1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package java.lang; 19 20 21 /** 22 * This interface represents an ordered set of characters and defines the 23 * methods to probe them. 24 */ 25 public interface CharSequence { 26 27 /** 28 * Returns the number of characters in this sequence. 29 * 30 * @return the number of characters. 31 */ length()32 public int length(); 33 34 /** 35 * Returns the character at {@code index}. 36 * @throws IndexOutOfBoundsException if {@code index < 0} or {@code index >= length()}. 37 */ charAt(int index)38 public char charAt(int index); 39 40 /** 41 * Returns a {@code CharSequence} from the {@code start} index (inclusive) 42 * to the {@code end} index (exclusive) of this sequence. 43 * 44 * @param start 45 * the start offset of the sub-sequence. It is inclusive, that 46 * is, the index of the first character that is included in the 47 * sub-sequence. 48 * @param end 49 * the end offset of the sub-sequence. It is exclusive, that is, 50 * the index of the first character after those that are included 51 * in the sub-sequence 52 * @return the requested sub-sequence. 53 * @throws IndexOutOfBoundsException 54 * if {@code start < 0}, {@code end < 0}, {@code start > end}, 55 * or if {@code start} or {@code end} are greater than the 56 * length of this sequence. 57 */ subSequence(int start, int end)58 public CharSequence subSequence(int start, int end); 59 60 /** 61 * Returns a string with the same characters in the same order as in this 62 * sequence. 63 * 64 * @return a string based on this sequence. 65 */ toString()66 public String toString(); 67 } 68