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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package java.nio;
import java.io.IOException;
/** A buffer of chars.
* A char buffer can be created in either one of the following ways:
*
* - {@link #allocate(int) Allocate} a new char array and create a buffer based on it;
* - {@link #wrap(char[]) Wrap} an existing char array to create a new buffer;
* - {@link #wrap(CharSequence) Wrap} an existing char sequence to create a new buffer;
* - Use {@link java.nio.ByteBuffer#asCharBuffer() ByteBuffer.asCharBuffer} to create a char
* buffer based on a byte buffer.
*
*/
public abstract class CharBuffer extends Buffer
implements Comparable, CharSequence, Appendable {// , Readable {
// /** Creates a char buffer based on a newly allocated char array.
// *
// * @param capacity the capacity of the new buffer.
// * @return the created char buffer.
// * @throws IllegalArgumentException if {@code capacity} is less than zero.
// */
// public static CharBuffer allocate (int capacity) {
// if (capacity < 0) {
// throw new IllegalArgumentException();
// }
// ByteBuffer bb = ByteBuffer.allocateDirect(capacity * 2);
// bb.order(ByteOrder.nativeOrder());
// return bb.asCharBuffer();
// }
/** Constructs a {@code CharBuffer} with given capacity.
*
* @param capacity the capacity of the buffer.
*/
CharBuffer (int capacity) {
super(capacity);
}
/** Returns the char array which this buffer is based on, if there is one.
*
* @return the char array which this buffer is based on.
* @exception ReadOnlyBufferException if this buffer is based on an array, but it is read-only.
* @exception UnsupportedOperationException if this buffer is not based on an array.
*/
public final char[] array () {
return protectedArray();
}
/** Returns the offset of the char array which this buffer is based on, if there is one.
*
* The offset is the index of the array corresponds to the zero position of the buffer.
*
*
* @return the offset of the char array which this buffer is based on.
* @exception ReadOnlyBufferException if this buffer is based on an array but it is read-only.
* @exception UnsupportedOperationException if this buffer is not based on an array.
*/
public final int arrayOffset () {
return protectedArrayOffset();
}
/** Returns a read-only buffer that shares its content with this buffer.
* The returned buffer is guaranteed to be a new instance, even if this buffer is read-only
* itself. The new buffer's position, limit, capacity and mark are the same as this buffer's.
*
* The new buffer shares its content with this buffer, which means this buffer's change of
* content will be visible to the new buffer. The two buffer's position, limit and mark are
* independent.
*
* @return a read-only version of this buffer.
*/
public abstract CharBuffer asReadOnlyBuffer ();
/** Returns the character located at the specified index in the buffer. The index value is
* referenced from the current buffer position.
*
* @param index the index referenced from the current buffer position. It must not be less than
* zero but less than the value obtained from a call to {@code remaining()}.
* @return the character located at the specified index (referenced from the current position)
* in the buffer.
* @exception IndexOutOfBoundsException if the index is invalid.
*/
public final char charAt (int index) {
if (index < 0 || index >= remaining()) {
throw new IndexOutOfBoundsException();
}
return get(position + index);
}
/** Compacts this char buffer.
* The remaining chars will be moved to the head of the buffer, starting from position
* zero. Then the position is set to {@code remaining()}; the limit is set to capacity; the
* mark is cleared.
*
* @return this buffer.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public abstract CharBuffer compact ();
/** Compare the remaining chars of this buffer to another char buffer's remaining chars.
*
* @param otherBuffer another char buffer.
* @return a negative value if this is less than {@code otherBuffer}; 0 if this equals to
* {@code otherBuffer}; a positive value if this is greater than {@code otherBuffer}.
* @exception ClassCastException if {@code otherBuffer} is not a char buffer.
*/
public int compareTo (CharBuffer otherBuffer) {
int compareRemaining = (remaining() < otherBuffer.remaining()) ?
remaining() : otherBuffer.remaining();
int thisPos = position;
int otherPos = otherBuffer.position;
char thisByte, otherByte;
while (compareRemaining > 0) {
thisByte = get(thisPos);
otherByte = otherBuffer.get(otherPos);
if (thisByte != otherByte) {
return thisByte < otherByte ? -1 : 1;
}
thisPos++;
otherPos++;
compareRemaining--;
}
return remaining() - otherBuffer.remaining();
}
/** Returns a duplicated buffer that shares its content with this buffer.
* The duplicated buffer's initial position, limit, capacity and mark are the same as this
* buffer's. The duplicated buffer's read-only property and byte order are the same as this
* buffer's, too.
* The new buffer shares its content with this buffer, which means either buffer's change
* of content will be visible to the other. The two buffer's position, limit and mark are
* independent.
*
* @return a duplicated buffer that shares its content with this buffer.
*/
public abstract CharBuffer duplicate ();
/** Checks whether this char buffer is equal to another object.
* If {@code other} is not a char buffer then {@code false} is returned. Two char buffers
* are equal if and only if their remaining chars are exactly the same. Position, limit,
* capacity and mark are not considered.
*
* @param other the object to compare with this char buffer.
* @return {@code true} if this char buffer is equal to {@code other}, {@code false} otherwise.
*/
public boolean equals (Object other) {
if (!(other instanceof CharBuffer)) {
return false;
}
CharBuffer otherBuffer = (CharBuffer)other;
if (remaining() != otherBuffer.remaining()) {
return false;
}
int myPosition = position;
int otherPosition = otherBuffer.position;
boolean equalSoFar = true;
while (equalSoFar && (myPosition < limit)) {
equalSoFar = get(myPosition++) == otherBuffer.get(otherPosition++);
}
return equalSoFar;
}
/** Returns the char at the current position and increases the position by 1.
*
* @return the char at the current position.
* @exception BufferUnderflowException if the position is equal or greater than limit.
*/
public abstract char get ();
/** Reads chars from the current position into the specified char array and increases the
* position by the number of chars read.
* Calling this method has the same effect as {@code get(dest, 0, dest.length)}.
*
* @param dest the destination char array.
* @return this buffer.
* @exception BufferUnderflowException if {@code dest.length} is greater than {@code remaining()}.
*/
public CharBuffer get (char[] dest) {
return get(dest, 0, dest.length);
}
/** Reads chars from the current position into the specified char array, starting from the
* specified offset, and increases the position by the number of chars read.
*
* @param dest the target char array.
* @param off the offset of the char array, must not be negative and not greater than {@code
* dest.length}.
* @param len The number of chars to read, must be no less than zero and no greater than {@code
* dest.length - off}.
* @return this buffer.
* @exception IndexOutOfBoundsException if either {@code off} or {@code len} is invalid.
* @exception BufferUnderflowException if {@code len} is greater than {@code remaining()}.
*/
public CharBuffer get (char[] dest, int off, int len) {
int length = dest.length;
if ((off < 0) || (len < 0) || (long)off + (long)len > length) {
throw new IndexOutOfBoundsException();
}
if (len > remaining()) {
throw new BufferUnderflowException();
}
for (int i = off; i < off + len; i++) {
dest[i] = get();
}
return this;
}
/** Returns a char at the specified index; the position is not changed.
*
* @param index the index, must not be negative and less than limit.
* @return a char at the specified index.
* @exception IndexOutOfBoundsException if index is invalid.
*/
public abstract char get (int index);
/** Indicates whether this buffer is based on a char array and is read/write.
*
* @return {@code true} if this buffer is based on a byte array and provides read/write access,
* {@code false} otherwise.
*/
public final boolean hasArray () {
return protectedHasArray();
}
/** Calculates this buffer's hash code from the remaining chars. The position, limit, capacity
* and mark don't affect the hash code.
*
* @return the hash code calculated from the remaining chars.
*/
public int hashCode () {
int myPosition = position;
int hash = 0;
while (myPosition < limit) {
hash = hash + get(myPosition++);
}
return hash;
}
/** Indicates whether this buffer is direct. A direct buffer will try its best to take
* advantage of native memory APIs and it may not stay in the Java heap, so it is not affected
* by garbage collection.
* A char buffer is direct if it is based on a byte buffer and the byte buffer is direct.
*
*
* @return {@code true} if this buffer is direct, {@code false} otherwise.
*/
public abstract boolean isDirect ();
/** Returns the number of remaining chars.
*
* @return the number of remaining chars.
*/
public final int length () {
return remaining();
}
/** Returns the byte order used by this buffer when converting chars from/to bytes.
* If this buffer is not based on a byte buffer, then this always returns the platform's
* native byte order.
*
* @return the byte order used by this buffer when converting chars from/to bytes.
*/
public abstract ByteOrder order ();
/** Child class implements this method to realize {@code array()}.
*
* @see #array() */
abstract char[] protectedArray ();
/** Child class implements this method to realize {@code arrayOffset()}.
*
* @see #arrayOffset() */
abstract int protectedArrayOffset ();
/** Child class implements this method to realize {@code hasArray()}.
*
* @see #hasArray() */
abstract boolean protectedHasArray ();
/** Writes the given char to the current position and increases the position by 1.
*
* @param c the char to write.
* @return this buffer.
* @exception BufferOverflowException if position is equal or greater than limit.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public abstract CharBuffer put (char c);
/** Writes chars from the given char array to the current position and increases the position
* by the number of chars written. Calling this method has the same effect as {@code
* put(src, 0, src.length)}.
*
* @param src the source char array.
* @return this buffer.
* @exception BufferOverflowException if {@code remaining()} is less than {@code src.length}.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public final CharBuffer put (char[] src) {
return put(src, 0, src.length);
}
/** Writes chars from the given char array, starting from the specified offset, to the current
* position and increases the position by the number of chars written.
*
* @param src the source char array.
* @param off the offset of char array, must not be negative and not greater than {@code
* src.length}.
* @param len the number of chars to write, must be no less than zero and no greater than
* {@code src.length - off}.
* @return this buffer.
* @exception BufferOverflowException if {@code remaining()} is less than {@code len}.
* @exception IndexOutOfBoundsException if either {@code off} or {@code len} is invalid.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public CharBuffer put (char[] src, int off, int len) {
int length = src.length;
if ((off < 0) || (len < 0) || (long)off + (long)len > length) {
throw new IndexOutOfBoundsException();
}
if (len > remaining()) {
throw new BufferOverflowException();
}
for (int i = off; i < off + len; i++) {
put(src[i]);
}
return this;
}
/** Writes all the remaining chars of the {@code src} char buffer to this buffer's current
* position, and increases both buffers' position by the number of chars copied.
*
* @param src the source char buffer.
* @return this buffer.
* @exception BufferOverflowException if {@code src.remaining()} is greater than this buffer's
* {@code remaining()}.
* @exception IllegalArgumentException if {@code src} is this buffer.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public CharBuffer put (CharBuffer src) {
if (src == this) {
throw new IllegalArgumentException();
}
if (src.remaining() > remaining()) {
throw new BufferOverflowException();
}
char[] contents = new char[src.remaining()];
src.get(contents);
put(contents);
return this;
}
/** Writes a char to the specified index of this buffer; the position is not changed.
*
* @param index the index, must be no less than zero and less than the limit.
* @param c the char to write.
* @return this buffer.
* @exception IndexOutOfBoundsException if index is invalid.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public abstract CharBuffer put (int index, char c);
/** Writes all chars of the given string to the current position of this buffer, and increases
* the position by the length of string.
* Calling this method has the same effect as {@code put(str, 0, str.length())}.
*
* @param str the string to write.
* @return this buffer.
* @exception BufferOverflowException if {@code remaining()} is less than the length of string.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public final CharBuffer put (String str) {
return put(str, 0, str.length());
}
/** Writes chars of the given string to the current position of this buffer, and increases the
* position by the number of chars written.
*
* @param str the string to write.
* @param start the first char to write, must not be negative and not greater than {@code
* str.length()}.
* @param end the last char to write (excluding), must be less than {@code start} and not
* greater than {@code str.length()}.
* @return this buffer.
* @exception BufferOverflowException if {@code remaining()} is less than {@code end - start}.
* @exception IndexOutOfBoundsException if either {@code start} or {@code end} is invalid.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public CharBuffer put (String str, int start, int end) {
int length = str.length();
if (start < 0 || end < start || end > length) {
throw new IndexOutOfBoundsException();
}
if (end - start > remaining()) {
throw new BufferOverflowException();
}
for (int i = start; i < end; i++) {
put(str.charAt(i));
}
return this;
}
/** Returns a sliced buffer that shares its content with this buffer.
* The sliced buffer's capacity will be this buffer's {@code remaining()}, and its zero
* position will correspond to this buffer's current position. The new buffer's position will
* be 0, limit will be its capacity, and its mark is cleared. The new buffer's read-only
* property and byte order are same as this buffer.
* The new buffer shares its content with this buffer, which means either buffer's change
* of content will be visible to the other. The two buffer's position, limit and mark are
* independent.
*
* @return a sliced buffer that shares its content with this buffer.
*/
public abstract CharBuffer slice ();
/** Returns a new char buffer representing a sub-sequence of this buffer's current remaining
* content.
* The new buffer's position will be {@code position() + start}, limit will be {@code
* position() + end}, capacity will be the same as this buffer. The new buffer's read-only
* property and byte order are the same as this buffer.
* The new buffer shares its content with this buffer, which means either buffer's change
* of content will be visible to the other. The two buffer's position, limit and mark are
* independent.
*
* @param start the start index of the sub-sequence, referenced from the current buffer
* position. Must not be less than zero and not greater than the value obtained from
* a call to {@code remaining()}.
* @param end the end index of the sub-sequence, referenced from the current buffer position.
* Must not be less than {@code start} and not be greater than the value obtained
* from a call to {@code remaining()}.
* @return a new char buffer represents a sub-sequence of this buffer's current remaining
* content.
* @exception IndexOutOfBoundsException if either {@code start} or {@code end} is invalid.
*/
public abstract CharSequence subSequence (int start, int end);
/** Returns a string representing the current remaining chars of this buffer.
*
* @return a string representing the current remaining chars of this buffer.
*/
public String toString () {
StringBuffer strbuf = new StringBuffer();
for (int i = position; i < limit; i++) {
strbuf.append(get(i));
}
return strbuf.toString();
}
/** Writes the given char to the current position and increases the position by 1.
*
* @param c the char to write.
* @return this buffer.
* @exception BufferOverflowException if position is equal or greater than limit.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public CharBuffer append (char c) {
return put(c);
}
/** Writes all chars of the given character sequence {@code csq} to the current position of
* this buffer, and increases the position by the length of the csq.
* Calling this method has the same effect as {@code append(csq.toString())}.
* If the {@code CharSequence} is {@code null} the string "null" will be written to the buffer.
*
* @param csq the {@code CharSequence} to write.
* @return this buffer.
* @exception BufferOverflowException if {@code remaining()} is less than the length of csq.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public CharBuffer append (CharSequence csq) {
if (csq != null) {
return put(csq.toString());
}
return put("null"); //$NON-NLS-1$
}
/** Writes chars of the given {@code CharSequence} to the current position of this buffer, and
* increases the position by the number of chars written.
*
* @param csq the {@code CharSequence} to write.
* @param start the first char to write, must not be negative and not greater than {@code
* csq.length()}.
* @param end the last char to write (excluding), must be less than {@code start} and not
* greater than {@code csq.length()}.
* @return this buffer.
* @exception BufferOverflowException if {@code remaining()} is less than {@code end - start}.
* @exception IndexOutOfBoundsException if either {@code start} or {@code end} is invalid.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public CharBuffer append (CharSequence csq, int start, int end) {
if (csq == null) {
csq = "null"; //$NON-NLS-1$
}
CharSequence cs = csq.subSequence(start, end);
if (cs.length() > 0) {
return put(cs.toString());
}
return this;
}
/** Reads characters from this buffer and puts them into {@code target}. The number of chars
* that are copied is either the number of remaining chars in this buffer or the number of
* remaining chars in {@code target}, whichever is smaller.
*
* @param target the target char buffer.
* @throws IllegalArgumentException if {@code target} is this buffer.
* @throws IOException if an I/O error occurs.
* @throws ReadOnlyBufferException if no changes may be made to the contents of {@code target}.
* @return the number of chars copied or -1 if there are no chars left to be read from this
* buffer.
*/
public int read (CharBuffer target) throws IOException {
if (target == this) {
throw new IllegalArgumentException();
}
if (remaining() == 0) {
return target.remaining() == 0 ? 0 : -1;
}
int result = Math.min(target.remaining(), remaining());
char[] chars = new char[result];
get(chars);
target.put(chars);
return result;
}
}