AssetManager.AssetInputStream
public
final
class
AssetManager.AssetInputStream
extends InputStream
java.lang.Object | ||
↳ | java.io.InputStream | |
↳ | android.content.res.AssetManager.AssetInputStream |
Summary
Public methods | |
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int
|
available()
Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, which may be 0, or 0 when end of stream is detected. |
void
|
close()
Closes this input stream and releases any system resources associated with the stream. |
void
|
mark(int readlimit)
Marks the current position in this input stream. |
boolean
|
markSupported()
Tests if this input stream supports the |
int
|
read()
Reads the next byte of data from the input stream. |
int
|
read(byte[] b, int off, int len)
Reads up to |
int
|
read(byte[] b)
Reads some number of bytes from the input stream and stores them into
the buffer array |
void
|
reset()
Repositions this stream to the position at the time the
|
long
|
skip(long n)
Skips over and discards |
Protected methods | |
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void
|
finalize()
Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. |
Inherited methods | |
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Public methods
available
public int available ()
Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, which may be 0, or 0 when end of stream is detected. The read might be on the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.
Note that while some implementations of InputStream
will
return the total number of bytes in the stream, many will not. It is
never correct to use the return value of this method to allocate
a buffer intended to hold all data in this stream.
A subclass's implementation of this method may choose to throw an
IOException
if this input stream has been closed by invoking the
close()
method.
The available
method of InputStream
always returns
0
.
This method should be overridden by subclasses.
Returns | |
---|---|
int |
an estimate of the number of bytes that can be read (or
skipped over) from this input stream without blocking or
0 when it reaches the end of the input stream. |
Throws | |
---|---|
IOException |
close
public void close ()
Closes this input stream and releases any system resources associated with the stream.
The close
method of InputStream
does
nothing.
Throws | |
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IOException |
mark
public void mark (int readlimit)
Marks the current position in this input stream. A subsequent call to
the reset
method repositions this stream at the last marked
position so that subsequent reads re-read the same bytes.
The readlimit
arguments tells this input stream to
allow that many bytes to be read before the mark position gets
invalidated.
The general contract of mark
is that, if the method
markSupported
returns true
, the stream somehow
remembers all the bytes read after the call to mark
and
stands ready to supply those same bytes again if and whenever the method
reset
is called. However, the stream is not required to
remember any data at all if more than readlimit
bytes are
read from the stream before reset
is called.
Marking a closed stream should not have any effect on the stream.
The mark
method of InputStream
does
nothing.
Parameters | |
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readlimit |
int : the maximum limit of bytes that can be read before
the mark position becomes invalid. |
markSupported
public boolean markSupported ()
Tests if this input stream supports the mark
and
reset
methods. Whether or not mark
and
reset
are supported is an invariant property of a
particular input stream instance. The markSupported
method
of InputStream
returns false
.
Returns | |
---|---|
boolean |
true if this stream instance supports the mark
and reset methods; false otherwise. |
read
public int read ()
Reads the next byte of data from the 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 method
blocks until input data is available, the end of the stream is detected,
or an exception is thrown.
A subclass must provide an implementation of this method.
Returns | |
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int |
the next byte of data, or -1 if the end of the
stream is reached. |
Throws | |
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IOException |
read
public int read (byte[] b, int off, int len)
Reads up to len
bytes of data from the input stream into
an array of bytes. An attempt is made to read as many as
len
bytes, but a smaller number may be read.
The number of bytes actually read is returned as an integer.
This method blocks until input data is available, end of file is detected, or an exception is thrown.
If len
is zero, then no bytes are read and
0
is returned; otherwise, there is an attempt to read at
least one byte. If no byte is available because the stream is at end of
file, the value -1
is returned; otherwise, at least one
byte is read and stored into b
.
The first byte read is stored into element b[off]
, the
next one into b[off+1]
, and so on. The number of bytes read
is, at most, equal to len
. Let k be the number of
bytes actually read; these bytes will be stored in elements
b[off]
through b[off+
k-1]
,
leaving elements b[off+
k]
through
b[off+len-1]
unaffected.
In every case, elements b[0]
through
b[off-1]
and elements b[off+len]
through
b[b.length-1]
are unaffected.
The read(b, off, len)
method
for class InputStream
simply calls the method
read()
repeatedly. If the first such call results in an
IOException
, that exception is returned from the call to
the read(b,
off,
len)
method. If
any subsequent call to read()
results in a
IOException
, the exception is caught and treated as if it
were end of file; the bytes read up to that point are stored into
b
and the number of bytes read before the exception
occurred is returned. The default implementation of this method blocks
until the requested amount of input data len
has been read,
end of file is detected, or an exception is thrown. Subclasses are
encouraged to provide a more efficient implementation of this method.
Parameters | |
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b |
byte : This value cannot be null . |
off |
int : the start offset in array b
at which the data is written. |
len |
int : the maximum number of bytes to read. |
Returns | |
---|---|
int |
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 | |
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IOException |
read
public int read (byte[] b)
Reads some number of bytes from the input stream and stores them into
the buffer array b
. The number of bytes actually read is
returned as an integer. This method blocks until input data is
available, end of file is detected, or an exception is thrown.
If the length of b
is zero, then no bytes are read and
0
is returned; otherwise, there is an attempt to read at
least one byte. If no byte is available because the stream is at the
end of the file, the value -1
is returned; otherwise, at
least one byte is read and stored into b
.
The first byte read is stored into element b[0]
, the
next one into b[1]
, and so on. The number of bytes read is,
at most, equal to the length of b
. Let k be the
number of bytes actually read; these bytes will be stored in elements
b[0]
through b[
k-1]
,
leaving elements b[
k]
through
b[b.length-1]
unaffected.
The read(b)
method for class InputStream
has the same effect as:
read(b, 0, b.length)
Parameters | |
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b |
byte : This value cannot be null . |
Returns | |
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int |
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 | |
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IOException |
reset
public void reset ()
Repositions this stream to the position at the time the
mark
method was last called on this input stream.
The general contract of reset
is:
- If the method
markSupported
returnstrue
, then:- If the method
mark
has not been called since the stream was created, or the number of bytes read from the stream sincemark
was last called is larger than the argument tomark
at that last call, then anIOException
might be thrown. - If such an
IOException
is not thrown, then the stream is reset to a state such that all the bytes read since the most recent call tomark
(or since the start of the file, ifmark
has not been called) will be resupplied to subsequent callers of theread
method, followed by any bytes that otherwise would have been the next input data as of the time of the call toreset
.
- If the method
- If the method
markSupported
returnsfalse
, then:- The call to
reset
may throw anIOException
. - If an
IOException
is not thrown, then the stream is reset to a fixed state that depends on the particular type of the input stream and how it was created. The bytes that will be supplied to subsequent callers of theread
method depend on the particular type of the input stream.
- The call to
The method reset
for class InputStream
does nothing except throw an IOException
.
Throws | |
---|---|
IOException |
skip
public long skip (long n)
Skips over and discards n
bytes of data from this input
stream. The skip
method may, for a variety of reasons, end
up skipping over some smaller number of bytes, possibly 0
.
This may result from any of a number of conditions; reaching end of file
before n
bytes have been skipped is only one possibility.
The actual number of bytes skipped is returned. If n
is
negative, the skip
method for class InputStream
always
returns 0, and no bytes are skipped. Subclasses may handle the negative
value differently.
The skip
method implementation of this class creates a
byte array and then repeatedly reads into it until n
bytes
have been read or the end of the stream has been reached. Subclasses are
encouraged to provide a more efficient implementation of this method.
For instance, the implementation may depend on the ability to seek.
Parameters | |
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n |
long : the number of bytes to be skipped. |
Returns | |
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long |
the actual number of bytes skipped which might be zero. |
Throws | |
---|---|
IOException |
Protected methods
finalize
protected void finalize ()
Called by the garbage collector on an object when garbage collection
determines that there are no more references to the object.
A subclass overrides the finalize
method to dispose of
system resources or to perform other cleanup.
The general contract of finalize
is that it is invoked
if and when the Java virtual
machine has determined that there is no longer any
means by which this object can be accessed by any thread that has
not yet died, except as a result of an action taken by the
finalization of some other object or class which is ready to be
finalized. The finalize
method may take any action, including
making this object available again to other threads; the usual purpose
of finalize
, however, is to perform cleanup actions before
the object is irrevocably discarded. For example, the finalize method
for an object that represents an input/output connection might perform
explicit I/O transactions to break the connection before the object is
permanently discarded.
The finalize
method of class Object
performs no
special action; it simply returns normally. Subclasses of
Object
may override this definition.
The Java programming language does not guarantee which thread will
invoke the finalize
method for any given object. It is
guaranteed, however, that the thread that invokes finalize will not
be holding any user-visible synchronization locks when finalize is
invoked. If an uncaught exception is thrown by the finalize method,
the exception is ignored and finalization of that object terminates.
After the finalize
method has been invoked for an object, no
further action is taken until the Java virtual machine has again
determined that there is no longer any means by which this object can
be accessed by any thread that has not yet died, including possible
actions by other objects or classes which are ready to be finalized,
at which point the object may be discarded.
The finalize
method is never invoked more than once by a Java
virtual machine for any given object.
Any exception thrown by the finalize
method causes
the finalization of this object to be halted, but is otherwise
ignored.
Throws | |
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Throwable |