/* * Copyright (C) 2014 The Android Open Source Project * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.lang; import sun.misc.FloatingDecimal; import java.util.Arrays; /** * A mutable sequence of characters. *

* Implements a modifiable string. At any point in time it contains some * particular sequence of characters, but the length and content of the * sequence can be changed through certain method calls. * *

Unless otherwise noted, passing a {@code null} argument to a constructor * or method in this class will cause a {@link NullPointerException} to be * thrown. * * @author Michael McCloskey * @author Martin Buchholz * @author Ulf Zibis * @since 1.5 */ abstract class AbstractStringBuilder implements Appendable, CharSequence { /** * The value is used for character storage. */ char[] value; /** * The count is the number of characters used. */ int count; /** * This no-arg constructor is necessary for serialization of subclasses. */ AbstractStringBuilder() { } /** * Creates an AbstractStringBuilder of the specified capacity. */ AbstractStringBuilder(int capacity) { value = new char[capacity]; } /** * Returns the length (character count). * * @return the length of the sequence of characters currently * represented by this object */ @Override public int length() { return count; } /** * Returns the current capacity. The capacity is the amount of storage * available for newly inserted characters, beyond which an allocation * will occur. * * @return the current capacity */ public int capacity() { return value.length; } /** * Ensures that the capacity is at least equal to the specified minimum. * If the current capacity is less than the argument, then a new internal * array is allocated with greater capacity. The new capacity is the * larger of: *

* If the {@code minimumCapacity} argument is nonpositive, this * method takes no action and simply returns. * Note that subsequent operations on this object can reduce the * actual capacity below that requested here. * * @param minimumCapacity the minimum desired capacity. */ public void ensureCapacity(int minimumCapacity) { if (minimumCapacity > 0) ensureCapacityInternal(minimumCapacity); } /** * For positive values of {@code minimumCapacity}, this method * behaves like {@code ensureCapacity}, however it is never * synchronized. * If {@code minimumCapacity} is non positive due to numeric * overflow, this method throws {@code OutOfMemoryError}. */ private void ensureCapacityInternal(int minimumCapacity) { // overflow-conscious code if (minimumCapacity - value.length > 0) { value = Arrays.copyOf(value, newCapacity(minimumCapacity)); } } /** * The maximum size of array to allocate (unless necessary). * Some VMs reserve some header words in an array. * Attempts to allocate larger arrays may result in * OutOfMemoryError: Requested array size exceeds VM limit */ private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; /** * Returns a capacity at least as large as the given minimum capacity. * Returns the current capacity increased by the same amount + 2 if * that suffices. * Will not return a capacity greater than {@code MAX_ARRAY_SIZE} * unless the given minimum capacity is greater than that. * * @param minCapacity the desired minimum capacity * @throws OutOfMemoryError if minCapacity is less than zero or * greater than Integer.MAX_VALUE */ private int newCapacity(int minCapacity) { // overflow-conscious code int newCapacity = (value.length << 1) + 2; if (newCapacity - minCapacity < 0) { newCapacity = minCapacity; } return (newCapacity <= 0 || MAX_ARRAY_SIZE - newCapacity < 0) ? hugeCapacity(minCapacity) : newCapacity; } private int hugeCapacity(int minCapacity) { if (Integer.MAX_VALUE - minCapacity < 0) { // overflow throw new OutOfMemoryError(); } return (minCapacity > MAX_ARRAY_SIZE) ? minCapacity : MAX_ARRAY_SIZE; } /** * Attempts to reduce storage used for the character sequence. * If the buffer is larger than necessary to hold its current sequence of * characters, then it may be resized to become more space efficient. * Calling this method may, but is not required to, affect the value * returned by a subsequent call to the {@link #capacity()} method. */ public void trimToSize() { if (count < value.length) { value = Arrays.copyOf(value, count); } } /** * Sets the length of the character sequence. * The sequence is changed to a new character sequence * whose length is specified by the argument. For every nonnegative * index k less than {@code newLength}, the character at * index k in the new character sequence is the same as the * character at index k in the old sequence if k is less * than the length of the old character sequence; otherwise, it is the * null character {@code '\u005Cu0000'}. * * In other words, if the {@code newLength} argument is less than * the current length, the length is changed to the specified length. *

* If the {@code newLength} argument is greater than or equal * to the current length, sufficient null characters * ({@code '\u005Cu0000'}) are appended so that * length becomes the {@code newLength} argument. *

* The {@code newLength} argument must be greater than or equal * to {@code 0}. * * @param newLength the new length * @throws IndexOutOfBoundsException if the * {@code newLength} argument is negative. */ public void setLength(int newLength) { if (newLength < 0) throw new StringIndexOutOfBoundsException(newLength); ensureCapacityInternal(newLength); if (count < newLength) { Arrays.fill(value, count, newLength, '\0'); } count = newLength; } /** * Returns the {@code char} value in this sequence at the specified index. * The first {@code char} value is at index {@code 0}, the next at index * {@code 1}, and so on, as in array indexing. *

* The index argument must be greater than or equal to * {@code 0}, and less than the length of this sequence. * *

If the {@code char} value specified by the index is a * surrogate, the surrogate * value is returned. * * @param index the index of the desired {@code char} value. * @return the {@code char} value at the specified index. * @throws IndexOutOfBoundsException if {@code index} is * negative or greater than or equal to {@code length()}. */ @Override public char charAt(int index) { if ((index < 0) || (index >= count)) throw new StringIndexOutOfBoundsException(index); return value[index]; } /** * Returns the character (Unicode code point) at the specified * index. The index refers to {@code char} values * (Unicode code units) and ranges from {@code 0} to * {@link #length()}{@code - 1}. * *

If the {@code char} value specified at the given index * is in the high-surrogate range, the following index is less * than the length of this sequence, and the * {@code char} value at the following index is in the * low-surrogate range, then the supplementary code point * corresponding to this surrogate pair is returned. Otherwise, * the {@code char} value at the given index is returned. * * @param index the index to the {@code char} values * @return the code point value of the character at the * {@code index} * @exception IndexOutOfBoundsException if the {@code index} * argument is negative or not less than the length of this * sequence. */ public int codePointAt(int index) { if ((index < 0) || (index >= count)) { throw new StringIndexOutOfBoundsException(index); } return Character.codePointAtImpl(value, index, count); } /** * Returns the character (Unicode code point) before the specified * index. The index refers to {@code char} values * (Unicode code units) and ranges from {@code 1} to {@link * #length()}. * *

If the {@code char} value at {@code (index - 1)} * is in the low-surrogate range, {@code (index - 2)} is not * negative, and the {@code char} value at {@code (index - * 2)} is in the high-surrogate range, then the * supplementary code point value of the surrogate pair is * returned. If the {@code char} value at {@code index - * 1} is an unpaired low-surrogate or a high-surrogate, the * surrogate value is returned. * * @param index the index following the code point that should be returned * @return the Unicode code point value before the given index. * @exception IndexOutOfBoundsException if the {@code index} * argument is less than 1 or greater than the length * of this sequence. */ public int codePointBefore(int index) { int i = index - 1; if ((i < 0) || (i >= count)) { throw new StringIndexOutOfBoundsException(index); } return Character.codePointBeforeImpl(value, index, 0); } /** * Returns the number of Unicode code points in the specified text * range of this sequence. The text range begins at the specified * {@code beginIndex} and extends to the {@code char} at * index {@code endIndex - 1}. Thus the length (in * {@code char}s) of the text range is * {@code endIndex-beginIndex}. Unpaired surrogates within * this sequence count as one code point each. * * @param beginIndex the index to the first {@code char} of * the text range. * @param endIndex the index after the last {@code char} of * the text range. * @return the number of Unicode code points in the specified text * range * @exception IndexOutOfBoundsException if the * {@code beginIndex} is negative, or {@code endIndex} * is larger than the length of this sequence, or * {@code beginIndex} is larger than {@code endIndex}. */ public int codePointCount(int beginIndex, int endIndex) { if (beginIndex < 0 || endIndex > count || beginIndex > endIndex) { throw new IndexOutOfBoundsException(); } return Character.codePointCountImpl(value, beginIndex, endIndex-beginIndex); } /** * Returns the index within this sequence that is offset from the * given {@code index} by {@code codePointOffset} code * points. Unpaired surrogates within the text range given by * {@code index} and {@code codePointOffset} count as * one code point each. * * @param index the index to be offset * @param codePointOffset the offset in code points * @return the index within this sequence * @exception IndexOutOfBoundsException if {@code index} * is negative or larger then the length of this sequence, * or if {@code codePointOffset} is positive and the subsequence * starting with {@code index} has fewer than * {@code codePointOffset} code points, * or if {@code codePointOffset} is negative and the subsequence * before {@code index} has fewer than the absolute value of * {@code codePointOffset} code points. */ public int offsetByCodePoints(int index, int codePointOffset) { if (index < 0 || index > count) { throw new IndexOutOfBoundsException(); } return Character.offsetByCodePointsImpl(value, 0, count, index, codePointOffset); } /** * Characters are copied from this sequence into the * destination character array {@code dst}. The first character to * be copied is at index {@code srcBegin}; the last character to * be copied is at index {@code srcEnd-1}. The total number of * characters to be copied is {@code srcEnd-srcBegin}. The * characters are copied into the subarray of {@code dst} starting * at index {@code dstBegin} and ending at index: * 

{@code
     * dstbegin + (srcEnd-srcBegin) - 1
     * }
* * @param srcBegin start copying at this offset. * @param srcEnd stop copying at this offset. * @param dst the array to copy the data into. * @param dstBegin offset into {@code dst}. * @throws IndexOutOfBoundsException if any of the following is true: * */ public void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin) { if (srcBegin < 0) throw new StringIndexOutOfBoundsException(srcBegin); if ((srcEnd < 0) || (srcEnd > count)) throw new StringIndexOutOfBoundsException(srcEnd); if (srcBegin > srcEnd) throw new StringIndexOutOfBoundsException("srcBegin > srcEnd"); System.arraycopy(value, srcBegin, dst, dstBegin, srcEnd - srcBegin); } /** * The character at the specified index is set to {@code ch}. This * sequence is altered to represent a new character sequence that is * identical to the old character sequence, except that it contains the * character {@code ch} at position {@code index}. *

* The index argument must be greater than or equal to * {@code 0}, and less than the length of this sequence. * * @param index the index of the character to modify. * @param ch the new character. * @throws IndexOutOfBoundsException if {@code index} is * negative or greater than or equal to {@code length()}. */ public void setCharAt(int index, char ch) { if ((index < 0) || (index >= count)) throw new StringIndexOutOfBoundsException(index); value[index] = ch; } /** * Appends the string representation of the {@code Object} argument. *

* The overall effect is exactly as if the argument were converted * to a string by the method {@link String#valueOf(Object)}, * and the characters of that string were then * {@link #append(String) appended} to this character sequence. * * @param obj an {@code Object}. * @return a reference to this object. * @hide */ public AbstractStringBuilder append(Object obj) { return append(String.valueOf(obj)); } /** * Appends the specified string to this character sequence. *

* The characters of the {@code String} argument are appended, in * order, increasing the length of this sequence by the length of the * argument. If {@code str} is {@code null}, then the four * characters {@code "null"} are appended. *

* Let n be the length of this character sequence just prior to * execution of the {@code append} method. Then the character at * index k in the new character sequence is equal to the character * at index k in the old character sequence, if k is less * than n; otherwise, it is equal to the character at index * k-n in the argument {@code str}. * * @param str a string. * @return a reference to this object. * @hide */ public AbstractStringBuilder append(String str) { if (str == null) return appendNull(); int len = str.length(); ensureCapacityInternal(count + len); str.getChars(0, len, value, count); count += len; return this; } // Documentation in subclasses because of synchro difference /** @hide */ public AbstractStringBuilder append(StringBuffer sb) { if (sb == null) return appendNull(); int len = sb.length(); ensureCapacityInternal(count + len); sb.getChars(0, len, value, count); count += len; return this; } /** * @since 1.8 * @hide */ AbstractStringBuilder append(AbstractStringBuilder asb) { if (asb == null) return appendNull(); int len = asb.length(); ensureCapacityInternal(count + len); asb.getChars(0, len, value, count); count += len; return this; } // Documentation in subclasses because of synchro difference /** @hide */ @Override public AbstractStringBuilder append(CharSequence s) { if (s == null) return appendNull(); if (s instanceof String) return this.append((String)s); if (s instanceof AbstractStringBuilder) return this.append((AbstractStringBuilder)s); return this.append(s, 0, s.length()); } private AbstractStringBuilder appendNull() { int c = count; ensureCapacityInternal(c + 4); final char[] value = this.value; value[c++] = 'n'; value[c++] = 'u'; value[c++] = 'l'; value[c++] = 'l'; count = c; return this; } /** * Appends a subsequence of the specified {@code CharSequence} to this * sequence. *

* Characters of the argument {@code s}, starting at * index {@code start}, are appended, in order, to the contents of * this sequence up to the (exclusive) index {@code end}. The length * of this sequence is increased by the value of {@code end - start}. *

* Let n be the length of this character sequence just prior to * execution of the {@code append} method. Then the character at * index k in this character sequence becomes equal to the * character at index k in this sequence, if k is less than * n; otherwise, it is equal to the character at index * k+start-n in the argument {@code s}. *

* If {@code s} is {@code null}, then this method appends * characters as if the s parameter was a sequence containing the four * characters {@code "null"}. * * @param s the sequence to append. * @param start the starting index of the subsequence to be appended. * @param end the end index of the subsequence to be appended. * @return a reference to this object. * @throws IndexOutOfBoundsException if * {@code start} is negative, or * {@code start} is greater than {@code end} or * {@code end} is greater than {@code s.length()} * @hide */ @Override public AbstractStringBuilder append(CharSequence s, int start, int end) { if (s == null) s = "null"; if ((start < 0) || (start > end) || (end > s.length())) throw new IndexOutOfBoundsException( "start " + start + ", end " + end + ", s.length() " + s.length()); int len = end - start; ensureCapacityInternal(count + len); for (int i = start, j = count; i < end; i++, j++) value[j] = s.charAt(i); count += len; return this; } /** * Appends the string representation of the {@code char} array * argument to this sequence. *

* The characters of the array argument are appended, in order, to * the contents of this sequence. The length of this sequence * increases by the length of the argument. *

* The overall effect is exactly as if the argument were converted * to a string by the method {@link String#valueOf(char[])}, * and the characters of that string were then * {@link #append(String) appended} to this character sequence. * * @param str the characters to be appended. * @return a reference to this object. * @hide */ public AbstractStringBuilder append(char[] str) { int len = str.length; ensureCapacityInternal(count + len); System.arraycopy(str, 0, value, count, len); count += len; return this; } /** * Appends the string representation of a subarray of the * {@code char} array argument to this sequence. *

* Characters of the {@code char} array {@code str}, starting at * index {@code offset}, are appended, in order, to the contents * of this sequence. The length of this sequence increases * by the value of {@code len}. *

* The overall effect is exactly as if the arguments were converted * to a string by the method {@link String#valueOf(char[],int,int)}, * and the characters of that string were then * {@link #append(String) appended} to this character sequence. * * @param str the characters to be appended. * @param offset the index of the first {@code char} to append. * @param len the number of {@code char}s to append. * @return a reference to this object. * @throws IndexOutOfBoundsException * if {@code offset < 0} or {@code len < 0} * or {@code offset+len > str.length} * @hide */ public AbstractStringBuilder append(char str[], int offset, int len) { if (len > 0) // let arraycopy report AIOOBE for len < 0 ensureCapacityInternal(count + len); System.arraycopy(str, offset, value, count, len); count += len; return this; } /** * Appends the string representation of the {@code boolean} * argument to the sequence. *

* The overall effect is exactly as if the argument were converted * to a string by the method {@link String#valueOf(boolean)}, * and the characters of that string were then * {@link #append(String) appended} to this character sequence. * * @param b a {@code boolean}. * @return a reference to this object. * @hide */ public AbstractStringBuilder append(boolean b) { if (b) { ensureCapacityInternal(count + 4); value[count++] = 't'; value[count++] = 'r'; value[count++] = 'u'; value[count++] = 'e'; } else { ensureCapacityInternal(count + 5); value[count++] = 'f'; value[count++] = 'a'; value[count++] = 'l'; value[count++] = 's'; value[count++] = 'e'; } return this; } /** * Appends the string representation of the {@code char} * argument to this sequence. *

* The argument is appended to the contents of this sequence. * The length of this sequence increases by {@code 1}. *

* The overall effect is exactly as if the argument were converted * to a string by the method {@link String#valueOf(char)}, * and the character in that string were then * {@link #append(String) appended} to this character sequence. * * @param c a {@code char}. * @return a reference to this object. * @hide */ @Override public AbstractStringBuilder append(char c) { ensureCapacityInternal(count + 1); value[count++] = c; return this; } /** * Appends the string representation of the {@code int} * argument to this sequence. *

* The overall effect is exactly as if the argument were converted * to a string by the method {@link String#valueOf(int)}, * and the characters of that string were then * {@link #append(String) appended} to this character sequence. * * @param i an {@code int}. * @return a reference to this object. * @hide */ public AbstractStringBuilder append(int i) { if (i == Integer.MIN_VALUE) { append("-2147483648"); return this; } int appendedLength = (i < 0) ? Integer.stringSize(-i) + 1 : Integer.stringSize(i); int spaceNeeded = count + appendedLength; ensureCapacityInternal(spaceNeeded); Integer.getChars(i, spaceNeeded, value); count = spaceNeeded; return this; } /** * Appends the string representation of the {@code long} * argument to this sequence. *

* The overall effect is exactly as if the argument were converted * to a string by the method {@link String#valueOf(long)}, * and the characters of that string were then * {@link #append(String) appended} to this character sequence. * * @param l a {@code long}. * @return a reference to this object. * @hide */ public AbstractStringBuilder append(long l) { if (l == Long.MIN_VALUE) { append("-9223372036854775808"); return this; } int appendedLength = (l < 0) ? Long.stringSize(-l) + 1 : Long.stringSize(l); int spaceNeeded = count + appendedLength; ensureCapacityInternal(spaceNeeded); Long.getChars(l, spaceNeeded, value); count = spaceNeeded; return this; } /** * Appends the string representation of the {@code float} * argument to this sequence. *

* The overall effect is exactly as if the argument were converted * to a string by the method {@link String#valueOf(float)}, * and the characters of that string were then * {@link #append(String) appended} to this character sequence. * * @param f a {@code float}. * @return a reference to this object. * @hide */ public AbstractStringBuilder append(float f) { FloatingDecimal.appendTo(f,this); return this; } /** * Appends the string representation of the {@code double} * argument to this sequence. *

* The overall effect is exactly as if the argument were converted * to a string by the method {@link String#valueOf(double)}, * and the characters of that string were then * {@link #append(String) appended} to this character sequence. * * @param d a {@code double}. * @return a reference to this object. * @hide */ public AbstractStringBuilder append(double d) { FloatingDecimal.appendTo(d,this); return this; } /** * Removes the characters in a substring of this sequence. * The substring begins at the specified {@code start} and extends to * the character at index {@code end - 1} or to the end of the * sequence if no such character exists. If * {@code start} is equal to {@code end}, no changes are made. * * @param start The beginning index, inclusive. * @param end The ending index, exclusive. * @return This object. * @throws StringIndexOutOfBoundsException if {@code start} * is negative, greater than {@code length()}, or * greater than {@code end}. * @hide */ public AbstractStringBuilder delete(int start, int end) { if (start < 0) throw new StringIndexOutOfBoundsException(start); if (end > count) end = count; if (start > end) throw new StringIndexOutOfBoundsException(); int len = end - start; if (len > 0) { System.arraycopy(value, start+len, value, start, count-end); count -= len; } return this; } /** * Appends the string representation of the {@code codePoint} * argument to this sequence. * *

The argument is appended to the contents of this sequence. * The length of this sequence increases by * {@link Character#charCount(int) Character.charCount(codePoint)}. * *

The overall effect is exactly as if the argument were * converted to a {@code char} array by the method * {@link Character#toChars(int)} and the character in that array * were then {@link #append(char[]) appended} to this character * sequence. * * @param codePoint a Unicode code point * @return a reference to this object. * @exception IllegalArgumentException if the specified * {@code codePoint} isn't a valid Unicode code point * @hide */ public AbstractStringBuilder appendCodePoint(int codePoint) { final int count = this.count; if (Character.isBmpCodePoint(codePoint)) { ensureCapacityInternal(count + 1); value[count] = (char) codePoint; this.count = count + 1; } else if (Character.isValidCodePoint(codePoint)) { ensureCapacityInternal(count + 2); Character.toSurrogates(codePoint, value, count); this.count = count + 2; } else { throw new IllegalArgumentException(); } return this; } /** * Removes the {@code char} at the specified position in this * sequence. This sequence is shortened by one {@code char}. * *

Note: If the character at the given index is a supplementary * character, this method does not remove the entire character. If * correct handling of supplementary characters is required, * determine the number of {@code char}s to remove by calling * {@code Character.charCount(thisSequence.codePointAt(index))}, * where {@code thisSequence} is this sequence. * * @param index Index of {@code char} to remove * @return This object. * @throws StringIndexOutOfBoundsException if the {@code index} * is negative or greater than or equal to * {@code length()}. * @hide */ public AbstractStringBuilder deleteCharAt(int index) { if ((index < 0) || (index >= count)) throw new StringIndexOutOfBoundsException(index); System.arraycopy(value, index+1, value, index, count-index-1); count--; return this; } /** * Replaces the characters in a substring of this sequence * with characters in the specified {@code String}. The substring * begins at the specified {@code start} and extends to the character * at index {@code end - 1} or to the end of the * sequence if no such character exists. First the * characters in the substring are removed and then the specified * {@code String} is inserted at {@code start}. (This * sequence will be lengthened to accommodate the * specified String if necessary.) * * @param start The beginning index, inclusive. * @param end The ending index, exclusive. * @param str String that will replace previous contents. * @return This object. * @throws StringIndexOutOfBoundsException if {@code start} * is negative, greater than {@code length()}, or * greater than {@code end}. * @hide */ public AbstractStringBuilder replace(int start, int end, String str) { if (start < 0) throw new StringIndexOutOfBoundsException(start); if (start > count) throw new StringIndexOutOfBoundsException("start > length()"); if (start > end) throw new StringIndexOutOfBoundsException("start > end"); if (end > count) end = count; int len = str.length(); int newCount = count + len - (end - start); ensureCapacityInternal(newCount); System.arraycopy(value, end, value, start + len, count - end); str.getChars(value, start); count = newCount; return this; } /** * Returns a new {@code String} that contains a subsequence of * characters currently contained in this character sequence. The * substring begins at the specified index and extends to the end of * this sequence. * * @param start The beginning index, inclusive. * @return The new string. * @throws StringIndexOutOfBoundsException if {@code start} is * less than zero, or greater than the length of this object. */ public String substring(int start) { return substring(start, count); } /** * Returns a new character sequence that is a subsequence of this sequence. * *

An invocation of this method of the form * * 

{@code
     * sb.subSequence(begin, end)}
* * behaves in exactly the same way as the invocation * * 
{@code
     * sb.substring(begin, end)}
* * This method is provided so that this class can * implement the {@link CharSequence} interface. * * @param start the start index, inclusive. * @param end the end index, exclusive. * @return the specified subsequence. * * @throws IndexOutOfBoundsException * if {@code start} or {@code end} are negative, * if {@code end} is greater than {@code length()}, * or if {@code start} is greater than {@code end} * @spec JSR-51 */ @Override public CharSequence subSequence(int start, int end) { return substring(start, end); } /** * Returns a new {@code String} that contains a subsequence of * characters currently contained in this sequence. The * substring begins at the specified {@code start} and * extends to the character at index {@code end - 1}. * * @param start The beginning index, inclusive. * @param end The ending index, exclusive. * @return The new string. * @throws StringIndexOutOfBoundsException if {@code start} * or {@code end} are negative or greater than * {@code length()}, or {@code start} is * greater than {@code end}. */ public String substring(int start, int end) { if (start < 0) throw new StringIndexOutOfBoundsException(start); if (end > count) throw new StringIndexOutOfBoundsException(end); if (start > end) throw new StringIndexOutOfBoundsException(end - start); return new String(value, start, end - start); } /** * Inserts the string representation of a subarray of the {@code str} * array argument into this sequence. The subarray begins at the * specified {@code offset} and extends {@code len} {@code char}s. * The characters of the subarray are inserted into this sequence at * the position indicated by {@code index}. The length of this * sequence increases by {@code len} {@code char}s. * * @param index position at which to insert subarray. * @param str A {@code char} array. * @param offset the index of the first {@code char} in subarray to * be inserted. * @param len the number of {@code char}s in the subarray to * be inserted. * @return This object * @throws StringIndexOutOfBoundsException if {@code index} * is negative or greater than {@code length()}, or * {@code offset} or {@code len} are negative, or * {@code (offset+len)} is greater than * {@code str.length}. * @hide */ public AbstractStringBuilder insert(int index, char[] str, int offset, int len) { if ((index < 0) || (index > length())) throw new StringIndexOutOfBoundsException(index); if ((offset < 0) || (len < 0) || (offset > str.length - len)) throw new StringIndexOutOfBoundsException( "offset " + offset + ", len " + len + ", str.length " + str.length); ensureCapacityInternal(count + len); System.arraycopy(value, index, value, index + len, count - index); System.arraycopy(str, offset, value, index, len); count += len; return this; } /** * Inserts the string representation of the {@code Object} * argument into this character sequence. *

* The overall effect is exactly as if the second argument were * converted to a string by the method {@link String#valueOf(Object)}, * and the characters of that string were then * {@link #insert(int,String) inserted} into this character * sequence at the indicated offset. *

* The {@code offset} argument must be greater than or equal to * {@code 0}, and less than or equal to the {@linkplain #length() length} * of this sequence. * * @param offset the offset. * @param obj an {@code Object}. * @return a reference to this object. * @throws StringIndexOutOfBoundsException if the offset is invalid. * @hide */ public AbstractStringBuilder insert(int offset, Object obj) { return insert(offset, String.valueOf(obj)); } /** * Inserts the string into this character sequence. *

* The characters of the {@code String} argument are inserted, in * order, into this sequence at the indicated offset, moving up any * characters originally above that position and increasing the length * of this sequence by the length of the argument. If * {@code str} is {@code null}, then the four characters * {@code "null"} are inserted into this sequence. *

* The character at index k in the new character sequence is * equal to: *

* The {@code offset} argument must be greater than or equal to * {@code 0}, and less than or equal to the {@linkplain #length() length} * of this sequence. * * @param offset the offset. * @param str a string. * @return a reference to this object. * @throws StringIndexOutOfBoundsException if the offset is invalid. * @hide */ public AbstractStringBuilder insert(int offset, String str) { if ((offset < 0) || (offset > length())) throw new StringIndexOutOfBoundsException(offset); if (str == null) str = "null"; int len = str.length(); ensureCapacityInternal(count + len); System.arraycopy(value, offset, value, offset + len, count - offset); str.getChars(value, offset); count += len; return this; } /** * Inserts the string representation of the {@code char} array * argument into this sequence. *

* The characters of the array argument are inserted into the * contents of this sequence at the position indicated by * {@code offset}. The length of this sequence increases by * the length of the argument. *

* The overall effect is exactly as if the second argument were * converted to a string by the method {@link String#valueOf(char[])}, * and the characters of that string were then * {@link #insert(int,String) inserted} into this character * sequence at the indicated offset. *

* The {@code offset} argument must be greater than or equal to * {@code 0}, and less than or equal to the {@linkplain #length() length} * of this sequence. * * @param offset the offset. * @param str a character array. * @return a reference to this object. * @throws StringIndexOutOfBoundsException if the offset is invalid. * @hide */ public AbstractStringBuilder insert(int offset, char[] str) { if ((offset < 0) || (offset > length())) throw new StringIndexOutOfBoundsException(offset); int len = str.length; ensureCapacityInternal(count + len); System.arraycopy(value, offset, value, offset + len, count - offset); System.arraycopy(str, 0, value, offset, len); count += len; return this; } /** * Inserts the specified {@code CharSequence} into this sequence. *

* The characters of the {@code CharSequence} argument are inserted, * in order, into this sequence at the indicated offset, moving up * any characters originally above that position and increasing the length * of this sequence by the length of the argument s. *

* The result of this method is exactly the same as if it were an * invocation of this object's * {@link #insert(int,CharSequence,int,int) insert}(dstOffset, s, 0, s.length()) * method. * *

If {@code s} is {@code null}, then the four characters * {@code "null"} are inserted into this sequence. * * @param dstOffset the offset. * @param s the sequence to be inserted * @return a reference to this object. * @throws IndexOutOfBoundsException if the offset is invalid. * @hide */ public AbstractStringBuilder insert(int dstOffset, CharSequence s) { if (s == null) s = "null"; if (s instanceof String) return this.insert(dstOffset, (String)s); return this.insert(dstOffset, s, 0, s.length()); } /** * Inserts a subsequence of the specified {@code CharSequence} into * this sequence. *

* The subsequence of the argument {@code s} specified by * {@code start} and {@code end} are inserted, * in order, into this sequence at the specified destination offset, moving * up any characters originally above that position. The length of this * sequence is increased by {@code end - start}. *

* The character at index k in this sequence becomes equal to: *

* The {@code dstOffset} argument must be greater than or equal to * {@code 0}, and less than or equal to the {@linkplain #length() length} * of this sequence. *

The start argument must be nonnegative, and not greater than * {@code end}. *

The end argument must be greater than or equal to * {@code start}, and less than or equal to the length of s. * *

If {@code s} is {@code null}, then this method inserts * characters as if the s parameter was a sequence containing the four * characters {@code "null"}. * * @param dstOffset the offset in this sequence. * @param s the sequence to be inserted. * @param start the starting index of the subsequence to be inserted. * @param end the end index of the subsequence to be inserted. * @return a reference to this object. * @throws IndexOutOfBoundsException if {@code dstOffset} * is negative or greater than {@code this.length()}, or * {@code start} or {@code end} are negative, or * {@code start} is greater than {@code end} or * {@code end} is greater than {@code s.length()} * @hide */ public AbstractStringBuilder insert(int dstOffset, CharSequence s, int start, int end) { if (s == null) s = "null"; if ((dstOffset < 0) || (dstOffset > this.length())) throw new IndexOutOfBoundsException("dstOffset "+dstOffset); if ((start < 0) || (end < 0) || (start > end) || (end > s.length())) throw new IndexOutOfBoundsException( "start " + start + ", end " + end + ", s.length() " + s.length()); int len = end - start; ensureCapacityInternal(count + len); System.arraycopy(value, dstOffset, value, dstOffset + len, count - dstOffset); for (int i=start; i * The overall effect is exactly as if the second argument were * converted to a string by the method {@link String#valueOf(boolean)}, * and the characters of that string were then * {@link #insert(int,String) inserted} into this character * sequence at the indicated offset. *

* The {@code offset} argument must be greater than or equal to * {@code 0}, and less than or equal to the {@linkplain #length() length} * of this sequence. * * @param offset the offset. * @param b a {@code boolean}. * @return a reference to this object. * @throws StringIndexOutOfBoundsException if the offset is invalid. * @hide */ public AbstractStringBuilder insert(int offset, boolean b) { return insert(offset, String.valueOf(b)); } /** * Inserts the string representation of the {@code char} * argument into this sequence. *

* The overall effect is exactly as if the second argument were * converted to a string by the method {@link String#valueOf(char)}, * and the character in that string were then * {@link #insert(int,String) inserted} into this character * sequence at the indicated offset. *

* The {@code offset} argument must be greater than or equal to * {@code 0}, and less than or equal to the {@linkplain #length() length} * of this sequence. * * @param offset the offset. * @param c a {@code char}. * @return a reference to this object. * @throws IndexOutOfBoundsException if the offset is invalid. * @hide */ public AbstractStringBuilder insert(int offset, char c) { ensureCapacityInternal(count + 1); System.arraycopy(value, offset, value, offset + 1, count - offset); value[offset] = c; count += 1; return this; } /** * Inserts the string representation of the second {@code int} * argument into this sequence. *

* The overall effect is exactly as if the second argument were * converted to a string by the method {@link String#valueOf(int)}, * and the characters of that string were then * {@link #insert(int,String) inserted} into this character * sequence at the indicated offset. *

* The {@code offset} argument must be greater than or equal to * {@code 0}, and less than or equal to the {@linkplain #length() length} * of this sequence. * * @param offset the offset. * @param i an {@code int}. * @return a reference to this object. * @throws StringIndexOutOfBoundsException if the offset is invalid. * @hide */ public AbstractStringBuilder insert(int offset, int i) { return insert(offset, String.valueOf(i)); } /** * Inserts the string representation of the {@code long} * argument into this sequence. *

* The overall effect is exactly as if the second argument were * converted to a string by the method {@link String#valueOf(long)}, * and the characters of that string were then * {@link #insert(int,String) inserted} into this character * sequence at the indicated offset. *

* The {@code offset} argument must be greater than or equal to * {@code 0}, and less than or equal to the {@linkplain #length() length} * of this sequence. * * @param offset the offset. * @param l a {@code long}. * @return a reference to this object. * @throws StringIndexOutOfBoundsException if the offset is invalid. * @hide */ public AbstractStringBuilder insert(int offset, long l) { return insert(offset, String.valueOf(l)); } /** * Inserts the string representation of the {@code float} * argument into this sequence. *

* The overall effect is exactly as if the second argument were * converted to a string by the method {@link String#valueOf(float)}, * and the characters of that string were then * {@link #insert(int,String) inserted} into this character * sequence at the indicated offset. *

* The {@code offset} argument must be greater than or equal to * {@code 0}, and less than or equal to the {@linkplain #length() length} * of this sequence. * * @param offset the offset. * @param f a {@code float}. * @return a reference to this object. * @throws StringIndexOutOfBoundsException if the offset is invalid. * @hide */ public AbstractStringBuilder insert(int offset, float f) { return insert(offset, String.valueOf(f)); } /** * Inserts the string representation of the {@code double} * argument into this sequence. *

* The overall effect is exactly as if the second argument were * converted to a string by the method {@link String#valueOf(double)}, * and the characters of that string were then * {@link #insert(int,String) inserted} into this character * sequence at the indicated offset. *

* The {@code offset} argument must be greater than or equal to * {@code 0}, and less than or equal to the {@linkplain #length() length} * of this sequence. * * @param offset the offset. * @param d a {@code double}. * @return a reference to this object. * @throws StringIndexOutOfBoundsException if the offset is invalid. * @hide */ public AbstractStringBuilder insert(int offset, double d) { return insert(offset, String.valueOf(d)); } /** * Returns the index within this string of the first occurrence of the * specified substring. The integer returned is the smallest value * k such that: * 

{@code
     * this.toString().startsWith(str, k)
     * }
* is {@code true}. * * @param str any string. * @return if the string argument occurs as a substring within this * object, then the index of the first character of the first * such substring is returned; if it does not occur as a * substring, {@code -1} is returned. */ public int indexOf(String str) { return indexOf(str, 0); } /** * Returns the index within this string of the first occurrence of the * specified substring, starting at the specified index. The integer * returned is the smallest value {@code k} for which: * 
{@code
     *     k >= Math.min(fromIndex, this.length()) &&
     *                   this.toString().startsWith(str, k)
     * }
* If no such value of k exists, then -1 is returned. * * @param str the substring for which to search. * @param fromIndex the index from which to start the search. * @return the index within this string of the first occurrence of the * specified substring, starting at the specified index. */ public int indexOf(String str, int fromIndex) { return String.indexOf(value, 0, count, str.toCharArray(), 0, str.length(), fromIndex); } /** * Returns the index within this string of the rightmost occurrence * of the specified substring. The rightmost empty string "" is * considered to occur at the index value {@code this.length()}. * The returned index is the largest value k such that * 
{@code
     * this.toString().startsWith(str, k)
     * }
* is true. * * @param str the substring to search for. * @return if the string argument occurs one or more times as a substring * within this object, then the index of the first character of * the last such substring is returned. If it does not occur as * a substring, {@code -1} is returned. */ public int lastIndexOf(String str) { return lastIndexOf(str, count); } /** * Returns the index within this string of the last occurrence of the * specified substring. The integer returned is the largest value k * such that: * 
{@code
     *     k <= Math.min(fromIndex, this.length()) &&
     *                   this.toString().startsWith(str, k)
     * }
* If no such value of k exists, then -1 is returned. * * @param str the substring to search for. * @param fromIndex the index to start the search from. * @return the index within this sequence of the last occurrence of the * specified substring. */ public int lastIndexOf(String str, int fromIndex) { return String.lastIndexOf(value, 0, count, str.toCharArray(), 0, str.length(), fromIndex); } /** * Causes this character sequence to be replaced by the reverse of * the sequence. If there are any surrogate pairs included in the * sequence, these are treated as single characters for the * reverse operation. Thus, the order of the high-low surrogates * is never reversed. * * Let n be the character length of this character sequence * (not the length in {@code char} values) just prior to * execution of the {@code reverse} method. Then the * character at index k in the new character sequence is * equal to the character at index n-k-1 in the old * character sequence. * *

Note that the reverse operation may result in producing * surrogate pairs that were unpaired low-surrogates and * high-surrogates before the operation. For example, reversing * "\u005CuDC00\u005CuD800" produces "\u005CuD800\u005CuDC00" which is * a valid surrogate pair. * * @return a reference to this object. * @hide */ public AbstractStringBuilder reverse() { boolean hasSurrogates = false; int n = count - 1; for (int j = (n-1) >> 1; j >= 0; j--) { int k = n - j; char cj = value[j]; char ck = value[k]; value[j] = ck; value[k] = cj; if (Character.isSurrogate(cj) || Character.isSurrogate(ck)) { hasSurrogates = true; } } if (hasSurrogates) { reverseAllValidSurrogatePairs(); } return this; } /** Outlined helper method for reverse() */ private void reverseAllValidSurrogatePairs() { for (int i = 0; i < count - 1; i++) { char c2 = value[i]; if (Character.isLowSurrogate(c2)) { char c1 = value[i + 1]; if (Character.isHighSurrogate(c1)) { value[i++] = c1; value[i] = c2; } } } } /** * Returns a string representing the data in this sequence. * A new {@code String} object is allocated and initialized to * contain the character sequence currently represented by this * object. This {@code String} is then returned. Subsequent * changes to this sequence do not affect the contents of the * {@code String}. * * @return a string representation of this sequence of characters. */ @Override public abstract String toString(); /** * Needed by {@code String} for the contentEquals method. */ final char[] getValue() { return value; } }