author | dmarkov |
Wed, 16 Apr 2014 12:51:25 +0400 | |
changeset 24184 | 4da2f6ec4dab |
parent 5506 | 202f599c92aa |
permissions | -rw-r--r-- |
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/* |
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* Copyright (c) 1997, 2008, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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package javax.swing.text; |
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import java.text.CharacterIterator; |
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/** |
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* A segment of a character array representing a fragment |
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* of text. It should be treated as immutable even though |
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* the array is directly accessible. This gives fast access |
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* to fragments of text without the overhead of copying |
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* around characters. This is effectively an unprotected |
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* String. |
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* <p> |
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* The Segment implements the java.text.CharacterIterator |
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* interface to support use with the i18n support without |
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* copying text into a string. |
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* |
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* @author Timothy Prinzing |
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*/ |
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public class Segment implements Cloneable, CharacterIterator, CharSequence { |
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/** |
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* This is the array containing the text of |
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* interest. This array should never be modified; |
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* it is available only for efficiency. |
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*/ |
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public char[] array; |
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/** |
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* This is the offset into the array that |
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* the desired text begins. |
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*/ |
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public int offset; |
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/** |
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* This is the number of array elements that |
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* make up the text of interest. |
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*/ |
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public int count; |
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private boolean partialReturn; |
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/** |
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* Creates a new segment. |
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*/ |
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public Segment() { |
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this(null, 0, 0); |
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} |
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/** |
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* Creates a new segment referring to an existing array. |
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* |
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* @param array the array to refer to |
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* @param offset the offset into the array |
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* @param count the number of characters |
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*/ |
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public Segment(char[] array, int offset, int count) { |
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this.array = array; |
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this.offset = offset; |
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this.count = count; |
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partialReturn = false; |
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} |
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/** |
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* Flag to indicate that partial returns are valid. If the flag is true, |
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* an implementation of the interface method Document.getText(position,length,Segment) |
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* should return as much text as possible without making a copy. The default |
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* state of the flag is false which will cause Document.getText(position,length,Segment) |
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* to provide the same return behavior it always had, which may or may not |
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* make a copy of the text depending upon the request. |
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* |
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* @param p whether or not partial returns are valid. |
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* @since 1.4 |
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*/ |
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public void setPartialReturn(boolean p) { |
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partialReturn = p; |
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} |
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/** |
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* Flag to indicate that partial returns are valid. |
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* |
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* @return whether or not partial returns are valid. |
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* @since 1.4 |
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*/ |
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public boolean isPartialReturn() { |
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return partialReturn; |
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} |
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/** |
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* Converts a segment into a String. |
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* |
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* @return the string |
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*/ |
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public String toString() { |
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if (array != null) { |
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return new String(array, offset, count); |
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} |
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2ae294e4518c
6613529: Avoid duplicate object creation within JDK packages
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changeset
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return ""; |
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} |
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// --- CharacterIterator methods ------------------------------------- |
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/** |
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* Sets the position to getBeginIndex() and returns the character at that |
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* position. |
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* @return the first character in the text, or DONE if the text is empty |
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* @see #getBeginIndex |
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* @since 1.3 |
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*/ |
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public char first() { |
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pos = offset; |
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if (count != 0) { |
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return array[pos]; |
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} |
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return DONE; |
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} |
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/** |
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* Sets the position to getEndIndex()-1 (getEndIndex() if the text is empty) |
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* and returns the character at that position. |
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* @return the last character in the text, or DONE if the text is empty |
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* @see #getEndIndex |
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* @since 1.3 |
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*/ |
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public char last() { |
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pos = offset + count; |
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if (count != 0) { |
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pos -= 1; |
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return array[pos]; |
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} |
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return DONE; |
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} |
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/** |
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* Gets the character at the current position (as returned by getIndex()). |
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* @return the character at the current position or DONE if the current |
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* position is off the end of the text. |
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* @see #getIndex |
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* @since 1.3 |
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*/ |
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public char current() { |
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if (count != 0 && pos < offset + count) { |
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return array[pos]; |
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} |
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return DONE; |
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} |
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/** |
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* Increments the iterator's index by one and returns the character |
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* at the new index. If the resulting index is greater or equal |
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* to getEndIndex(), the current index is reset to getEndIndex() and |
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* a value of DONE is returned. |
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* @return the character at the new position or DONE if the new |
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* position is off the end of the text range. |
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* @since 1.3 |
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*/ |
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public char next() { |
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pos += 1; |
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int end = offset + count; |
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if (pos >= end) { |
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pos = end; |
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return DONE; |
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} |
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return current(); |
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} |
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/** |
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* Decrements the iterator's index by one and returns the character |
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* at the new index. If the current index is getBeginIndex(), the index |
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* remains at getBeginIndex() and a value of DONE is returned. |
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* @return the character at the new position or DONE if the current |
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* position is equal to getBeginIndex(). |
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* @since 1.3 |
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*/ |
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public char previous() { |
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if (pos == offset) { |
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return DONE; |
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} |
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pos -= 1; |
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return current(); |
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} |
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/** |
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* Sets the position to the specified position in the text and returns that |
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* character. |
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* @param position the position within the text. Valid values range from |
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* getBeginIndex() to getEndIndex(). An IllegalArgumentException is thrown |
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* if an invalid value is supplied. |
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* @return the character at the specified position or DONE if the specified position is equal to getEndIndex() |
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* @since 1.3 |
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*/ |
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public char setIndex(int position) { |
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int end = offset + count; |
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if ((position < offset) || (position > end)) { |
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throw new IllegalArgumentException("bad position: " + position); |
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} |
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pos = position; |
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if ((pos != end) && (count != 0)) { |
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return array[pos]; |
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} |
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return DONE; |
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} |
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/** |
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* Returns the start index of the text. |
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* @return the index at which the text begins. |
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* @since 1.3 |
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*/ |
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public int getBeginIndex() { |
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return offset; |
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} |
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/** |
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* Returns the end index of the text. This index is the index of the first |
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* character following the end of the text. |
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* @return the index after the last character in the text |
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* @since 1.3 |
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*/ |
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public int getEndIndex() { |
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return offset + count; |
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} |
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/** |
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* Returns the current index. |
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* @return the current index. |
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* @since 1.3 |
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*/ |
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public int getIndex() { |
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return pos; |
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} |
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// --- CharSequence methods ------------------------------------- |
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/** |
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* {@inheritDoc} |
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* @since 1.6 |
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*/ |
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public char charAt(int index) { |
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if (index < 0 |
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|| index >= count) { |
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throw new StringIndexOutOfBoundsException(index); |
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} |
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return array[offset + index]; |
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} |
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/** |
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* {@inheritDoc} |
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* @since 1.6 |
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*/ |
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public int length() { |
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return count; |
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} |
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/** |
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* {@inheritDoc} |
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* @since 1.6 |
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*/ |
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public CharSequence subSequence(int start, int end) { |
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if (start < 0) { |
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throw new StringIndexOutOfBoundsException(start); |
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} |
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if (end > count) { |
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throw new StringIndexOutOfBoundsException(end); |
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} |
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if (start > end) { |
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throw new StringIndexOutOfBoundsException(end - start); |
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} |
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Segment segment = new Segment(); |
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segment.array = this.array; |
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segment.offset = this.offset + start; |
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segment.count = end - start; |
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return segment; |
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} |
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/** |
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* Creates a shallow copy. |
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* |
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* @return the copy |
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*/ |
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public Object clone() { |
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Object o; |
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try { |
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o = super.clone(); |
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} catch (CloneNotSupportedException cnse) { |
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o = null; |
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} |
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return o; |
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} |
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private int pos; |
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} |