AggregateMember.java

package de.japrost.jabudget.domain.account;

/**
 * A member of an aggregate. Has a key as unique identifier.
 */
public abstract class AggregateMember {

    /** Separator between parts of a key */
    public static final String KEY_SEPARATOR = ":";

    /**
     * Get the key of the {@link AggregateMember}.
     *
     * @return the key, composed with the KEY_SEPARATOR.
     */
    public abstract String key();

    /**
     * {@inheritDoc} <br>
     * <strong>This implementation</strong> uses the {@link AggregateMember#key()}.
     */
    @Override
    public int hashCode() {
        return key().hashCode();
    }

    /**
     * {@inheritDoc} <br>
     * <strong>This implementation</strong> uses the {@link AggregateMember#key()}.
     */
    @Override
    public boolean equals(final Object obj) {
        if (this == obj) {
            return true;
        }
        if (!(obj instanceof AggregateMember)) {
            return false;
        }
        final AggregateMember other = (AggregateMember) obj;
        if (key().equals(other.key())) {
            return true;
        }
        return false;
    }

}