Java String 的 equals() 方法可能的优化

public final class String











　  implements java.io.Serializable, Comparable<String>, CharSequence











{











　  /** The value is used for character storage. */











　  PRivate final char value[];












 


 



 



  　/** The offset is the first index of the storage that is used. */











　  private final int offset;












 


 



 



　  /** The count is the number of characters in the String. */











　  private final int count;

　  /**











　　 * Initializes a newly created <code>String</code> object so that it











　　 * represents the same sequence of characters as the argument; in other











　　 * Words, the newly created string is a copy of the argument string. Unless











　　 * an eXPlicit copy of <code>original</code> is needed, use of this











　　 * constrUCtor is unnecessary since Strings are immutable.











　　 *











　　 * @param　 original　 a <code>String</code>.











　　 */











　  public String(String original) {











　　　　　  int size = original.count;











　　　　　  char[] originalValue = original.value;











　　　　　  char[] v;











  　　　　  if (originalValue.length > size) {











　　　　　  　  // The array representing the String is bigger than the new











　　　　　  　  // String itself.  Perhaps this constructor is being called











　　　　　  　  // in order to trim the baggage, so make a copy of the array.











　　　　　  　  v = new char[size];











　　　　　  　  System.arraycopy(originalValue, original.offset, v, 0, size);











　　　　　  } else {











　　　　　  　  // The array representing the String is the same











　　　　　  　  // size as the String, so no point in making a copy.











　　　　　  　  v = originalValue;











　　　　　  }











　　　　　  this.offset = 0;











　　　　　  this.count = size;











　　　　　  this.value = v;











　  }