jdk.nio.CharBuffer — clojure-interop/java.nio 1.0.5

A char buffer.

This class defines four categories of operations upon char buffers:

Absolute and relative get and put methods that read and write single chars;

Relative bulk get methods that transfer contiguous sequences of chars from this buffer into an array; and

Relative bulk put methods that transfer contiguous sequences of chars from a char array, a string, or some other char buffer into this buffer; and

Methods for compacting, duplicating, and slicing a char buffer.

Char buffers can be created either by allocation, which allocates space for the buffer's

content, by wrapping an existing char array or string into a buffer, or by creating a view of an existing byte buffer.

Like a byte buffer, a char buffer is either direct or non-direct. A char buffer created via the wrap methods of this class will be non-direct. A char buffer created as a view of a byte buffer will be direct if, and only if, the byte buffer itself is direct. Whether or not a char buffer is direct may be determined by invoking the isDirect method.

This class implements the CharSequence interface so that character buffers may be used wherever character sequences are accepted, for example in the regular-expression package java.util.regex.

Methods in this class that do not otherwise have a value to return are specified to return the buffer upon which they are invoked. This allows method invocations to be chained.

The sequence of statements

cb.put("text/"); cb.put(subtype); cb.put("; charset="); cb.put(enc);

can, for example, be replaced by the single statement

cb.put("text/").put(subtype).put("; charset=").put(enc);

*allocate clj

(*allocate capacity)

Allocates a new char buffer.

The new buffer's position will be zero, its limit will be its capacity, its mark will be undefined, and each of its elements will be initialized to zero. It will have a backing array, and its array offset will be zero.

capacity - The new buffer's capacity, in chars - int

returns: The new char buffer - java.nio.CharBuffer

throws: java.lang.IllegalArgumentException - If the capacity is a negative integer

*wrap clj

(*wrap array)

(*wrap array offset length)

Wraps a char array into a buffer.

The new buffer will be backed by the given char array; that is, modifications to the buffer will cause the array to be modified and vice versa. The new buffer's capacity will be array.length, its position will be offset, its limit will be offset length, and its mark will be undefined. Its backing array will be the given array, and its array offset will be zero.

array - The array that will back the new buffer - char[] offset - The offset of the subarray to be used; must be non-negative and no larger than array.length. The new buffer's position will be set to this value. - int length - The length of the subarray to be used; must be non-negative and no larger than array.length - offset. The new buffer's limit will be set to offset length. - int

returns: The new char buffer - java.nio.CharBuffer

throws: java.lang.IndexOutOfBoundsException - If the preconditions on the offset and length parameters do not hold

append clj

(append this csq)

(append this csq start end)

Appends a subsequence of the specified character sequence to this buffer (optional operation).

An invocation of this method of the form dst.append(csq, start, end) when csq is not null, behaves in exactly the same way as the invocation

 dst.put(csq.subSequence(start, end).toString())

csq - The character sequence from which a subsequence will be appended. If csq is null, then characters will be appended as if csq contained the four characters "null". - java.lang.CharSequence start - The index of the first character in the subsequence - int end - The index of the character following the last character in the subsequence - int

returns: This buffer - java.nio.CharBuffer

throws: java.nio.BufferOverflowException - If there is insufficient space in this buffer

array clj

(array this)

Returns the char array that backs this buffer (optional operation).

Modifications to this buffer's content will cause the returned array's content to be modified, and vice versa.

Invoke the hasArray method before invoking this method in order to ensure that this buffer has an accessible backing array.

returns: The array that backs this buffer - char[]

throws: java.nio.ReadOnlyBufferException - If this buffer is backed by an array but is read-only

array-offset clj

(array-offset this)

Returns the offset within this buffer's backing array of the first element of the buffer (optional operation).

If this buffer is backed by an array then buffer position p corresponds to array index p arrayOffset().

Invoke the hasArray method before invoking this method in order to ensure that this buffer has an accessible backing array.

returns: The offset within this buffer's array of the first element of the buffer - int

throws: java.nio.ReadOnlyBufferException - If this buffer is backed by an array but is read-only

as-read-only-buffer clj

(as-read-only-buffer this)

Creates a new, read-only char buffer that shares this buffer's content.

The content of the new buffer will be that of this buffer. Changes to this buffer's content will be visible in the new buffer; the new buffer itself, however, will be read-only and will not allow the shared content to be modified. The two buffers' position, limit, and mark values will be independent.

The new buffer's capacity, limit, position, and mark values will be identical to those of this buffer.

If this buffer is itself read-only then this method behaves in exactly the same way as the duplicate method.

returns: The new, read-only char buffer - java.nio.CharBuffer

char-at clj

(char-at this index)

Reads the character at the given index relative to the current position.

index - The index of the character to be read, relative to the position; must be non-negative and smaller than remaining() - int

returns: The character at index position() index - char

throws: java.lang.IndexOutOfBoundsException - If the preconditions on index do not hold

chars clj

(chars this)

Description copied from interface: CharSequence

returns: an IntStream of char values from this sequence - java.util.stream.IntStream

compact clj

(compact this)

Compacts this buffer (optional operation).

The chars between the buffer's current position and its limit, if any, are copied to the beginning of the buffer. That is, the char at index p = position() is copied to index zero, the char at index p 1 is copied to index one, and so forth until the char at index limit() - 1 is copied to index n = limit() - 1 - p. The buffer's position is then set to n+1 and its limit is set to its capacity. The mark, if defined, is discarded.

The buffer's position is set to the number of chars copied, rather than to zero, so that an invocation of this method can be followed immediately by an invocation of another relative put method.

returns: This buffer - java.nio.CharBuffer

throws: java.nio.ReadOnlyBufferException - If this buffer is read-only

compare-to clj

(compare-to this that)

Compares this buffer to another.

Two char buffers are compared by comparing their sequences of remaining elements lexicographically, without regard to the starting position of each sequence within its corresponding buffer.

Pairs of char elements are compared as if by invoking Character.compare(char,char).

A char buffer is not comparable to any other type of object.

that - the object to be compared. - java.nio.CharBuffer

returns: A negative integer, zero, or a positive integer as this buffer is less than, equal to, or greater than the given buffer - int

direct? clj

(direct? this)

Tells whether or not this char buffer is direct.

returns: true if, and only if, this buffer is direct - boolean

duplicate clj

(duplicate this)

Creates a new char buffer that shares this buffer's content.

The content of the new buffer will be that of this buffer. Changes to this buffer's content will be visible in the new buffer, and vice versa; the two buffers' position, limit, and mark values will be independent.

The new buffer's capacity, limit, position, and mark values will be identical to those of this buffer. The new buffer will be direct if, and only if, this buffer is direct, and it will be read-only if, and only if, this buffer is read-only.

returns: The new char buffer - java.nio.CharBuffer

equals clj

(equals this ob)

Tells whether or not this buffer is equal to another object.

Two char buffers are equal if, and only if,

They have the same element type,

They have the same number of remaining elements, and


The two sequences of remaining elements, considered

independently of their starting positions, are pointwise equal.

A char buffer is not equal to any other type of object.

ob - The object to which this buffer is to be compared - java.lang.Object

returns: true if, and only if, this buffer is equal to the given object - boolean

get clj

(get this)

(get this index)

(get this dst offset length)

Relative bulk get method.

This method transfers chars from this buffer into the given destination array. If there are fewer chars remaining in the buffer than are required to satisfy the request, that is, if length > remaining(), then no chars are transferred and a BufferUnderflowException is thrown.

Otherwise, this method copies length chars from this buffer into the given array, starting at the current position of this buffer and at the given offset in the array. The position of this buffer is then incremented by length.

In other words, an invocation of this method of the form src.get(dst, off, len) has exactly the same effect as the loop

 for (int i = off; i < off  len; i++)
     dst[i] = src.get():

except that it first checks that there are sufficient chars in this buffer and it is potentially much more efficient.

dst - The array into which chars are to be written - char[] offset - The offset within the array of the first char to be written; must be non-negative and no larger than dst.length - int length - The maximum number of chars to be written to the given array; must be non-negative and no larger than dst.length - offset - int

returns: This buffer - java.nio.CharBuffer

throws: java.nio.BufferUnderflowException - If there are fewer than length chars remaining in this buffer

has-array? clj

(has-array? this)

Tells whether or not this buffer is backed by an accessible char array.

If this method returns true then the array and arrayOffset methods may safely be invoked.

returns: true if, and only if, this buffer is backed by an array and is not read-only - boolean

hash-code clj

(hash-code this)

Returns the current hash code of this buffer.

The hash code of a char buffer depends only upon its remaining elements; that is, upon the elements from position() up to, and including, the element at limit() - 1.

Because buffer hash codes are content-dependent, it is inadvisable to use buffers as keys in hash maps or similar data structures unless it is known that their contents will not change.

returns: The current hash code of this buffer - int

length clj

(length this)

Returns the length of this character buffer.

When viewed as a character sequence, the length of a character buffer is simply the number of characters between the position (inclusive) and the limit (exclusive); that is, it is equivalent to remaining().

returns: The length of this character buffer - int

order clj

(order this)

Retrieves this buffer's byte order.

The byte order of a char buffer created by allocation or by wrapping an existing char array is the native order of the underlying hardware. The byte order of a char buffer created as a view of a byte buffer is that of the byte buffer at the moment that the view is created.

returns: This buffer's byte order - java.nio.ByteOrder

put clj

(put this c)

(put this index c)

(put this src offset length)

Relative bulk put method (optional operation).

This method transfers chars into this buffer from the given source array. If there are more chars to be copied from the array than remain in this buffer, that is, if length > remaining(), then no chars are transferred and a BufferOverflowException is thrown.

Otherwise, this method copies length chars from the given array into this buffer, starting at the given offset in the array and at the current position of this buffer. The position of this buffer is then incremented by length.

In other words, an invocation of this method of the form dst.put(src, off, len) has exactly the same effect as the loop

 for (int i = off; i < off  len; i++)
     dst.put(a[i]);

except that it first checks that there is sufficient space in this buffer and it is potentially much more efficient.

src - The array from which chars are to be read - char[] offset - The offset within the array of the first char to be read; must be non-negative and no larger than array.length - int length - The number of chars to be read from the given array; must be non-negative and no larger than array.length - offset - int

returns: This buffer - java.nio.CharBuffer

throws: java.nio.BufferOverflowException - If there is insufficient space in this buffer

read clj

(read this target)

Attempts to read characters into the specified character buffer. The buffer is used as a repository of characters as-is: the only changes made are the results of a put operation. No flipping or rewinding of the buffer is performed.

target - the buffer to read characters into - java.nio.CharBuffer

returns: The number of characters added to the buffer, or -1 if this source of characters is at its end - int

throws: java.io.IOException - if an I/O error occurs

slice clj

(slice this)

Creates a new char buffer whose content is a shared subsequence of this buffer's content.

The content of the new buffer will start at this buffer's current position. Changes to this buffer's content will be visible in the new buffer, and vice versa; the two buffers' position, limit, and mark values will be independent.

The new buffer's position will be zero, its capacity and its limit will be the number of chars remaining in this buffer, and its mark will be undefined. The new buffer will be direct if, and only if, this buffer is direct, and it will be read-only if, and only if, this buffer is read-only.

returns: The new char buffer - java.nio.CharBuffer

sub-sequence clj

(sub-sequence this start end)

Creates a new character buffer that represents the specified subsequence of this buffer, relative to the current position.

The new buffer will share this buffer's content; that is, if the content of this buffer is mutable then modifications to one buffer will cause the other to be modified. The new buffer's capacity will be that of this buffer, its position will be position() start, and its limit will be position() end. The new buffer will be direct if, and only if, this buffer is direct, and it will be read-only if, and only if, this buffer is read-only.

start - The index, relative to the current position, of the first character in the subsequence; must be non-negative and no larger than remaining() - int end - The index, relative to the current position, of the character following the last character in the subsequence; must be no smaller than start and no larger than remaining() - int

returns: The new character buffer - java.nio.CharBuffer

throws: java.lang.IndexOutOfBoundsException - If the preconditions on start and end do not hold

to-string clj

(to-string this)

Returns a string containing the characters in this buffer.

The first character of the resulting string will be the character at this buffer's position, while the last character will be the character at index limit() - 1. Invoking this method does not change the buffer's position.

returns: The specified string - java.lang.String