1 /* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.dx.rop.cst; 18 19 /** 20 * Interface for constant pools, which are, more or less, just lists of 21 * {@link Constant} objects. 22 */ 23 public interface ConstantPool { 24 /** 25 * Get the "size" of the constant pool. This corresponds to the 26 * class file field {@code constant_pool_count}, and is in fact 27 * always at least one more than the actual size of the constant pool, 28 * as element {@code 0} is always invalid. 29 * 30 * @return {@code >= 1;} the size 31 */ 32 public int size(); 33 34 /** 35 * Get the {@code n}th entry in the constant pool, which must 36 * be valid. 37 * 38 * @param n {@code n >= 0, n < size();} the constant pool index 39 * @return {@code non-null;} the corresponding entry 40 * @throws IllegalArgumentException thrown if {@code n} is 41 * in-range but invalid 42 */ 43 public Constant get(int n); 44 45 /** 46 * Get the {@code n}th entry in the constant pool, which must 47 * be valid unless {@code n == 0}, in which case {@code null} 48 * is returned. 49 * 50 * @param n {@code n >= 0, n < size();} the constant pool index 51 * @return {@code null-ok;} the corresponding entry, if {@code n != 0} 52 * @throws IllegalArgumentException thrown if {@code n} is 53 * in-range and non-zero but invalid 54 */ 55 public Constant get0Ok(int n); 56 57 /** 58 * Get the {@code n}th entry in the constant pool, or 59 * {@code null} if the index is in-range but invalid. In 60 * particular, {@code null} is returned for index {@code 0} 61 * as well as the index after any entry which is defined to take up 62 * two slots (that is, {@code Long} and {@code Double} 63 * entries). 64 * 65 * @param n {@code n >= 0, n < size();} the constant pool index 66 * @return {@code null-ok;} the corresponding entry, or {@code null} if 67 * the index is in-range but invalid 68 */ 69 public Constant getOrNull(int n); 70 71 /** 72 * Get all entries in this constant pool. 73 * 74 * @return the returned array may contain null entries. 75 */ 76 public Constant[] getEntries(); 77 } 78
