java.lang.Object
java.io.Reader
java.io.FilterReader
- All Implemented Interfaces:
- Closeable,- AutoCloseable,- Readable
- Direct Known Subclasses:
- PushbackReader
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
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Field SummaryFields
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Constructor SummaryConstructors
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Method SummaryModifier and TypeMethodDescriptionvoidclose()Closes the stream and releases any system resources associated with it.voidmark(int readAheadLimit) Marks the present position in the stream.booleanTells whether this stream supports the mark() operation.intread()Reads a single character.intread(char[] cbuf, int off, int len) Reads characters into a portion of an array.booleanready()Tells whether this stream is ready to be read.voidreset()Resets the stream.longskip(long n) Skips characters.Methods declared in class java.io.ReadernullReader, read, read, transferTo
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Field Details- 
inThe underlying character-input stream.
 
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Constructor Details- 
FilterReaderCreates a new filtered reader.- Parameters:
- in- a Reader object providing the underlying stream.
- Throws:
- NullPointerException- if- inis- null
 
 
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Method Details- 
readReads a single character.- Overrides:
- readin class- Reader
- 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
 
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readReads characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.If lenis zero, then no characters are read and0is returned; otherwise, there is an attempt to read at least one character. If no character is available because the stream is at its end, the value-1is returned; otherwise, at least one character is read and stored intocbuf.- Specified by:
- readin class- Reader
- 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:
- IndexOutOfBoundsException- If- offis negative, or- lenis negative, or- lenis greater than- cbuf.length - off
- IOException- If an I/O error occurs
 
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skipSkips characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached. If the stream is already at its end before this method is invoked, then no characters are skipped and zero is returned.- Overrides:
- skipin class- Reader
- Parameters:
- n- The number of characters to skip
- Returns:
- The number of characters actually skipped
- Throws:
- IllegalArgumentException- If- nis negative and the contained- Reader's- skipmethod throws an IllegalArgumentException for a negative parameter
- IOException- If an I/O error occurs
 
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readyTells whether this stream is ready to be read.- Overrides:
- readyin class- Reader
- 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
 
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markSupportedpublic boolean markSupported()Tells whether this stream supports the mark() operation.- Overrides:
- markSupportedin class- Reader
- Returns:
- true if and only if this stream supports the mark operation.
 
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markMarks the present position in the stream.- Overrides:
- markin class- Reader
- 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
 
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resetResets the stream.- Overrides:
- resetin class- Reader
- Throws:
- IOException- If an I/O error occurs
 
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closeDescription copied from class:ReaderCloses the stream and releases any system resources associated with it. Once the stream has been closed, further read(), ready(), mark(), reset(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect.- Specified by:
- closein interface- AutoCloseable
- Specified by:
- closein interface- Closeable
- Specified by:
- closein class- Reader
- Throws:
- IOException- If an I/O error occurs
 
 
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