modules/sql-engine/src/main/java/org/apache/ignite/internal/sql/engine/property/Property.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.ignite.internal.sql.engine.property;

import java.util.Objects;
import org.apache.ignite.internal.tostring.IgniteToStringInclude;
import org.apache.ignite.internal.tostring.S;

/**
 * Describes an arbitrary property.
 *
 * <p>The properties is designed to be used in the following way:
 * <pre>
 *     class MyProperties {
 *         public static final Property&lt;String&gt; STRING_PROPERTY = new Property<>("string_prop_name", String.class);
 *         public static final Property&lt;Long&gt; LONG_PROPERTY = new Property<>("long_prop_name", Long.class);
 *     }
 *
 *     var holder = PropertiesHolder.holderFor(
 *             Map.of(
 *                     MyProperties.STRING_PROPERTY, "the value of a string prop",
 *                     MyProperties.LONG_PROPERTY, 42L
 *             )
 *     );
 *
 *     String stringVal = holder.get(MyProperties.STRING_PROPERTY);
 *     long longVal = holder.getOrDefault(MyProperties.LONG_PROPERTY, 10L);
 * </pre>
 *
 * @param <T> Expected value type with which the property is associated.
 */
public class Property<T> {
    /** Name of the property. */
    @IgniteToStringInclude
    public final String name;

    /** Expected value class with which the property is associated. */
    @IgniteToStringInclude
    public final Class<?> cls;

    /**
     * Constructor.
     *
     * @param name Name of the property.
     * @param cls Value class.
     */
    public Property(String name, Class<T> cls) {
        this.name = Objects.requireNonNull(name, "name");
        this.cls = Objects.requireNonNull(cls, "cls");
    }

    /** {@inheritDoc} */
    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }

        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        Property<?> property = (Property<?>) o;

        return name.equals(property.name);
    }

    /** {@inheritDoc} */
    @Override
    public int hashCode() {
        return name.hashCode();
    }

    /** {@inheritDoc} */
    @Override
    public String toString() {
        return S.toString(Property.class, this);
    }
}