Cijevi u IO pruža vezu između dvije niti koje se izvode u JVM-u u isto vrijeme. Dakle, cijevi se koriste i kao izvor i odredište.
- PipedInputStream je također povezan s PipedOutputStream. Dakle, podaci se mogu pisati pomoću PipedOutputStream i mogu se pisati pomoću PipedInputStream. Ali korištenje obje niti u isto vrijeme stvorit će zastoj za niti.
- Kaže se da je cijev prekinuta ako nit koja je davala bajtove podataka povezanom izlaznom toku više nije živa.
deklaracija: public class PipedInputStream extends InputStream
Konstruktor: | PipedInputStream() : | stvara PipedInputStream da nije povezan.
| PipedInputStream(int pSize) : | stvara PipedInputStream koji nije povezan s navedenom veličinom cijevi.
| PipedInputStream(PipedOutputStream outStream) : | stvara PipedInputStream koji je povezan s PipedOutputStream - 'outStream'.
| PipedInputStream(PipedOutputStream outStream int pSize) : | stvara Piped Input Stream koji je povezan s Piped Output Streamom s navedenom veličinom cijevi. Metode: | int čitanje(): | Reads the next byte of data from this piped input stream.The value byte is returned as an int in the range 0 to 255. This method blocks until input data is available the end of the stream is detected or an exception is thrown. Java // Java program illustrating the working of read() method import java.io.* ; public class NewClass { public static void main ( String [] args ) throws IOException { PipedInputStream geek_input = new PipedInputStream (); PipedOutputStream geek_output = new PipedOutputStream (); try { // Use of connect() : connecting geek_input with geek_output geek_input . connect ( geek_output ); // Use of read() method : geek_output . write ( 71 ); System . out . println ( 'using read() : ' + ( char ) geek_input . read ()); geek_output . write ( 69 ); System . out . println ( 'using read() : ' + ( char ) geek_input . read ()); geek_output . write ( 75 ); System . out . println ( 'using read() : ' + ( char ) geek_input . read ()); } catch ( IOException except ) { except . printStackTrace (); } } } Izlaz: using read() : G using read() : E using read() : K
| read(byte[] buffer int offset int maxlen) : | java.io.PipedInputStream.read(byte[] buffer int offset int maxlen) čita do maxlen bajtova podataka iz Piped Input Stream-a u polje međuspremnika. Metoda se blokira ako se dosegne kraj streama ili se izbaci iznimka. Sintaksa: public int read(byte[] buffer int offset int maxlen) Parameters : buffer : the destination buffer into which the data is to be read offset : starting in the destination array - 'buffer'. maxlen : maximum length of array to be read Return : next 'maxlen' bytes of the data as an integer value return -1 is end of stream is reached Exception : -> IOException : if in case IO error occurs. -> NullPointerException : if buffer is null. -> IndexOutOfBoundsException : if offset is -ve or maxlen is -ve or maxlen > buffer.length - offset.
| primiti (int bajt): | java.io.PipedInputStream.receive(int byte) prima bajt podataka. Ako nijedan unos nije dostupan, metoda se blokira. Sintaksa: protected void receive(int byte) Parameters : byte : the bytes of the data received Return : void Exception : -> IOException : if in case IO error occurs or pipe is broken.
| zatvori() : | java.io.PipedInputStream.close() zatvara Piped Input Stream i oslobađa dodijeljene resurse. Sintaksa: public void close() Parameters : -------------- Return : void Exception : -> IOException : if in case IO error occurs.
| povezivanje (izvor PipedOutputStream) : | java.io.PipedInputStream.connect(izvor PipedOutputStream) povezuje Piped Input Stream s 'source' Piped Output Streamom i u slučaju da je 'source' cijevi s nekim drugim tokom IO iznimka Sintaksa: public void connect(PipedOutputStream source) Parameters : source : the Piped Output Stream to be connected to Return : void Exception : -> IOException : if in case IO error occurs.
| dostupno() : | java.io.PipedInputStream.available() vraća br. bajtova koji se mogu pročitati iz ulaznog toka, a da se zapravo ne blokiraju. Sintaksa: public int available() Parameters : ------------- Return : no. of bytes that can be read from Input Stream without actually being blocked. 0 if the stream is already closed but by invoking close() method Exception : -> IOException : if in case IO error occurs.
Java program koji objašnjava rad metoda klase PipedInputStream: Java // Java program illustrating the working of PipedInputStream // connect() read(byte[] buffer int offset int maxlen) // close() available() import java.io.* ; public class NewClass { public static void main ( String [] args ) throws IOException { PipedInputStream geek_input = new PipedInputStream (); PipedOutputStream geek_output = new PipedOutputStream (); try { // Use of connect() : connecting geek_input with geek_output geek_input . connect ( geek_output ); geek_output . write ( 71 ); geek_output . write ( 69 ); geek_output . write ( 69 ); geek_output . write ( 75 ); geek_output . write ( 83 ); // Use of available() : System . out . println ( 'Use of available() : ' + geek_input . available ()); // Use of read(byte[] buffer int offset int maxlen) : byte [] buffer = new byte [ 5 ] ; // destination 'buffer' geek_input . read ( buffer 0 5 ); String str = new String ( buffer ); System . out . println ( 'Using read(buffer offset maxlen) : ' + str ); // USe of close() method : System . out . println ( 'Closing the stream' ); geek_input . close (); } catch ( IOException except ) { except . printStackTrace (); } } } Izlaz: Use of available() : 5 Using read(buffer offset maxlen) : GEEKS Closing the stream
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