IntList.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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
 *
 *   https://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.apache.bcel.verifier.statics;

import java.util.HashSet;
import java.util.Set;

/**
 * A small utility class representing a set of basic int values.
 */
public class IntList {

    /** The ints are stored as Integer objects in a hash set so that {@link #contains(int)} is O(1), not a linear scan. */
    private final Set<Integer> set;

    /** This constructor creates an empty list. */
    IntList() {
        set = new HashSet<>();
    }

    /** Adds an element to the list. */
    void add(final int i) {
        set.add(Integer.valueOf(i));
    }

    /** Tests if the specified int is already in the list. */
    boolean contains(final int i) {
        return set.contains(Integer.valueOf(i));
    }
}