read(): This method is available in the java.io.PushbackInputStream class of Java.
Syntax:
int java.io.PushbackInputStream.read() throws IOException
This method reads the next byte of data from this input stream.
The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned.
Parameters: NA
Returns: the next byte of data, or -1 if the end of the stream has been reached.
Throws:
1. IOException - if this input stream has been closed by invoking its close() method, or an I/O error occurs.
Approach 1: When no exception
Java
import java.io.IOException;import java.io.InputStream;import java.io.PushbackInputStream;public class PushbackInputStreamread {public static void main(String[] args) throws IOException {InputStream in = new InputStream() {@Overridepublic int read() throws IOException {return 10;}};int size = 10;PushbackInputStream pushbackInputStream =new PushbackInputStream(in, size);System.out.println(pushbackInputStream.read());pushbackInputStream.close();}}
Output:
10
Approach 2: IOException
Java
package com.PushbackInputStream;import java.io.IOException;import java.io.InputStream;import java.io.PushbackInputStream;public class PushbackInputStreamread {public static void main(String[] args) throws IOException {InputStream in = new InputStream() {@Overridepublic int read() throws IOException {return 10;}};int size = 10;PushbackInputStream pushbackInputStream =new PushbackInputStream(in, size);pushbackInputStream.close();System.out.println(pushbackInputStream.read());}}
Output:
Exception in thread "main" java.io.IOException: Stream closed at java.base/java.io.PushbackInputStream.ensureOpen(PushbackInputStream.java:74) at java.base/java.io.PushbackInputStream.read(PushbackInputStream.java:131) at com.PushbackInputStream.PushbackInputStreamread.main(PushbackInputStreamread.java:21)
Some other methods of PushbackInputStream
available(): This method returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking the next invocation of a method for this input stream.
mark(int): This method marks the current position in this input stream.
markSupported(): This method tests if this input stream supports the mark and reset methods, which it does not.
PushbackInputStream(InputStream): This method creates a PushbackInputStream with a 1-byte pushback buffer and saves its argument, the input stream, for later use.
PushbackInputStream(InputStream, int): This method creates a PushbackInputStream with a pushback buffer of the specified size, and saves its argument, the input stream, for later use.
read(): This method reads the next byte of data from this input stream.
read(byte[], int, int): This method reads up to len bytes of data from this input stream into an array of bytes.
reset(): This method repositions this stream to the position at the time the mark method was last called on this input stream.
skip(long): This method skips over and discards n bytes of data from this input stream.
unread(byte[]): This method pushes back an array of bytes by copying it to the front of the pushback buffer.
unread(int): This method pushes back a byte by copying it to the front of the push-back buffer.
unread(byte[], int, int): This method pushes back a portion of an array of bytes by copying it to the front of the pushback buffer.
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