StringBuilder represents a changeable String.
+ * It provides the operations required to modify the
+ * StringBuilder, including insert, replace, delete, append,
+ * and reverse. It like StringBuffer, but is not
+ * synchronized. It is ideal for use when it is known that the
+ * object will only be used from a single thread.
+ *
+ * StringBuilders are variable-length in nature, so even if
+ * you initialize them to a certain size, they can still grow larger than
+ * that. Capacity indicates the number of characters the
+ * StringBuilder can have in it before it has to grow (growing
+ * the char array is an expensive operation involving new).
+ *
+ *
Incidentally, compilers often implement the String operator "+"
+ * by using a StringBuilder operation:
+ * a + b
+ * is the same as
+ * new StringBuilder().append(a).append(b).toString().
+ *
+ *
Classpath's StringBuilder is capable of sharing memory with Strings for
+ * efficiency. This will help when a StringBuilder is converted to a String
+ * and the StringBuilder is not changed after that (quite common when
+ * performing string concatenation).
+ *
+ * @author Paul Fisher
+ * @author John Keiser
+ * @author Tom Tromey
+ * @author Eric Blake StringBuilder with the specified initial
+ * capacity.
+ *
+ * @param capacity the initial capacity
+ * @throws NegativeArraySizeException if capacity is negative
+ */
+ public StringBuilder(int capacity)
+ {
+ value = new char[capacity];
+ }
+
+ /**
+ * Create a new StringBuilder with the characters in the
+ * specified String. Initial capacity will be the size of the
+ * String plus 16.
+ *
+ * @param str the String to convert
+ * @throws NullPointerException if str is null
+ */
+ public StringBuilder(String str)
+ {
+ // Unfortunately, because the size is 16 larger, we cannot share.
+ count = str.count;
+ value = new char[count + DEFAULT_CAPACITY];
+ str.getChars(0, count, value, 0);
+ }
+
+ /**
+ * Create a new StringBuilder with the characters in the
+ * specified CharSequence. Initial capacity will be the
+ * length of the sequence plus 16; if the sequence reports a length
+ * less than or equal to 0, then the initial capacity will be 16.
+ *
+ * @param seq the initializing CharSequence
+ * @throws NullPointerException if str is null
+ * @since 1.5
+ */
+ public StringBuilder(CharSequence seq)
+ {
+ int len = seq.length();
+ count = len <= 0 ? 0 : len;
+ value = new char[count + DEFAULT_CAPACITY];
+ for (int i = 0; i < len; ++i)
+ value[i] = seq.charAt(i);
+ }
+
+ /**
+ * Get the length of the String this StringBuilder
+ * would create. Not to be confused with the capacity of the
+ * StringBuilder.
+ *
+ * @return the length of this StringBuilder
+ * @see #capacity()
+ * @see #setLength(int)
+ */
+ public int length()
+ {
+ return count;
+ }
+
+ /**
+ * Get the total number of characters this StringBuilder can
+ * support before it must be grown. Not to be confused with length.
+ *
+ * @return the capacity of this StringBuilder
+ * @see #length()
+ * @see #ensureCapacity(int)
+ */
+ public int capacity()
+ {
+ return value.length;
+ }
+
+ /**
+ * Increase the capacity of this StringBuilder. This will
+ * ensure that an expensive growing operation will not occur until
+ * minimumCapacity is reached. The buffer is grown to the
+ * larger of minimumCapacity and
+ * capacity() * 2 + 2, if it is not already large enough.
+ *
+ * @param minimumCapacity the new capacity
+ * @see #capacity()
+ */
+ public void ensureCapacity(int minimumCapacity)
+ {
+ if (minimumCapacity > value.length)
+ {
+ int max = value.length * 2 + 2;
+ minimumCapacity = (minimumCapacity < max ? max : minimumCapacity);
+ char[] nb = new char[minimumCapacity];
+ System.arraycopy(value, 0, nb, 0, count);
+ value = nb;
+ }
+ }
+
+ /**
+ * Set the length of this StringBuilder. If the new length is greater than
+ * the current length, all the new characters are set to '\0'. If the new
+ * length is less than the current length, the first newLength
+ * characters of the old array will be preserved, and the remaining
+ * characters are truncated.
+ *
+ * @param newLength the new length
+ * @throws IndexOutOfBoundsException if the new length is negative
+ * (while unspecified, this is a StringIndexOutOfBoundsException)
+ * @see #length()
+ */
+ public void setLength(int newLength)
+ {
+ if (newLength < 0)
+ throw new StringIndexOutOfBoundsException(newLength);
+
+ int valueLength = value.length;
+
+ /* Always call ensureCapacity in order to preserve copy-on-write
+ semantics. */
+ ensureCapacity(newLength);
+
+ if (newLength < valueLength)
+ {
+ /* If the StringBuilder's value just grew, then we know that
+ value is newly allocated and the region between count and
+ newLength is filled with '\0'. */
+ count = newLength;
+ }
+ else
+ {
+ /* The StringBuilder's value doesn't need to grow. However,
+ we should clear out any cruft that may exist. */
+ while (count < newLength)
+ value[count++] = '\0';
+ }
+ }
+
+ /**
+ * Get the character at the specified index.
+ *
+ * @param index the index of the character to get, starting at 0
+ * @return the character at the specified index
+ * @throws IndexOutOfBoundsException if index is negative or >= length()
+ * (while unspecified, this is a StringIndexOutOfBoundsException)
+ */
+ public char charAt(int index)
+ {
+ if (index < 0 || index >= count)
+ throw new StringIndexOutOfBoundsException(index);
+ return value[index];
+ }
+
+ /**
+ * Get the specified array of characters. srcOffset - srcEnd
+ * characters will be copied into the array you pass in.
+ *
+ * @param srcOffset the index to start copying from (inclusive)
+ * @param srcEnd the index to stop copying from (exclusive)
+ * @param dst the array to copy into
+ * @param dstOffset the index to start copying into
+ * @throws NullPointerException if dst is null
+ * @throws IndexOutOfBoundsException if any source or target indices are
+ * out of range (while unspecified, source problems cause a
+ * StringIndexOutOfBoundsException, and dest problems cause an
+ * ArrayIndexOutOfBoundsException)
+ * @see System#arraycopy(Object, int, Object, int, int)
+ */
+ public void getChars(int srcOffset, int srcEnd,
+ char[] dst, int dstOffset)
+ {
+ if (srcOffset < 0 || srcEnd > count || srcEnd < srcOffset)
+ throw new StringIndexOutOfBoundsException();
+ System.arraycopy(value, srcOffset, dst, dstOffset, srcEnd - srcOffset);
+ }
+
+ /**
+ * Set the character at the specified index.
+ *
+ * @param index the index of the character to set starting at 0
+ * @param ch the value to set that character to
+ * @throws IndexOutOfBoundsException if index is negative or >= length()
+ * (while unspecified, this is a StringIndexOutOfBoundsException)
+ */
+ public void setCharAt(int index, char ch)
+ {
+ if (index < 0 || index >= count)
+ throw new StringIndexOutOfBoundsException(index);
+ // Call ensureCapacity to enforce copy-on-write.
+ ensureCapacity(count);
+ value[index] = ch;
+ }
+
+ /**
+ * Append the String value of the argument to this
+ * StringBuilder. Uses String.valueOf() to convert
+ * to String.
+ *
+ * @param obj the Object to convert and append
+ * @return this StringBuilder
+ * @see String#valueOf(Object)
+ * @see #append(String)
+ */
+ public StringBuilder append(Object obj)
+ {
+ return append(obj == null ? "null" : obj.toString());
+ }
+
+ /**
+ * Append the String to this StringBuilder. If
+ * str is null, the String "null" is appended.
+ *
+ * @param str the String to append
+ * @return this StringBuilder
+ */
+ public StringBuilder append(String str)
+ {
+ if (str == null)
+ str = "null";
+ int len = str.count;
+ ensureCapacity(count + len);
+ str.getChars(0, len, value, count);
+ count += len;
+ return this;
+ }
+
+ /**
+ * Append the StringBuilder value of the argument to this
+ * StringBuilder. This behaves the same as
+ * append((Object) stringBuffer), except it is more efficient.
+ *
+ * @param stringBuffer the StringBuilder to convert and append
+ * @return this StringBuilder
+ * @see #append(Object)
+ * @since 1.4
+ */
+ public StringBuilder append(StringBuffer stringBuffer)
+ {
+ if (stringBuffer == null)
+ return append("null");
+ synchronized (stringBuffer)
+ {
+ int len = stringBuffer.count;
+ ensureCapacity(count + len);
+ System.arraycopy(stringBuffer.value, 0, value, count, len);
+ count += len;
+ }
+ return this;
+ }
+
+ /**
+ * Append the char array to this StringBuilder.
+ * This is similar (but more efficient) than
+ * append(new String(data)), except in the case of null.
+ *
+ * @param data the char[] to append
+ * @return this StringBuilder
+ * @throws NullPointerException if str is null
+ * @see #append(char[], int, int)
+ */
+ public StringBuilder append(char[] data)
+ {
+ return append(data, 0, data.length);
+ }
+
+ /**
+ * Append part of the char array to this
+ * StringBuilder. This is similar (but more efficient) than
+ * append(new String(data, offset, count)), except in the case
+ * of null.
+ *
+ * @param data the char[] to append
+ * @param offset the start location in str
+ * @param count the number of characters to get from str
+ * @return this StringBuilder
+ * @throws NullPointerException if str is null
+ * @throws IndexOutOfBoundsException if offset or count is out of range
+ * (while unspecified, this is a StringIndexOutOfBoundsException)
+ */
+ public StringBuilder append(char[] data, int offset, int count)
+ {
+ if (offset < 0 || count < 0 || offset > data.length - count)
+ throw new StringIndexOutOfBoundsException();
+ ensureCapacity(this.count + count);
+ System.arraycopy(data, offset, value, this.count, count);
+ this.count += count;
+ return this;
+ }
+
+ /**
+ * Append the String value of the argument to this
+ * StringBuilder. Uses String.valueOf() to convert
+ * to String.
+ *
+ * @param bool the boolean to convert and append
+ * @return this StringBuilder
+ * @see String#valueOf(boolean)
+ */
+ public StringBuilder append(boolean bool)
+ {
+ return append(bool ? "true" : "false");
+ }
+
+ /**
+ * Append the char to this StringBuilder.
+ *
+ * @param ch the char to append
+ * @return this StringBuilder
+ */
+ public StringBuilder append(char ch)
+ {
+ ensureCapacity(count + 1);
+ value[count++] = ch;
+ return this;
+ }
+
+ /**
+ * Append the characters in the CharSequence to this
+ * buffer.
+ *
+ * @param seq the CharSequence providing the characters
+ * @return this StringBuilder
+ * @since 1.5
+ */
+ public StringBuilder append(CharSequence seq)
+ {
+ return append(seq, 0, seq.length());
+ }
+
+ /**
+ * Append some characters from the CharSequence to this
+ * buffer. If the argument is null, the four characters "null" are
+ * appended.
+ *
+ * @param seq the CharSequence providing the characters
+ * @param start the starting index
+ * @param end one past the final index
+ * @return this StringBuilder
+ * @since 1.5
+ */
+ public StringBuilder append(CharSequence seq, int start,
+ int end)
+ {
+ if (seq == null)
+ return append("null");
+ if (end - start > 0)
+ {
+ ensureCapacity(count + end - start);
+ for (; start < end; ++start)
+ value[count++] = seq.charAt(start);
+ }
+ return this;
+ }
+
+ /**
+ * Append the String value of the argument to this
+ * StringBuilder. Uses String.valueOf() to convert
+ * to String.
+ *
+ * @param inum the int to convert and append
+ * @return this StringBuilder
+ * @see String#valueOf(int)
+ */
+ // This is native in libgcj, for efficiency.
+ public StringBuilder append(int inum)
+ {
+ return append(String.valueOf(inum));
+ }
+
+ /**
+ * Append the String value of the argument to this
+ * StringBuilder. Uses String.valueOf() to convert
+ * to String.
+ *
+ * @param lnum the long to convert and append
+ * @return this StringBuilder
+ * @see String#valueOf(long)
+ */
+ public StringBuilder append(long lnum)
+ {
+ return append(Long.toString(lnum, 10));
+ }
+
+ /**
+ * Append the String value of the argument to this
+ * StringBuilder. Uses String.valueOf() to convert
+ * to String.
+ *
+ * @param fnum the float to convert and append
+ * @return this StringBuilder
+ * @see String#valueOf(float)
+ */
+ public StringBuilder append(float fnum)
+ {
+ return append(Float.toString(fnum));
+ }
+
+ /**
+ * Append the String value of the argument to this
+ * StringBuilder. Uses String.valueOf() to convert
+ * to String.
+ *
+ * @param dnum the double to convert and append
+ * @return this StringBuilder
+ * @see String#valueOf(double)
+ */
+ public StringBuilder append(double dnum)
+ {
+ return append(Double.toString(dnum));
+ }
+
+ /**
+ * Delete characters from this StringBuilder.
+ * delete(10, 12) will delete 10 and 11, but not 12. It is
+ * harmless for end to be larger than length().
+ *
+ * @param start the first character to delete
+ * @param end the index after the last character to delete
+ * @return this StringBuilder
+ * @throws StringIndexOutOfBoundsException if start or end are out of bounds
+ * @since 1.2
+ */
+ public StringBuilder delete(int start, int end)
+ {
+ if (start < 0 || start > count || start > end)
+ throw new StringIndexOutOfBoundsException(start);
+ if (end > count)
+ end = count;
+ // This will unshare if required.
+ ensureCapacity(count);
+ if (count - end != 0)
+ System.arraycopy(value, end, value, start, count - end);
+ count -= end - start;
+ return this;
+ }
+
+ /**
+ * Delete a character from this StringBuilder.
+ *
+ * @param index the index of the character to delete
+ * @return this StringBuilder
+ * @throws StringIndexOutOfBoundsException if index is out of bounds
+ * @since 1.2
+ */
+ public StringBuilder deleteCharAt(int index)
+ {
+ return delete(index, index + 1);
+ }
+
+ /**
+ * Replace characters between index start (inclusive) and
+ * end (exclusive) with str. If end
+ * is larger than the size of this StringBuilder, all characters after
+ * start are replaced.
+ *
+ * @param start the beginning index of characters to delete (inclusive)
+ * @param end the ending index of characters to delete (exclusive)
+ * @param str the new String to insert
+ * @return this StringBuilder
+ * @throws StringIndexOutOfBoundsException if start or end are out of bounds
+ * @throws NullPointerException if str is null
+ * @since 1.2
+ */
+ public StringBuilder replace(int start, int end, String str)
+ {
+ if (start < 0 || start > count || start > end)
+ throw new StringIndexOutOfBoundsException(start);
+
+ int len = str.count;
+ // Calculate the difference in 'count' after the replace.
+ int delta = len - (end > count ? count : end) + start;
+ ensureCapacity(count + delta);
+
+ if (delta != 0 && end < count)
+ System.arraycopy(value, end, value, end + delta, count - end);
+
+ str.getChars(0, len, value, start);
+ count += delta;
+ return this;
+ }
+
+ /**
+ * Creates a substring of this StringBuilder, starting at a specified index
+ * and ending at the end of this StringBuilder.
+ *
+ * @param beginIndex index to start substring (base 0)
+ * @return new String which is a substring of this StringBuilder
+ * @throws StringIndexOutOfBoundsException if beginIndex is out of bounds
+ * @see #substring(int, int)
+ * @since 1.2
+ */
+ public String substring(int beginIndex)
+ {
+ return substring(beginIndex, count);
+ }
+
+ /**
+ * Creates a substring of this StringBuilder, starting at a specified index
+ * and ending at one character before a specified index. This is implemented
+ * the same as substring(beginIndex, endIndex), to satisfy
+ * the CharSequence interface.
+ *
+ * @param beginIndex index to start at (inclusive, base 0)
+ * @param endIndex index to end at (exclusive)
+ * @return new String which is a substring of this StringBuilder
+ * @throws IndexOutOfBoundsException if beginIndex or endIndex is out of
+ * bounds
+ * @see #substring(int, int)
+ * @since 1.4
+ */
+ public CharSequence subSequence(int beginIndex, int endIndex)
+ {
+ return substring(beginIndex, endIndex);
+ }
+
+ /**
+ * Creates a substring of this StringBuilder, starting at a specified index
+ * and ending at one character before a specified index.
+ *
+ * @param beginIndex index to start at (inclusive, base 0)
+ * @param endIndex index to end at (exclusive)
+ * @return new String which is a substring of this StringBuilder
+ * @throws StringIndexOutOfBoundsException if beginIndex or endIndex is out
+ * of bounds
+ * @since 1.2
+ */
+ public String substring(int beginIndex, int endIndex)
+ {
+ int len = endIndex - beginIndex;
+ if (beginIndex < 0 || endIndex > count || endIndex < beginIndex)
+ throw new StringIndexOutOfBoundsException();
+ if (len == 0)
+ return "";
+ return new String(value, beginIndex, len);
+ }
+
+ /**
+ * Insert a subarray of the char[] argument into this
+ * StringBuilder.
+ *
+ * @param offset the place to insert in this buffer
+ * @param str the char[] to insert
+ * @param str_offset the index in str to start inserting from
+ * @param len the number of characters to insert
+ * @return this StringBuilder
+ * @throws NullPointerException if str is null
+ * @throws StringIndexOutOfBoundsException if any index is out of bounds
+ * @since 1.2
+ */
+ public StringBuilder insert(int offset,
+ char[] str, int str_offset, int len)
+ {
+ if (offset < 0 || offset > count || len < 0
+ || str_offset < 0 || str_offset > str.length - len)
+ throw new StringIndexOutOfBoundsException();
+ ensureCapacity(count + len);
+ System.arraycopy(value, offset, value, offset + len, count - offset);
+ System.arraycopy(str, str_offset, value, offset, len);
+ count += len;
+ return this;
+ }
+
+ /**
+ * Insert the String value of the argument into this
+ * StringBuilder. Uses String.valueOf() to convert
+ * to String.
+ *
+ * @param offset the place to insert in this buffer
+ * @param obj the Object to convert and insert
+ * @return this StringBuilder
+ * @exception StringIndexOutOfBoundsException if offset is out of bounds
+ * @see String#valueOf(Object)
+ */
+ public StringBuilder insert(int offset, Object obj)
+ {
+ return insert(offset, obj == null ? "null" : obj.toString());
+ }
+
+ /**
+ * Insert the String argument into this
+ * StringBuilder. If str is null, the String "null" is used
+ * instead.
+ *
+ * @param offset the place to insert in this buffer
+ * @param str the String to insert
+ * @return this StringBuilder
+ * @throws StringIndexOutOfBoundsException if offset is out of bounds
+ */
+ public StringBuilder insert(int offset, String str)
+ {
+ if (offset < 0 || offset > count)
+ throw new StringIndexOutOfBoundsException(offset);
+ if (str == null)
+ str = "null";
+ int len = str.count;
+ ensureCapacity(count + len);
+ System.arraycopy(value, offset, value, offset + len, count - offset);
+ str.getChars(0, len, value, offset);
+ count += len;
+ return this;
+ }
+
+ /**
+ * Insert the char[] argument into this
+ * StringBuilder.
+ *
+ * @param offset the place to insert in this buffer
+ * @param data the char[] to insert
+ * @return this StringBuilder
+ * @throws NullPointerException if data is null
+ * @throws StringIndexOutOfBoundsException if offset is out of bounds
+ * @see #insert(int, char[], int, int)
+ */
+ public StringBuilder insert(int offset, char[] data)
+ {
+ return insert(offset, data, 0, data.length);
+ }
+
+ /**
+ * Insert the String value of the argument into this
+ * StringBuilder. Uses String.valueOf() to convert
+ * to String.
+ *
+ * @param offset the place to insert in this buffer
+ * @param bool the boolean to convert and insert
+ * @return this StringBuilder
+ * @throws StringIndexOutOfBoundsException if offset is out of bounds
+ * @see String#valueOf(boolean)
+ */
+ public StringBuilder insert(int offset, boolean bool)
+ {
+ return insert(offset, bool ? "true" : "false");
+ }
+
+ /**
+ * Insert the char argument into this StringBuilder.
+ *
+ * @param offset the place to insert in this buffer
+ * @param ch the char to insert
+ * @return this StringBuilder
+ * @throws StringIndexOutOfBoundsException if offset is out of bounds
+ */
+ public StringBuilder insert(int offset, char ch)
+ {
+ if (offset < 0 || offset > count)
+ throw new StringIndexOutOfBoundsException(offset);
+ ensureCapacity(count + 1);
+ System.arraycopy(value, offset, value, offset + 1, count - offset);
+ value[offset] = ch;
+ count++;
+ return this;
+ }
+
+ /**
+ * Insert the String value of the argument into this
+ * StringBuilder. Uses String.valueOf() to convert
+ * to String.
+ *
+ * @param offset the place to insert in this buffer
+ * @param inum the int to convert and insert
+ * @return this StringBuilder
+ * @throws StringIndexOutOfBoundsException if offset is out of bounds
+ * @see String#valueOf(int)
+ */
+ public StringBuilder insert(int offset, int inum)
+ {
+ return insert(offset, String.valueOf(inum));
+ }
+
+ /**
+ * Insert the String value of the argument into this
+ * StringBuilder. Uses String.valueOf() to convert
+ * to String.
+ *
+ * @param offset the place to insert in this buffer
+ * @param lnum the long to convert and insert
+ * @return this StringBuilder
+ * @throws StringIndexOutOfBoundsException if offset is out of bounds
+ * @see String#valueOf(long)
+ */
+ public StringBuilder insert(int offset, long lnum)
+ {
+ return insert(offset, Long.toString(lnum, 10));
+ }
+
+ /**
+ * Insert the String value of the argument into this
+ * StringBuilder. Uses String.valueOf() to convert
+ * to String.
+ *
+ * @param offset the place to insert in this buffer
+ * @param fnum the float to convert and insert
+ * @return this StringBuilder
+ * @throws StringIndexOutOfBoundsException if offset is out of bounds
+ * @see String#valueOf(float)
+ */
+ public StringBuilder insert(int offset, float fnum)
+ {
+ return insert(offset, Float.toString(fnum));
+ }
+
+ /**
+ * Insert the String value of the argument into this
+ * StringBuilder. Uses String.valueOf() to convert
+ * to String.
+ *
+ * @param offset the place to insert in this buffer
+ * @param dnum the double to convert and insert
+ * @return this StringBuilder
+ * @throws StringIndexOutOfBoundsException if offset is out of bounds
+ * @see String#valueOf(double)
+ */
+ public StringBuilder insert(int offset, double dnum)
+ {
+ return insert(offset, Double.toString(dnum));
+ }
+
+ /**
+ * Finds the first instance of a substring in this StringBuilder.
+ *
+ * @param str String to find
+ * @return location (base 0) of the String, or -1 if not found
+ * @throws NullPointerException if str is null
+ * @see #indexOf(String, int)
+ * @since 1.4
+ */
+ public int indexOf(String str)
+ {
+ return indexOf(str, 0);
+ }
+
+ /**
+ * Finds the first instance of a String in this StringBuilder, starting at
+ * a given index. If starting index is less than 0, the search starts at
+ * the beginning of this String. If the starting index is greater than the
+ * length of this String, or the substring is not found, -1 is returned.
+ *
+ * @param str String to find
+ * @param fromIndex index to start the search
+ * @return location (base 0) of the String, or -1 if not found
+ * @throws NullPointerException if str is null
+ * @since 1.4
+ */
+ public int indexOf(String str, int fromIndex)
+ {
+ if (fromIndex < 0)
+ fromIndex = 0;
+ int limit = count - str.count;
+ for ( ; fromIndex <= limit; fromIndex++)
+ if (regionMatches(fromIndex, str))
+ return fromIndex;
+ return -1;
+ }
+
+ /**
+ * Finds the last instance of a substring in this StringBuilder.
+ *
+ * @param str String to find
+ * @return location (base 0) of the String, or -1 if not found
+ * @throws NullPointerException if str is null
+ * @see #lastIndexOf(String, int)
+ * @since 1.4
+ */
+ public int lastIndexOf(String str)
+ {
+ return lastIndexOf(str, count - str.count);
+ }
+
+ /**
+ * Finds the last instance of a String in this StringBuilder, starting at a
+ * given index. If starting index is greater than the maximum valid index,
+ * then the search begins at the end of this String. If the starting index
+ * is less than zero, or the substring is not found, -1 is returned.
+ *
+ * @param str String to find
+ * @param fromIndex index to start the search
+ * @return location (base 0) of the String, or -1 if not found
+ * @throws NullPointerException if str is null
+ * @since 1.4
+ */
+ public int lastIndexOf(String str, int fromIndex)
+ {
+ fromIndex = Math.min(fromIndex, count - str.count);
+ for ( ; fromIndex >= 0; fromIndex--)
+ if (regionMatches(fromIndex, str))
+ return fromIndex;
+ return -1;
+ }
+
+ /**
+ * Reverse the characters in this StringBuilder. The same sequence of
+ * characters exists, but in the reverse index ordering.
+ *
+ * @return this StringBuilder
+ */
+ public StringBuilder reverse()
+ {
+ // Call ensureCapacity to enforce copy-on-write.
+ ensureCapacity(count);
+ for (int i = count >> 1, j = count - i; --i >= 0; ++j)
+ {
+ char c = value[i];
+ value[i] = value[j];
+ value[j] = c;
+ }
+ return this;
+ }
+
+ /**
+ * Convert this StringBuilder to a String. The
+ * String is composed of the characters currently in this StringBuilder. Note
+ * that the result is a copy, and that future modifications to this buffer
+ * do not affect the String.
+ *
+ * @return the characters in this StringBuilder
+ */
+ public String toString()
+ {
+ return new String(this);
+ }
+
+ /**
+ * Predicate which determines if a substring of this matches another String
+ * starting at a specified offset for each String and continuing for a
+ * specified length. This is more efficient than creating a String to call
+ * indexOf on.
+ *
+ * @param toffset index to start comparison at for this String
+ * @param other non-null String to compare to region of this
+ * @return true if regions match, false otherwise
+ * @see #indexOf(String, int)
+ * @see #lastIndexOf(String, int)
+ * @see String#regionMatches(boolean, int, String, int, int)
+ */
+ private boolean regionMatches(int toffset, String other)
+ {
+ int len = other.count;
+ int index = other.offset;
+ while (--len >= 0)
+ if (value[toffset++] != other.value[index++])
+ return false;
+ return true;
+ }
+}