ByteArrayInputStream (Java Platform SE 7 ) (original) (raw)
- java.io.InputStream
- java.io.ByteArrayInputStream
All Implemented Interfaces:
Closeable, AutoCloseable
public class ByteArrayInputStream
extends InputStream
A ByteArrayInputStream contains an internal buffer that contains bytes that may be read from the stream. An internal counter keeps track of the next byte to be supplied by the read method.
Closing a ByteArrayInputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.
Since:
JDK1.0
See Also:
StringBufferInputStream
Field Summary
Fields
Modifier and Type Field and Description protected byte[] buf An array of bytes that was provided by the creator of the stream. protected int count The index one greater than the last valid character in the input stream buffer. protected int mark The currently marked position in the stream. protected int pos The index of the next character to read from the input stream buffer. Constructor Summary
Constructors
Constructor and Description ByteArrayInputStream(byte[] buf) Creates a ByteArrayInputStream so that it uses buf as its buffer array. ByteArrayInputStream(byte[] buf, int offset, int length) Creates ByteArrayInputStream that uses buf as its buffer array. Method Summary
Methods
Modifier and Type Method and Description int available() Returns the number of remaining bytes that can be read (or skipped over) from this input stream. void close() Closing a ByteArrayInputStream has no effect. void mark(int readAheadLimit) Set the current marked position in the stream. boolean markSupported() Tests if this InputStream supports mark/reset. int read() Reads the next byte of data from this input stream. int read(byte[] b, int off, int len) Reads up to len bytes of data into an array of bytes from this input stream. void reset() Resets the buffer to the marked position. long skip(long n) Skips n bytes of input from this input stream. * ### Methods inherited from class java.io.[InputStream](../../java/io/InputStream.html "class in java.io") `[read](../../java/io/InputStream.html#read%28byte[]%29)` * ### Methods inherited from class java.lang.[Object](../../java/lang/Object.html "class in java.lang") `[clone](../../java/lang/Object.html#clone%28%29), [equals](../../java/lang/Object.html#equals%28java.lang.Object%29), [finalize](../../java/lang/Object.html#finalize%28%29), [getClass](../../java/lang/Object.html#getClass%28%29), [hashCode](../../java/lang/Object.html#hashCode%28%29), [notify](../../java/lang/Object.html#notify%28%29), [notifyAll](../../java/lang/Object.html#notifyAll%28%29), [toString](../../java/lang/Object.html#toString%28%29), [wait](../../java/lang/Object.html#wait%28%29), [wait](../../java/lang/Object.html#wait%28long%29), [wait](../../java/lang/Object.html#wait%28long,%20int%29)`Field Detail
* #### buf protected byte[] buf An array of bytes that was provided by the creator of the stream. Elements `buf[0]` through `buf[count-1]` are the only bytes that can ever be read from the stream; element `buf[pos]` is the next byte to be read. * #### pos protected int pos The index of the next character to read from the input stream buffer. This value should always be nonnegative and not larger than the value of `count`. The next byte to be read from the input stream buffer will be `buf[pos]`. * #### mark protected int mark The currently marked position in the stream. ByteArrayInputStream objects are marked at position zero by default when constructed. They may be marked at another position within the buffer by the `mark()` method. The current buffer position is set to this point by the`reset()` method. If no mark has been set, then the value of mark is the offset passed to the constructor (or 0 if the offset was not supplied). Since: JDK1.1 * #### count protected int count The index one greater than the last valid character in the input stream buffer. This value should always be nonnegative and not larger than the length of `buf`. It is one greater than the position of the last byte within `buf` that can ever be read from the input stream buffer.Constructor Detail
* #### ByteArrayInputStream public ByteArrayInputStream(byte[] buf) Creates a `ByteArrayInputStream` so that it uses `buf` as its buffer array. The buffer array is not copied. The initial value of `pos` is `0` and the initial value of `count` is the length of`buf`. Parameters: `buf` \- the input buffer. * #### ByteArrayInputStream public ByteArrayInputStream(byte[] buf, int offset, int length) Creates `ByteArrayInputStream` that uses `buf` as its buffer array. The initial value of `pos` is `offset` and the initial value of `count` is the minimum of `offset+length` and `buf.length`. The buffer array is not copied. The buffer's mark is set to the specified offset. Parameters: `buf` \- the input buffer. `offset` \- the offset in the buffer of the first byte to read. `length` \- the maximum number of bytes to read from the buffer.Method Detail
* #### read public int read() 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. This `read` method cannot block. **Specified by:** `[read](../../java/io/InputStream.html#read%28%29)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")` Returns: the next byte of data, or `-1` if the end of the stream has been reached. * #### read public int read(byte[] b, int off, int len) Reads up to `len` bytes of data into an array of bytes from this input stream. If `pos` equals `count`, then `-1` is returned to indicate end of file. Otherwise, the number `k` of bytes read is equal to the smaller of`len` and `count-pos`. If `k` is positive, then bytes`buf[pos]` through `buf[pos+k-1]` are copied into `b[off]` through`b[off+k-1]` in the manner performed by `System.arraycopy`. The value `k` is added into `pos` and `k` is returned. This `read` method cannot block. **Overrides:** `[read](../../java/io/InputStream.html#read%28byte[],%20int,%20int%29)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")` Parameters: `b` \- the buffer into which the data is read. `off` \- the start offset in the destination array `b` `len` \- the maximum number of bytes read. Returns: the total number of bytes read into the buffer, or`-1` if there is no more data because the end of the stream has been reached. Throws: `[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- If `b` is `null`. `[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang")` \- If `off` is negative,`len` is negative, or `len` is greater than`b.length - off` See Also: [InputStream.read()](../../java/io/InputStream.html#read%28%29) * #### skip public long skip(long n) Skips `n` bytes of input from this input stream. Fewer bytes might be skipped if the end of the input stream is reached. The actual number `k` of bytes to be skipped is equal to the smaller of `n` and `count-pos`. The value `k` is added into `pos` and `k` is returned. **Overrides:** `[skip](../../java/io/InputStream.html#skip%28long%29)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")` Parameters: `n` \- the number of bytes to be skipped. Returns: the actual number of bytes skipped. * #### available public int available() Returns the number of remaining bytes that can be read (or skipped over) from this input stream. The value returned is `count - pos`, which is the number of bytes remaining to be read from the input buffer. **Overrides:** `[available](../../java/io/InputStream.html#available%28%29)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")` Returns: the number of remaining bytes that can be read (or skipped over) from this input stream without blocking. * #### markSupported public boolean markSupported() Tests if this `InputStream` supports mark/reset. The`markSupported` method of `ByteArrayInputStream` always returns `true`. **Overrides:** `[markSupported](../../java/io/InputStream.html#markSupported%28%29)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")` Returns: `true` if this stream instance supports the mark and reset methods; `false` otherwise. Since: JDK1.1 See Also: [InputStream.mark(int)](../../java/io/InputStream.html#mark%28int%29), [InputStream.reset()](../../java/io/InputStream.html#reset%28%29) * #### mark public void mark(int readAheadLimit) Set the current marked position in the stream. ByteArrayInputStream objects are marked at position zero by default when constructed. They may be marked at another position within the buffer by this method. If no mark has been set, then the value of the mark is the offset passed to the constructor (or 0 if the offset was not supplied). Note: The `readAheadLimit` for this class has no meaning. **Overrides:** `[mark](../../java/io/InputStream.html#mark%28int%29)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")` Parameters: `readAheadLimit` \- the maximum limit of bytes that can be read before the mark position becomes invalid. Since: JDK1.1 See Also: [InputStream.reset()](../../java/io/InputStream.html#reset%28%29) * #### reset public void reset() Resets the buffer to the marked position. The marked position is 0 unless another position was marked or an offset was specified in the constructor. **Overrides:** `[reset](../../java/io/InputStream.html#reset%28%29)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")` See Also: [InputStream.mark(int)](../../java/io/InputStream.html#mark%28int%29), [IOException](../../java/io/IOException.html "class in java.io") * #### close public void close() throws [IOException](../../java/io/IOException.html "class in java.io") Closing a ByteArrayInputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException . **Specified by:** `[close](../../java/io/Closeable.html#close%28%29)` in interface `[Closeable](../../java/io/Closeable.html "interface in java.io")` **Specified by:** `[close](../../java/lang/AutoCloseable.html#close%28%29)` in interface `[AutoCloseable](../../java/lang/AutoCloseable.html "interface in java.lang")` **Overrides:** `[close](../../java/io/InputStream.html#close%28%29)` in class `[InputStream](../../java/io/InputStream.html "class in java.io")` Throws: `[IOException](../../java/io/IOException.html "class in java.io")` \- if an I/O error occurs.
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