fe/src/main/java/org/apache/doris/common/Id.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
//
//   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.apache.doris.common;

import java.util.ArrayList;

/**
 * Integer ids that cannot accidentally be compared with ints.
 */
public class Id<IdType extends Id<IdType>> {
    static private int INVALID_ID = -1;
    protected final int id;

    public Id() {
        this.id = INVALID_ID;
    }

    public Id(int id) {
        this.id = id;
    }

    public boolean isValid() {
        return id != INVALID_ID;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }

        // only ids of the same subclass are comparable
        if (obj.getClass() != this.getClass()) {
            return false;
        }
        return ((Id) obj).id == id;
    }

    @Override
    public int hashCode() {
        return Integer.valueOf(id).hashCode();
    }

    public int asInt() {
        return id;
    }

    public ArrayList<IdType> asList() {
        ArrayList<IdType> list = new ArrayList<IdType>();
        list.add((IdType) this);
        return list;
    }

    public String toString() {
        return Integer.toString(id);
    }
}