org.snapscript.dx.rop.cst.ConstantPool Maven / Gradle / Ivy
/*
* 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 org.snapscript.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);
}