          charIndex++;						          state=1;						          break;						case('<'):state=5;								  tempWord+=sourceChar[charIndex];								  charIndex++;						          break;						case('>'):tempWord+=sourceChar[charIndex];						  		  wordList.add(new Word(tempWord,"LARGER",line));						          tempWord="";						          charIndex++;						          state=1;						          break;						case('='):state=4;								  tempWord+=sourceChar[charIndex];								  charIndex++;								  break;						default:String errorMessage = "Unexpected operator "+sourceChar[charIndex]+" in line:"+line;								errorList.add(errorMessage);								charIndex++;								break;						}					}					break;				}				case(3):				{					int tempState = ((Character.isLetterOrDigit(sourceChar[charIndex])									  ||sourceChar[charIndex]=='_')?3:0);					if(Character.isWhitespace(sourceChar[charIndex])							||Character.isISOControl(sourceChar[charIndex])) tempState=1;					switch(tempState)					{						case(0): 							state=1;							if(isKeyWord(tempWord))							{								wordList.add(new Word(tempWord,keyWord[keyWordIndex],line));							}							else							{								wordList.add(new Word(tempWord,"ID",line));							}							tempWord="";							break;						case(3):							tempWord += sourceChar[charIndex];							charIndex++;							state = 3;							break;						case(1):							if(sourceChar[charIndex-1]=='_')							{								errorList.add("Identifier should not end with '_' in line: "+line);								tempWord="";								if(sourceChar[charIndex]=='\n')line++;								charIndex++;								state=1;								break;							}							else							{								if(isKeyWord(tempWord))								{									wordList.add(new Word(tempWord,keyWord[keyWordIndex],line));								}								else								{									wordList.add(new Word(tempWord,"ID",line));								}								tempWord = "";								if(sourceChar[charIndex]=='\n')line++;								charIndex++;								state=1;								break;							}						default:state=10;					}					break;				}				case(4):				{					if(sourceChar[charIndex]=='=')					{						tempWord+=sourceChar[charIndex];						wordList.add(new Word(tempWord,"EQUAL",line));						tempWord="";						charIndex++;					}					else					{						wordList.add(new Word(tempWord,"ASSIGN",line));						tempWord="";					}					state=1;					break;				}				case(5):				{					if(sourceChar[charIndex]=='>')					{						tempWord+=sourceChar[charIndex];						wordList.add(new Word(tempWord,"NOTEQUAL",line));						tempWord="";						charIndex++;					}					else					{						wordList.add(new Word(tempWord,"LESS",line));						tempWord="";					}					state=1;					break;				}				case(6):				{					if(sourceChar[charIndex]=='+')					{						tempWord+=sourceChar[charIndex];						wordList.add(new Word(tempWord,"AA",line));						tempWord="";						charIndex++;					}					else					{						wordList.add(new Word(tempWord,"ADD",line));						tempWord="";					}					state=1;					break;				}				case(7):				{					if(sourceChar[charIndex]=='-')					{						tempWord+=sourceChar[charIndex];						wordList.add(new Word(tempWord,"MM",line));						tempWord="";						charIndex++;					}					else					{						wordList.add(new Word(tempWord,"MINUS",line));						tempWord="";											}					state=1;					break;				}				case(8):				{					int tempState=(Character.isDigit(sourceChar[charIndex])?1:0);					switch(tempState)					{					case(1):							tempWord+=sourceChar[charIndex];							charIndex++;							state=8;							break;					case(0):							if(Character.isLetter(sourceChar[charIndex]))							{								errorList.add("Identifier should start with a letter in line: "+line);								tempWord="";								state=1;								break;							}							else							{								wordList.add(new Word(tempWord,"NUMBER",line));								tempWord="";								state=1;								break;							}					}					break;				}				case(10):				{					System.out.println("Should start with letter.");					charIndex++;					break;				}			}		}		wordList.add(new Word("","#",0));		return wordList;	}	public ArrayList<String> getErrorList()	{		return errorList;	}}