content: /*
   * Copyright (C) 2007 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.taobao.android.dx.rop.cst;
  
  /**
   * Interface for constant pools, which are, more or less, just lists of
   * {@link Constant} objects.
   */
  public interface ConstantPool {
      /**
       * Get the "size" of the constant pool. This corresponds to the
       * class file field {@code constant_pool_count}, and is in fact
       * always at least one more than the actual size of the constant pool,
       * as element {@code 0} is always invalid.
       *
       * @return {@code >= 1;} the size
       */
      public int size();
  
      /**
       * Get the {@code n}th entry in the constant pool, which must
       * be valid.
       *
       * @param n {@code n >= 0, n < size();} the constant pool index
       * @return {@code non-null;} the corresponding entry
       * @throws IllegalArgumentException thrown if {@code n} is
       * in-range but invalid
       */
      public Constant get(int n);
  
      /**
       * Get the {@code n}th entry in the constant pool, which must
       * be valid unless {@code n == 0}, in which case {@code null}
       * is returned.
       *
       * @param n {@code n >= 0, n < size();} the constant pool index
       * @return {@code null-ok;} the corresponding entry, if {@code n != 0}
       * @throws IllegalArgumentException thrown if {@code n} is
       * in-range and non-zero but invalid
       */
      public Constant get0Ok(int n);
  
      /**
       * Get the {@code n}th entry in the constant pool, or
       * {@code null} if the index is in-range but invalid. In
       * particular, {@code null} is returned for index {@code 0}
       * as well as the index after any entry which is defined to take up
       * two slots (that is, {@code Long} and {@code Double}
       * entries).
       *
       * @param n {@code n >= 0, n < size();} the constant pool index
       * @return {@code null-ok;} the corresponding entry, or {@code null} if
       * the index is in-range but invalid
       */
      public Constant getOrNull(int n);
  
      /**
       * Get all entries in this constant pool.
       *
       * @return the returned array may contain null entries.
       */
      public Constant[] getEntries();
  }
  