KMP algorithm implemented in Java

/** <Br/> */<br/> package COM. baseframework; </P> <p>/** <br/> * @ author sunyanan KMP <SPAN class = 'wp _ keywordlink '> algorithm </span> <br/> * <br/> */<br/> public class kmpalgorithm {</P> <p>/** <br/> * Next function of the computing mode string <br/> * <br/> * @ Param desstr <br/> * mode string <br/> * @ return mode string's next function, use arrays to save <br/> */<br/> Private Static int [] kmpnext (string desstr) {<br/> int Len = desstr. length (); <br/> int I = 0; <br/> I Nt j =-1; <br/> int next [] = new int [Len]; <br/> while (I <len-1) {<br/> If (j =-1 | (desstr. charat (I) = (desstr. charat (j) {<br/> I ++; <br/> J ++; <br/> If (desstr. charat (I )! = (Desstr. charat (j) {<br/> next [I] = (J + 1 ); <br/>} else {<br/> next [I] = next [J]; <br/>}< br/>} else {<br/> J = (next [J]-1 ); <br/>}< br/> return next; </P> <p >}</P> <p>/** <br/> * KMP core algorithm <br/> * @ Param sourcestr <br/> * @ Param desstr <br/> * @ Param POS <br/> * returns if @ return is successful and matches the first character of the master string. <br/> * location, -1 is returned if a failure occurs. The index starts from 0 <br/> */<br/> Public static int index (string sourcestr, string desstr, int POS) {<br/> int next [] = kmpnext (desstr); <br/> int I = 0; <br/> Int J = 0; <br/> while (I <sourcestr. length ()-1 & J <desstr. length ()-1) {<br/> If (j = 0 | (sourcestr. charat (I) = desstr. charat (j) {<br/> I ++; <br/> J ++; <br/>} else <br/> J = (next [J]-1); <br/>}< br/> If (j> desstr. length ()-2) {<br/> return (I-desstr. length () + 1); <br/>}else <br/> return-1; </P> <p >}< br/>