Package org.apache.wicket.util.io
Class BOMInputStream
- java.lang.Object
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- java.io.InputStream
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- java.io.FilterInputStream
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- org.apache.wicket.util.io.ProxyInputStream
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- org.apache.wicket.util.io.BOMInputStream
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- All Implemented Interfaces:
Closeable
,AutoCloseable
public class BOMInputStream extends ProxyInputStream
This class is used to wrap a stream that includes an encodedByteOrderMark
as its first bytes. This class detects these bytes and, if required, can automatically skip them and return the subsequent byte as the first byte in the stream. TheByteOrderMark
implementation has the following pre-defined BOMs:- UTF-8 -
ByteOrderMark.UTF_8
- UTF-16BE -
ByteOrderMark.UTF_16LE
- UTF-16LE -
ByteOrderMark.UTF_16BE
- UTF-32BE -
ByteOrderMark.UTF_32LE
- UTF-32LE -
ByteOrderMark.UTF_32BE
Example 1 - Detect and exclude a UTF-8 BOM
BOMInputStream bomIn = new BOMInputStream(in); if (bomIn.hasBOM()) { // has a UTF-8 BOM }
Example 2 - Detect a UTF-8 BOM (but don't exclude it)
boolean include = true; BOMInputStream bomIn = new BOMInputStream(in, include); if (bomIn.hasBOM()) { // has a UTF-8 BOM }
Example 3 - Detect Multiple BOMs
BOMInputStream bomIn = new BOMInputStream(in, ByteOrderMark.UTF_16LE, ByteOrderMark.UTF_16BE, ByteOrderMark.UTF_32LE, ByteOrderMark.UTF_32BE ); if (bomIn.hasBOM() == false) { // No BOM found } else if (bomIn.hasBOM(ByteOrderMark.UTF_16LE)) { // has a UTF-16LE BOM } else if (bomIn.hasBOM(ByteOrderMark.UTF_16BE)) { // has a UTF-16BE BOM } else if (bomIn.hasBOM(ByteOrderMark.UTF_32LE)) { // has a UTF-32LE BOM } else if (bomIn.hasBOM(ByteOrderMark.UTF_32BE)) { // has a UTF-32BE BOM }
- Since:
- 2.0
- Version:
- $Id$
- See Also:
ByteOrderMark
, Wikipedia - Byte Order Mark
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Field Summary
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Fields inherited from class java.io.FilterInputStream
in
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Constructor Summary
Constructors Constructor Description BOMInputStream(InputStream delegate)
Constructs a new BOM InputStream that excludes aByteOrderMark.UTF_8
BOM.BOMInputStream(InputStream delegate, boolean include)
Constructs a new BOM InputStream that detects a aByteOrderMark.UTF_8
and optionally includes it.BOMInputStream(InputStream delegate, boolean include, ByteOrderMark... boms)
Constructs a new BOM InputStream that detects the specified BOMs and optionally includes them.BOMInputStream(InputStream delegate, ByteOrderMark... boms)
Constructs a new BOM InputStream that excludes the specified BOMs.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description ByteOrderMark
getBOM()
Return the BOM (Byte Order Mark).String
getBOMCharsetName()
Return the BOM charset Name -ByteOrderMark.getCharsetName()
.boolean
hasBOM()
Indicates whether the stream contains one of the specified BOMs.boolean
hasBOM(ByteOrderMark bom)
Indicates whether the stream contains the specified BOM.void
mark(int readlimit)
Invokes the delegate'smark(int)
method.int
read()
Invokes the delegate'sread()
method, detecting and optionally skipping BOM.int
read(byte[] buf)
Invokes the delegate'sread(byte[])
method, detecting and optionally skipping BOM.int
read(byte[] buf, int off, int len)
Invokes the delegate'sread(byte[], int, int)
method, detecting and optionally skipping BOM.void
reset()
Invokes the delegate'sreset()
method.long
skip(long n)
Invokes the delegate'sskip(long)
method, detecting and optionallyskipping BOM.-
Methods inherited from class org.apache.wicket.util.io.ProxyInputStream
afterRead, available, beforeRead, close, handleIOException, markSupported
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Methods inherited from class java.io.InputStream
nullInputStream, readAllBytes, readNBytes, readNBytes, transferTo
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Constructor Detail
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BOMInputStream
public BOMInputStream(InputStream delegate)
Constructs a new BOM InputStream that excludes aByteOrderMark.UTF_8
BOM.- Parameters:
delegate
- the InputStream to delegate to
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BOMInputStream
public BOMInputStream(InputStream delegate, boolean include)
Constructs a new BOM InputStream that detects a aByteOrderMark.UTF_8
and optionally includes it.- Parameters:
delegate
- the InputStream to delegate toinclude
- true to include the UTF-8 BOM or false to exclude it
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BOMInputStream
public BOMInputStream(InputStream delegate, ByteOrderMark... boms)
Constructs a new BOM InputStream that excludes the specified BOMs.- Parameters:
delegate
- the InputStream to delegate toboms
- The BOMs to detect and exclude
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BOMInputStream
public BOMInputStream(InputStream delegate, boolean include, ByteOrderMark... boms)
Constructs a new BOM InputStream that detects the specified BOMs and optionally includes them.- Parameters:
delegate
- the InputStream to delegate toinclude
- true to include the specified BOMs or false to exclude themboms
- The BOMs to detect and optionally exclude
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Method Detail
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hasBOM
public boolean hasBOM() throws IOException
Indicates whether the stream contains one of the specified BOMs.- Returns:
- true if the stream has one of the specified BOMs, otherwise false if it does not
- Throws:
IOException
- if an error reading the first bytes of the stream occurs
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hasBOM
public boolean hasBOM(ByteOrderMark bom) throws IOException
Indicates whether the stream contains the specified BOM.- Parameters:
bom
- The BOM to check for- Returns:
- true if the stream has the specified BOM, otherwise false if it does not
- Throws:
IllegalArgumentException
- if the BOM is not one the stream is configured to detectIOException
- if an error reading the first bytes of the stream occurs
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getBOM
public ByteOrderMark getBOM() throws IOException
Return the BOM (Byte Order Mark).- Returns:
- The BOM or null if none
- Throws:
IOException
- if an error reading the first bytes of the stream occurs
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getBOMCharsetName
public String getBOMCharsetName() throws IOException
Return the BOM charset Name -ByteOrderMark.getCharsetName()
.- Returns:
- The BOM charset Name or null if no BOM found
- Throws:
IOException
- if an error reading the first bytes of the stream occurs
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read
public int read() throws IOException
Invokes the delegate'sread()
method, detecting and optionally skipping BOM.- Overrides:
read
in classProxyInputStream
- Returns:
- the byte read (excluding BOM) or -1 if the end of stream
- Throws:
IOException
- if an I/O error occurs
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read
public int read(byte[] buf, int off, int len) throws IOException
Invokes the delegate'sread(byte[], int, int)
method, detecting and optionally skipping BOM.- Overrides:
read
in classProxyInputStream
- Parameters:
buf
- the buffer to read the bytes intooff
- The start offsetlen
- The number of bytes to read (excluding BOM)- Returns:
- the number of bytes read or -1 if the end of stream
- Throws:
IOException
- if an I/O error occurs
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read
public int read(byte[] buf) throws IOException
Invokes the delegate'sread(byte[])
method, detecting and optionally skipping BOM.- Overrides:
read
in classProxyInputStream
- Parameters:
buf
- the buffer to read the bytes into- Returns:
- the number of bytes read (excluding BOM) or -1 if the end of stream
- Throws:
IOException
- if an I/O error occurs
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mark
public void mark(int readlimit)
Invokes the delegate'smark(int)
method.- Overrides:
mark
in classProxyInputStream
- Parameters:
readlimit
- read ahead limit
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reset
public void reset() throws IOException
Invokes the delegate'sreset()
method.- Overrides:
reset
in classProxyInputStream
- Throws:
IOException
- if an I/O error occurs
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skip
public long skip(long n) throws IOException
Invokes the delegate'sskip(long)
method, detecting and optionallyskipping BOM.- Overrides:
skip
in classProxyInputStream
- Parameters:
n
- the number of bytes to skip- Returns:
- the number of bytes to skipped or -1 if the end of stream
- Throws:
IOException
- if an I/O error occurs
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