/*
 * Copyright 2015 Martijn van der Woud - The Crimson Cricket Internet Services
 *
 *    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.crimsoncricket.ddd.domain.model;


import javax.persistence.MappedSuperclass;
import java.io.Serializable;
import java.util.Objects;

@MappedSuperclass
public abstract class Id implements Serializable {

    // No-arg constructor to keep Hibernate happy
    protected Id(){}

    protected Id(String id) {
        this.id = id;
    }

    private String id;

    public String id(){return this.id;}

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Id)) return false;
        Id id1 = (Id) o;
        return Objects.equals(id(), id1.id());
    }

    @Override
    public int hashCode() {
        return Objects.hash(id());
    }
}

/*
 * Copyright 2015 Martijn van der Woud - The Crimson Cricket Internet Services
 *
 *    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.crimsoncricket.ddd.domain.model;


import javax.persistence.MappedSuperclass;
import java.io.Serializable;
import java.util.Objects;

import static com.crimsoncricket.asserts.Assert.assertArgumentNotNull;
import static com.crimsoncricket.asserts.Assert.assertStringArgumentNotEmpty;

@MappedSuperclass
public abstract class Id implements Serializable {

    // No-arg constructor to keep Hibernate happy
    protected Id(){}

    protected Id(String id) {
        assertArgumentNotNull(id, "id may not be null");
        assertStringArgumentNotEmpty(id, "id may not be empty");
        this.id = id;
    }

    private String id;

    public String id(){return this.id;}

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Id)) return false;
        Id id1 = (Id) o;
        return Objects.equals(id(), id1.id());
    }

    @Override
    public int hashCode() {
        return Objects.hash(id());
    }
}

Add validations for Id values