[面试]StringBuilder StringBuffer源码粘贴(并非源码分析, 请绕道)
StringBuilder StringBuffer 源码
这里只是我个人笔记, 并没有在这篇文章里做任何技术分享, 请同学们绕道- -.如果需要我会后期补上的.....
本来是想分析源码来着, 但是发现这部分源码相对简单.....比较容易看懂...
最近看了StringBuilder StringBuffer的源码, 自己新建为了MyStringBuilder MyStringBuffer. 代码贴了出来, 留个记录, 当做笔记了.
(或者github:https://github.com/GoldArowana/my-concurrency/tree/master/src/main/java/com/king/learn/string)
AbstractStringBuilder
import java.lang.reflect.Method;
import java.util.Arrays;
/**
* 一个可变的字符串
*/
public abstract class MyAbstractStringBuilder implements Appendable, CharSequence {
/**
* 用于存储字符串
*/
char[] value;
/**
* 数组value中有多少是使用中的
*/
int count;
/**
* 根据传入的大小进行初始化数组.
*/
MyAbstractStringBuilder(int capacity) {
value = new char[capacity];
}
/**
* 数组value中有多少是使用中的
*/
@Override
public int length() {
return count;
}
/**
* 当前对象的数组开辟了的空间是多少.
*/
public int capacity() {
return value.length;
}
/**
* 确保当前的数组的空间最小是minimumCapacity.
* 如果不够就去扩容.
*/
public void ensureCapacity(int minimumCapacity) {
if (minimumCapacity > 0)
ensureCapacityInternal(minimumCapacity);
}
/**
* 确保当前的数组的空间最小是minimumCapacity.
* 如果不够就去扩容.
*/
private void ensureCapacityInternal(int minimumCapacity) {
// overflow-conscious code
if (minimumCapacity - value.length > 0) {
value = Arrays.copyOf(value,
newCapacity(minimumCapacity));
}
}
/**
* 可开辟的最大空间.(虚拟机限制)
*/
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
/**
* minCapacity合法时, 按(value.length << 1) + 2 扩展
* 非法时(小于0, 或者超大时), 进行特殊处理.
*/
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;
}
/**
* 去掉数组中多余的(未使用)的空间.
*/
public void trimToSize() {
if (count < value.length) {
value = Arrays.copyOf(value, count);
}
}
/**
* 重定义大小
*/
public void setLength(int newLength) {
// 小于0, 非法, 抛异常.
if (newLength < 0) throw new StringIndexOutOfBoundsException(newLength);
// 确保当前数组最小是newLength大小.
ensureCapacityInternal(newLength);
// 如果数组的使用部分的大小小于newLength, 那么用ascii 0 填充
if (count < newLength) {
Arrays.fill(value, count, newLength, '\0');
}
// 如果数组的使用部分大于newLength, 那么直接把这个大小赋值就好了
// (有点像把指针往回拉的这样一个动作)
count = newLength;
}
@Override
public char charAt(int index) {
// 检查越界
if ((index < 0) || (index >= count))
throw new StringIndexOutOfBoundsException(index);
// 返回数组中对应的位置数据.
return value[index];
}
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);
}
public void setCharAt(int index, char ch) {
if ((index < 0) || (index >= count))
throw new StringIndexOutOfBoundsException(index);
value[index] = ch;
}
public MyAbstractStringBuilder append(Object obj) {
return append(String.valueOf(obj));
}
public MyAbstractStringBuilder 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;
}
public MyAbstractStringBuilder append(MyStringBuffer 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
*/
MyAbstractStringBuilder append(MyAbstractStringBuilder asb) {
if (asb == null)
return appendNull();
int len = asb.length();
ensureCapacityInternal(count + len);
asb.getChars(0, len, value, count);
count += len;
return this;
}
@Override
public MyAbstractStringBuilder append(CharSequence s) {
if (s == null)
return appendNull();
if (s instanceof MyAbstractStringBuilder)
return this.append((MyAbstractStringBuilder) s);
return this.append(s, 0, s.length());
}
private MyAbstractStringBuilder 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;
}
@Override
public MyAbstractStringBuilder 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;
}
public MyAbstractStringBuilder append(char[] str) {
int len = str.length;
ensureCapacityInternal(count + len);
System.arraycopy(str, 0, value, count, len);
count += len;
return this;
}
public MyAbstractStringBuilder 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;
}
public MyAbstractStringBuilder 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;
}
@Override
public MyAbstractStringBuilder append(char c) {
ensureCapacityInternal(count + 1);
value[count++] = c;
return this;
}
public MyAbstractStringBuilder 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;
}
/**
* appendCodePoint(0x5b57); // 0x5b57是“字”的unicode编码
*/
public MyAbstractStringBuilder 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);
try {
Method m = Character.class.getDeclaredMethod("toSurrogates", int.class, char[].class, int.class);
m.setAccessible(true);
m.invoke(null, codePoint, value, count);
// Character.toSurrogates(codePoint, value, count);
} catch (Exception e) {
e.printStackTrace();
}
this.count = count + 2;
} else {
throw new IllegalArgumentException();
}
return this;
}
public MyAbstractStringBuilder 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}.
*/
public MyAbstractStringBuilder 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);
try {
Method m = str.getClass().getDeclaredMethod("getChars", char[].class, int.class);
m.setAccessible(true);
m.invoke(str, value, start);
// str.getChars(value, start);
} catch (Exception e) {
e.printStackTrace();
}
count = newCount;
return this;
}
public String substring(int start) {
return substring(start, count);
}
@Override
public CharSequence subSequence(int start, int end) {
return substring(start, 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);
}
public MyAbstractStringBuilder 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;
}
public MyAbstractStringBuilder insert(int offset, Object obj) {
return insert(offset, String.valueOf(obj));
}
public MyAbstractStringBuilder 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);
try {
Method m = str.getClass().getDeclaredMethod("getChars", char[].class, int.class);
m.setAccessible(true);
m.invoke(str, value, offset);
// str.getChars(value, offset);
} catch (Exception e) {
e.printStackTrace();
}
count += len;
return this;
}
public MyAbstractStringBuilder 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;
}
public MyAbstractStringBuilder 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());
}
public MyAbstractStringBuilder 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 < end; i++)
value[dstOffset++] = s.charAt(i);
count += len;
return this;
}
public MyAbstractStringBuilder insert(int offset, boolean b) {
return insert(offset, String.valueOf(b));
}
public MyAbstractStringBuilder insert(int offset, char c) {
ensureCapacityInternal(count + 1);
System.arraycopy(value, offset, value, offset + 1, count - offset);
value[offset] = c;
count += 1;
return this;
}
public MyAbstractStringBuilder insert(int offset, int i) {
return insert(offset, String.valueOf(i));
}
public MyAbstractStringBuilder insert(int offset, long l) {
return insert(offset, String.valueOf(l));
}
public MyAbstractStringBuilder insert(int offset, float f) {
return insert(offset, String.valueOf(f));
}
public MyAbstractStringBuilder insert(int offset, double d) {
return insert(offset, String.valueOf(d));
}
public int indexOf(String str) {
return indexOf(str, 0);
}
public int indexOf(String str, int fromIndex) {
try {
Method m = String.class.getDeclaredMethod("indexOf", char[].class, int.class, int.class, String.class, int.class);
m.setAccessible(true);
return (int) m.invoke(null, value, 0, count, str, fromIndex);
// return String.indexOf(value, 0, count, str, fromIndex);
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException("反射异常");
}
}
public int lastIndexOf(String str) {
return lastIndexOf(str, count);
}
public int lastIndexOf(String str, int fromIndex) {
try {
Method m = String.class.getDeclaredMethod("lastIndexOf", char[].class, int.class, int.class, String.class, int.class);
m.setAccessible(true);
return (int) m.invoke(null, value, 0, count, str, fromIndex);
// return String.lastIndexOf(value, 0, count, str, fromIndex);
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException("反射异常");
}
}
/**
* 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.
* <p>
* Let <i>n</i> 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 <i>k</i> in the new character sequence is
* equal to the character at index <i>n-k-1</i> in the old
* character sequence.
*
* <p>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.
*/
public MyAbstractStringBuilder 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;
}
}
}
}
@Override
public abstract String toString();
}
StringBuilder
public final class MyStringBuilder extends MyAbstractStringBuilder {
public MyStringBuilder() {
super(16);
}
public MyStringBuilder(int capacity) {
super(capacity);
}
public MyStringBuilder(String str) {
super(str.length() + 16);
append(str);
}
public MyStringBuilder(CharSequence seq) {
this(seq.length() + 16);
append(seq);
}
@Override
public MyStringBuilder append(String str) {
super.append(str);
return this;
}
public MyStringBuilder append(StringBuffer sb) {
super.append(sb);
return this;
}
@Override
public MyStringBuilder append(CharSequence s) {
super.append(s);
return this;
}
@Override
public MyStringBuilder append(CharSequence s, int start, int end) {
super.append(s, start, end);
return this;
}
@Override
public MyStringBuilder append(char[] str) {
super.append(str);
return this;
}
@Override
public MyStringBuilder append(char[] str, int offset, int len) {
super.append(str, offset, len);
return this;
}
@Override
public MyStringBuilder append(boolean b) {
super.append(b);
return this;
}
@Override
public MyStringBuilder append(char c) {
super.append(c);
return this;
}
@Override
public MyStringBuilder appendCodePoint(int codePoint) {
super.appendCodePoint(codePoint);
return this;
}
@Override
public MyStringBuilder delete(int start, int end) {
super.delete(start, end);
return this;
}
@Override
public MyStringBuilder deleteCharAt(int index) {
super.deleteCharAt(index);
return this;
}
@Override
public MyStringBuilder replace(int start, int end, String str) {
super.replace(start, end, str);
return this;
}
@Override
public MyStringBuilder insert(int index, char[] str, int offset, int len) {
super.insert(index, str, offset, len);
return this;
}
@Override
public MyStringBuilder insert(int offset, Object obj) {
super.insert(offset, obj);
return this;
}
@Override
public MyStringBuilder insert(int offset, String str) {
super.insert(offset, str);
return this;
}
@Override
public MyStringBuilder insert(int offset, char[] str) {
super.insert(offset, str);
return this;
}
@Override
public MyStringBuilder insert(int dstOffset, CharSequence s) {
super.insert(dstOffset, s);
return this;
}
@Override
public MyStringBuilder insert(int dstOffset, CharSequence s, int start, int end) {
super.insert(dstOffset, s, start, end);
return this;
}
@Override
public MyStringBuilder insert(int offset, boolean b) {
super.insert(offset, b);
return this;
}
@Override
public MyStringBuilder insert(int offset, char c) {
super.insert(offset, c);
return this;
}
@Override
public MyStringBuilder insert(int offset, int i) {
super.insert(offset, i);
return this;
}
@Override
public MyStringBuilder insert(int offset, long l) {
super.insert(offset, l);
return this;
}
@Override
public MyStringBuilder insert(int offset, float f) {
super.insert(offset, f);
return this;
}
@Override
public MyStringBuilder insert(int offset, double d) {
super.insert(offset, d);
return this;
}
@Override
public int indexOf(String str) {
return super.indexOf(str);
}
@Override
public int indexOf(String str, int fromIndex) {
return super.indexOf(str, fromIndex);
}
@Override
public int lastIndexOf(String str) {
return super.lastIndexOf(str);
}
@Override
public int lastIndexOf(String str, int fromIndex) {
return super.lastIndexOf(str, fromIndex);
}
@Override
public MyStringBuilder reverse() {
super.reverse();
return this;
}
@Override
public String toString() {
// Create a copy, don't share the array
return new String(value, 0, count);
}
}
StringBuffer
看了源码, 发现, 就是方法上多了synchronized
import java.util.Arrays;
public final class MyStringBuffer extends MyAbstractStringBuilder {
/**
* A cache of the last value returned by toString. Cleared
* whenever the StringBuffer is modified.
*/
private transient char[] toStringCache;
public MyStringBuffer() {
super(16);
}
public MyStringBuffer(int capacity) {
super(capacity);
}
public MyStringBuffer(String str) {
super(str.length() + 16);
append(str);
}
public MyStringBuffer(CharSequence seq) {
this(seq.length() + 16);
append(seq);
}
@Override
public synchronized int length() {
return count;
}
@Override
public synchronized int capacity() {
return value.length;
}
@Override
public synchronized void ensureCapacity(int minimumCapacity) {
super.ensureCapacity(minimumCapacity);
}
@Override
public synchronized void trimToSize() {
super.trimToSize();
}
@Override
public synchronized void setLength(int newLength) {
toStringCache = null;
super.setLength(newLength);
}
@Override
public synchronized char charAt(int index) {
if ((index < 0) || (index >= count))
throw new StringIndexOutOfBoundsException(index);
return value[index];
}
@Override
public synchronized void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin) {
super.getChars(srcBegin, srcEnd, dst, dstBegin);
}
@Override
public synchronized void setCharAt(int index, char ch) {
if ((index < 0) || (index >= count)) throw new StringIndexOutOfBoundsException(index);
toStringCache = null;
value[index] = ch;
}
@Override
public synchronized MyStringBuffer append(Object obj) {
toStringCache = null;
super.append(String.valueOf(obj));
return this;
}
@Override
public synchronized MyStringBuffer append(String str) {
toStringCache = null;
super.append(str);
return this;
}
public synchronized MyStringBuffer append(MyStringBuffer sb) {
toStringCache = null;
super.append(sb);
return this;
}
@Override
synchronized MyStringBuffer append(MyAbstractStringBuilder asb) {
toStringCache = null;
super.append(asb);
return this;
}
@Override
public synchronized MyStringBuffer append(CharSequence s) {
toStringCache = null;
super.append(s);
return this;
}
@Override
public synchronized MyStringBuffer append(CharSequence s, int start, int end)
{
toStringCache = null;
super.append(s, start, end);
return this;
}
@Override
public synchronized MyStringBuffer append(char[] str) {
toStringCache = null;
super.append(str);
return this;
}
@Override
public synchronized MyStringBuffer append(char[] str, int offset, int len) {
toStringCache = null;
super.append(str, offset, len);
return this;
}
@Override
public synchronized MyStringBuffer append(boolean b) {
toStringCache = null;
super.append(b);
return this;
}
@Override
public synchronized MyStringBuffer append(char c) {
toStringCache = null;
super.append(c);
return this;
}
@Override
public synchronized MyStringBuffer appendCodePoint(int codePoint) {
toStringCache = null;
super.appendCodePoint(codePoint);
return this;
}
@Override
public synchronized MyStringBuffer delete(int start, int end) {
toStringCache = null;
super.delete(start, end);
return this;
}
@Override
public synchronized MyStringBuffer deleteCharAt(int index) {
toStringCache = null;
super.deleteCharAt(index);
return this;
}
@Override
public synchronized MyStringBuffer replace(int start, int end, String str) {
toStringCache = null;
super.replace(start, end, str);
return this;
}
@Override
public synchronized String substring(int start) {
return substring(start, count);
}
@Override
public synchronized CharSequence subSequence(int start, int end) {
return super.substring(start, end);
}
@Override
public synchronized String substring(int start, int end) {
return super.substring(start, end);
}
@Override
public synchronized MyStringBuffer insert(int index, char[] str, int offset, int len) {
toStringCache = null;
super.insert(index, str, offset, len);
return this;
}
@Override
public synchronized MyStringBuffer insert(int offset, Object obj) {
toStringCache = null;
super.insert(offset, String.valueOf(obj));
return this;
}
@Override
public synchronized MyStringBuffer insert(int offset, String str) {
toStringCache = null;
super.insert(offset, str);
return this;
}
@Override
public synchronized MyStringBuffer insert(int offset, char[] str) {
toStringCache = null;
super.insert(offset, str);
return this;
}
@Override
public MyStringBuffer insert(int dstOffset, CharSequence s) {
// Note, synchronization achieved via invocations of other StringBuffer methods
// after narrowing of s to specific type
// Ditto for toStringCache clearing
super.insert(dstOffset, s);
return this;
}
@Override
public synchronized MyStringBuffer insert(int dstOffset, CharSequence s, int start, int end) {
toStringCache = null;
super.insert(dstOffset, s, start, end);
return this;
}
@Override
public MyStringBuffer insert(int offset, boolean b) {
// Note, synchronization achieved via invocation of StringBuffer insert(int, String)
// after conversion of b to String by super class method
// Ditto for toStringCache clearing
super.insert(offset, b);
return this;
}
@Override
public synchronized MyStringBuffer insert(int offset, char c) {
toStringCache = null;
super.insert(offset, c);
return this;
}
@Override
public MyStringBuffer insert(int offset, int i) {
// Note, synchronization achieved via invocation of StringBuffer insert(int, String)
// after conversion of i to String by super class method
// Ditto for toStringCache clearing
super.insert(offset, i);
return this;
}
@Override
public MyStringBuffer insert(int offset, long l) {
// Note, synchronization achieved via invocation of StringBuffer insert(int, String)
// after conversion of l to String by super class method
// Ditto for toStringCache clearing
super.insert(offset, l);
return this;
}
@Override
public MyStringBuffer insert(int offset, float f) {
// Note, synchronization achieved via invocation of StringBuffer insert(int, String)
// after conversion of f to String by super class method
// Ditto for toStringCache clearing
super.insert(offset, f);
return this;
}
@Override
public MyStringBuffer insert(int offset, double d) {
// Note, synchronization achieved via invocation of StringBuffer insert(int, String)
// after conversion of d to String by super class method
// Ditto for toStringCache clearing
super.insert(offset, d);
return this;
}
@Override
public int indexOf(String str) {
// Note, synchronization achieved via invocations of other StringBuffer methods
return super.indexOf(str);
}
@Override
public synchronized int indexOf(String str, int fromIndex) {
return super.indexOf(str, fromIndex);
}
@Override
public int lastIndexOf(String str) {
// Note, synchronization achieved via invocations of other StringBuffer methods
return lastIndexOf(str, count);
}
@Override
public synchronized int lastIndexOf(String str, int fromIndex) {
return super.lastIndexOf(str, fromIndex);
}
@Override
public synchronized MyStringBuffer reverse() {
toStringCache = null;
super.reverse();
return this;
}
@Override
public synchronized String toString() {
if (toStringCache == null) {
toStringCache = Arrays.copyOfRange(value, 0, count);
}
return new String(toStringCache);
}
}
---------------------------------------------------------
学如不及，犹恐失之
学如不及，犹恐失之
