Class FilterReader
- java.lang.Object
-
- java.io.Reader
-
- java.io.FilterReader
- All Implemented Interfaces:
-
Closeable
,AutoCloseable
,Readable
- Direct Known Subclasses:
PushbackReader
public abstract class FilterReader extends Reader
Abstract class for reading filtered character streams. The abstract class FilterReader
itself provides default methods that pass all requests to the contained stream. Subclasses of FilterReader
should override some of these methods and may also provide additional methods and fields.
- Since:
- 1.1
Field Summary
Modifier and Type | Field | Description |
---|---|---|
protected Reader | in | The underlying character-input stream. |
Fields declared in class java.io.Reader
lock
Constructor Summary
Modifier | Constructor | Description |
---|---|---|
protected | FilterReader(Reader in) | Creates a new filtered reader. |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
void | mark(int readAheadLimit) | Marks the present position in the stream. |
boolean | markSupported() | Tells whether this stream supports the mark() operation. |
int | read() | Reads a single character. |
int | read(char[] cbuf,
int off,
int len) | Reads characters into a portion of an array. |
boolean | ready() | Tells whether this stream is ready to be read. |
void | reset() | Resets the stream. |
long | skip(long n) | Skips characters. |
Methods declared in class java.io.Reader
close, nullReader, read, read, transferTo
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Field Detail
in
protected Reader in
The underlying character-input stream.
Constructor Detail
FilterReader
protected FilterReader(Reader in)
Creates a new filtered reader.
- Parameters:
-
in
- a Reader object providing the underlying stream. - Throws:
-
NullPointerException
- ifin
isnull
Method Detail
read
public int read() throws IOException
Reads a single character.
- Overrides:
-
read
in classReader
- Returns:
- The character read, as an integer in the range 0 to 65535 (
0x00-0xffff
), or -1 if the end of the stream has been reached - Throws:
-
IOException
- If an I/O error occurs
read
public int read(char[] cbuf, int off, int len) throws IOException
Reads characters into a portion of an array.
- Specified by:
-
read
in classReader
- Parameters:
-
cbuf
- Destination buffer -
off
- Offset at which to start storing characters -
len
- Maximum number of characters to read - Returns:
- The number of characters read, or -1 if the end of the stream has been reached
- Throws:
-
IOException
- If an I/O error occurs -
IndexOutOfBoundsException
- If an I/O error occurs
skip
public long skip(long n) throws IOException
Skips characters.
- Overrides:
-
skip
in classReader
- Parameters:
-
n
- The number of characters to skip - Returns:
- The number of characters actually skipped
- Throws:
-
IOException
- If an I/O error occurs
ready
public boolean ready() throws IOException
Tells whether this stream is ready to be read.
- Overrides:
-
ready
in classReader
- Returns:
- True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.
- Throws:
-
IOException
- If an I/O error occurs
markSupported
public boolean markSupported()
Tells whether this stream supports the mark() operation.
- Overrides:
-
markSupported
in classReader
- Returns:
- true if and only if this stream supports the mark operation.
mark
public void mark(int readAheadLimit) throws IOException
Marks the present position in the stream.
- Overrides:
-
mark
in classReader
- Parameters:
-
readAheadLimit
- Limit on the number of characters that may be read while still preserving the mark. After reading this many characters, attempting to reset the stream may fail. - Throws:
-
IOException
- If an I/O error occurs
reset
public void reset() throws IOException
Resets the stream.
- Overrides:
-
reset
in classReader
- Throws:
-
IOException
- If an I/O error occurs