Java : PipedWriter with Examples
Last Modified : June 3, 2023 Published : May 4, 2023
PipedWriter (Java SE 19 & JDK 19) API Examples.
You will find code examples on most PipedWriter methods.
Summary
Piped character-output streams.
try (final var reader = new PipedReader();
final var writer = new PipedWriter(reader)) {
try (final var executor = Executors.newFixedThreadPool(2)) {
executor.submit(() -> {
try (writer) {
writer.write("abc");
TimeUnit.SECONDS.sleep(1);
writer.write('X');
TimeUnit.SECONDS.sleep(1);
writer.write('Y');
TimeUnit.SECONDS.sleep(1);
writer.write('Z');
TimeUnit.SECONDS.sleep(1);
} catch (IOException e) {
System.out.println("Writer IOException! : " + e.getMessage());
} catch (InterruptedException e) {
System.out.println("InterruptedException!");
}
});
executor.submit(() -> {
try (reader) {
System.out.println("-- start --");
while (true) {
final var c = reader.read();
if (c == -1) {
System.out.println("-- end --");
break;
}
System.out.printf("%c%n", c);
}
} catch (IOException e) {
System.out.println("Reader IOException! : " + e.getMessage());
}
});
}
}
// Result
// ↓
//-- start --
//a
//b
//c
//X
//Y
//Z
//-- end --
Fields declared in Writer
Constructors
PipedWriter ()
Creates a piped writer that is not yet connected to a piped reader.
try (final var reader = new PipedReader();
final var writer = new PipedWriter()) {
writer.connect(reader);
try (final var executor = Executors.newFixedThreadPool(2)) {
executor.submit(() -> {
try (writer) {
final var list = List.of('a', 'b', 'c', 'd');
for (final var c : list) {
writer.write(c);
TimeUnit.SECONDS.sleep(1);
}
} catch (IOException e) {
System.out.println("Writer IOException! : " + e.getMessage());
} catch (InterruptedException e) {
System.out.println("InterruptedException!");
}
});
executor.submit(() -> {
try (reader) {
System.out.println("-- start --");
while (true) {
final var c = reader.read();
if (c == -1) {
System.out.println("-- end --");
break;
}
System.out.printf("%c%n", c);
}
} catch (IOException e) {
System.out.println("Reader IOException! : " + e.getMessage());
}
});
}
}
// Result
// ↓
//-- start --
//a
//b
//c
//d
//-- end --
PipedWriter (PipedReader snk)
Creates a piped writer connected to the specified piped reader.
try (final var reader = new PipedReader();
final var writer = new PipedWriter(reader)) {
try (final var executor = Executors.newFixedThreadPool(2)) {
executor.submit(() -> {
try (writer) {
final var list = List.of('a', 'b', 'c', 'd');
for (final var c : list) {
writer.write(c);
TimeUnit.SECONDS.sleep(1);
}
} catch (IOException e) {
System.out.println("Writer IOException! : " + e.getMessage());
} catch (InterruptedException e) {
System.out.println("InterruptedException!");
}
});
executor.submit(() -> {
try (reader) {
System.out.println("-- start --");
while (true) {
final var c = reader.read();
if (c == -1) {
System.out.println("-- end --");
break;
}
System.out.printf("%c%n", c);
}
} catch (IOException e) {
System.out.println("Reader IOException! : " + e.getMessage());
}
});
}
}
// Result
// ↓
//-- start --
//a
//b
//c
//d
//-- end --
Methods
void close ()
Closes this piped output stream and releases any system resources associated with this stream.
try (final var reader = new PipedReader();
final var writer = new PipedWriter(reader)) {
writer.write('a');
System.out.printf("%c%n", reader.read()); // a
}
An example without a try-with-resources statement.
final var writer = new PipedWriter();
try (final var reader = new PipedReader(writer)) {
writer.write('a');
System.out.printf("%c%n", reader.read()); // a
} finally {
writer.close();
}
void connect (PipedReader snk)
Connects this piped writer to a receiver.
Please see PipedWriter().
void flush ()
Flushes this output stream and forces any buffered output characters to be written out.
final long current = System.nanoTime();
final DoubleSupplier elapsedTime = () -> (System.nanoTime() - current) / 1000000000.0;
try (final var reader = new PipedReader();
final var writer = new PipedWriter(reader)) {
try (final var executor = Executors.newFixedThreadPool(2)) {
executor.submit(() -> {
try (writer) {
final var list = List.of('a', 'b', 'c', 'd');
for (final var c : list) {
writer.write(c);
writer.flush();
TimeUnit.SECONDS.sleep(1);
}
} catch (IOException e) {
System.out.println("Writer IOException! : " + e.getMessage());
} catch (InterruptedException e) {
System.out.println("InterruptedException!");
}
});
executor.submit(() -> {
try (reader) {
System.out.println("-- start --");
while (true) {
final var c = reader.read();
if (c == -1) {
System.out.println("-- end --");
break;
}
System.out.printf("%c (%f sec.)%n", c, elapsedTime.getAsDouble());
}
} catch (IOException e) {
System.out.println("Reader IOException! : " + e.getMessage());
}
});
}
}
// Result
// ↓
//-- start --
//a (0.002405 sec.)
//b (1.007973 sec.)
//c (2.018421 sec.)
//d (3.024290 sec.)
//-- end --
void write (char[] cbuf, int off, int len)
Writes len characters from the specified character array starting at offset off to this piped output stream.
try (final var reader = new PipedReader();
final var writer = new PipedWriter(reader)) {
final char[] cbuf = {'a', 'b', 'c'};
{
writer.write(cbuf, 0, 1);
final var a = new char[3];
final var ret = reader.read(a);
// ret = 1 : [a, , ]
System.out.printf("ret = %d : %s%n", ret, Arrays.toString(a));
}
{
writer.write(cbuf, 0, 2);
final var a = new char[3];
final var ret = reader.read(a);
// ret = 2 : [a, b, ]
System.out.printf("ret = %d : %s%n", ret, Arrays.toString(a));
}
{
writer.write(cbuf, 0, 3);
final var a = new char[3];
final var ret = reader.read(a);
// ret = 3 : [a, b, c]
System.out.printf("ret = %d : %s%n", ret, Arrays.toString(a));
}
{
writer.write(cbuf, 1, 2);
final var a = new char[3];
final var ret = reader.read(a);
// ret = 2 : [b, c, ]
System.out.printf("ret = %d : %s%n", ret, Arrays.toString(a));
}
{
writer.write(cbuf, 2, 1);
final var a = new char[3];
final var ret = reader.read(a);
// ret = 1 : [c, , ]
System.out.printf("ret = %d : %s%n", ret, Arrays.toString(a));
}
}
void write (int c)
Writes the specified char to the piped output stream.
Please see PipedWriter(PipedReader snk).
Methods declared in Writer
append, append, append, nullWriter, write, write, write
Please see the link below.
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