Package org.apache.commons.io.input
Class NullInputStream
java.lang.Object
java.io.InputStream
org.apache.commons.io.input.AbstractInputStream
org.apache.commons.io.input.NullInputStream
- All Implemented Interfaces:
Closeable,AutoCloseable
A light weight
InputStream that emulates a stream of a specified size.
This implementation provides a light weight object for testing with an InputStream where the contents don't matter.
One use case would be for testing the handling of large InputStream as it can emulate that scenario without the overhead of actually processing large
numbers of bytes - significantly speeding up test execution times.
This implementation returns zero from the method that reads a byte and leaves the array unchanged in the read methods that are passed a byte array. If
alternative data is required the processByte() and processBytes() methods can be implemented to generate data, for example:
public class TestInputStream extends NullInputStream {
public TestInputStream(int size) {
super(size);
}
protected int processByte() {
return ... // return required value here
}
protected void processBytes(byte[] bytes, int offset, int length) {
for (int i = offset; i < length; i++) {
bytes[i] = ... // set array value here
}
}
}
- Since:
- 1.3
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Field Summary
Fields -
Constructor Summary
ConstructorsConstructorDescriptionConstructs anInputStreamthat emulates a size 0 stream which supports marking and does not throw EOFException.NullInputStream(long size) Constructs anInputStreamthat emulates a specified size which supports marking and does not throw EOFException.NullInputStream(long size, boolean markSupported, boolean throwEofException) Constructs anInputStreamthat emulates a specified size with option settings. -
Method Summary
Modifier and TypeMethodDescriptionintvoidclose()Closes this input stream.longGets the current position.longgetSize()Gets the size thisInputStreamemulates.init()Initializes or re-initializes this instance for reuse.voidmark(int readLimit) Marks the current position.booleanTests whether mark is supported.protected intReturns a byte value for theread()method.protected voidprocessBytes(byte[] bytes, int offset, int length) Processes the bytes for theread(byte[], offset, length)method.intread()Reads a byte.intread(byte[] bytes) Reads some bytes into the specified array.intread(byte[] bytes, int offset, int length) Reads the specified number bytes into an array.voidreset()Resets the stream to the point when mark was last called.longskip(long numberOfBytes) Skips a specified number of bytes.Methods inherited from class org.apache.commons.io.input.AbstractInputStream
isClosed, setClosed
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Field Details
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Constructor Details
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NullInputStream
public NullInputStream()Constructs anInputStreamthat emulates a size 0 stream which supports marking and does not throw EOFException.This is an "empty" input stream.
- Since:
- 2.7
-
NullInputStream
Constructs anInputStreamthat emulates a specified size which supports marking and does not throw EOFException.- Parameters:
size- The size of the input stream to emulate.
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NullInputStream
Constructs anInputStreamthat emulates a specified size with option settings.- Parameters:
size- The size of the input stream to emulate.markSupported- Whether this instance will support themark()functionality.throwEofException- Whether this implementation will throw anEOFExceptionor return -1 when the end of file is reached.
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Method Details
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available
- Overrides:
availablein classInputStream
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close
Closes this input stream.- Specified by:
closein interfaceAutoCloseable- Specified by:
closein interfaceCloseable- Overrides:
closein classAbstractInputStream- Throws:
IOException- If an error occurs.
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getPosition
Gets the current position.- Returns:
- the current position.
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getSize
Gets the size thisInputStreamemulates.- Returns:
- The size of the input stream to emulate.
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init
Initializes or re-initializes this instance for reuse.- Returns:
- this instance.
- Since:
- 2.17.0
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mark
Marks the current position.- Overrides:
markin classInputStream- Parameters:
readLimit- The number of bytes before this marked position is invalid.- Throws:
UnsupportedOperationException- if mark is not supported.
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markSupported
Tests whether mark is supported.- Overrides:
markSupportedin classInputStream- Returns:
- Whether mark is supported or not.
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processByte
Returns a byte value for theread()method.This implementation returns zero.
- Returns:
- This implementation always returns zero.
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processBytes
Processes the bytes for theread(byte[], offset, length)method.This implementation leaves the byte array unchanged.
- Parameters:
bytes- The byte arrayoffset- The offset to start at.length- The number of bytes.
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read
Reads a byte.- Specified by:
readin classInputStream- Returns:
- Either The byte value returned by
processByte()or-1if the end of file has been reached andthrowEofExceptionis set tofalse. - Throws:
EOFException- if the end of file is reached andthrowEofExceptionis set totrue.IOException- if trying to read past the end of file.
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read
Reads some bytes into the specified array.- Overrides:
readin classInputStream- Parameters:
bytes- The byte array to read into- Returns:
- The number of bytes read or
-1if the end of file has been reached andthrowEofExceptionis set tofalse. - Throws:
EOFException- if the end of file is reached andthrowEofExceptionis set totrue.IOException- if trying to read past the end of file.
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read
Reads the specified number bytes into an array.- Overrides:
readin classInputStream- Parameters:
bytes- The byte array to read into.offset- The offset to start reading bytes into.length- The number of bytes to read.- Returns:
- The number of bytes read or
-1if the end of file has been reached andthrowEofExceptionis set tofalse. - Throws:
EOFException- if the end of file is reached andthrowEofExceptionis set totrue.IOException- if trying to read past the end of file.
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reset
Resets the stream to the point when mark was last called.- Overrides:
resetin classInputStream- Throws:
UnsupportedOperationException- if mark is not supported.IOException- If no position has been marked or the read limit has been exceeded since the last position was marked.
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skip
Skips a specified number of bytes.- Overrides:
skipin classInputStream- Parameters:
numberOfBytes- The number of bytes to skip.- Returns:
- The number of bytes skipped or
-1if the end of file has been reached andthrowEofExceptionis set tofalse. - Throws:
EOFException- if the end of file is reached andthrowEofExceptionis set totrue.IOException- if trying to read past the end of file.
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init()to reset state.