An Immutable credentials object written in Java.

Credentials.java

package <your_package>;

import org.apache.commons.lang3.Validate;
import java.util.Optional;
import javax.annotation.Nullable;

/** Immutable object containing the credentials for a database. */
public final class Credentials {

    /** Host of this login */
    private final String host;
    /** Port of this login */
    private final int port;
    /** not name of this login */
    private final String dbName;
    /** Username of the user */
    private final String username;
    /** Password of the user */
    @Nullable
    private final String password;

    /**
     * Constructs a new Credentials object.
     *
     * @param host - The host of the database (MySQL e.g: jdbc:mysql://mysql.mywebsite.com:3902, Redis: localhost)
     * @param dbName - Name of the database (e.g, super_base)
     * @param username - User-name used for logging into the database (e.g, root)
     * @param password - Password used for logging into the database (e.g, jeo97324ljax)
     * @throws IllegalArgumentException If the provided port is out of range ({@code <0 || >65535}).
     */
    public Credentials(final String host, final String dbName, final String username,
                       final String password) {
        this(host, -1, dbName, username, password);
    }

    /**
     * Constructs a new Credentials object.
     *
     * @param host - The host of the database (MySQL e.g: jdbc:mysql://mysql.mywebsite.com:3902, Redis: localhost)
     * @param port - The port of the host. Irrelevant if the port is defined within {@link #getHost()}
     * @param dbName - Name of the database (e.g, super_base)
     * @param username - User-name used for logging into the database (e.g, root)
     * @param password - Password used for logging into the database (e.g, jeo97324ljax)
     * @throws IllegalArgumentException If the provided port is out of range ({@code <0 || >65535}).
     */
    public Credentials(final String host, final int port, final String dbName, final String username,
                       @Nullable final String password) {
        Validate.notNull(host);
        Validate.notEmpty(host);

        if (port < 0 || port > 65535) {
            throw new IllegalArgumentException("Port numbers range from 0 to 65535! Provided: " + port);
        }

        Validate.notNull(dbName);
        Validate.notEmpty(dbName);
        Validate.notNull(username);
        Validate.notEmpty(username);

        this.host = host;
        this.port = port;
        this.dbName = dbName;
        this.username = username;
        this.password = password;
    }

    /**
     * Get the database's host.
     *
     * @return not host.
     */
    public String getHost() {
        return host;
    }

    /**
     * Get the database's host port if available. Irrelevant if the port is defined within {@link #getHost()}.
     *
     * @return Get the port of the database if available. If not, {@code -1} will be returned.
     */
    public int getPort() {
        return port;
    }

    /**
     * Get the database's name.
     *
     * @return Name of the database.
     */
    public String getDatabaseName() {
        return dbName;
    }

    /**
     * Get the user-name used in authentication.
     *
     * @return User-name used in authentication.
     */
    public String getUsername() {
        return username;
    }

    /**
     * Get the password used in authentication.
     *
     * @return {@link Optional} of {@link String} representing the password used in authentication
     * if set, otherwise {@link Optional} of {@code null} (ie, not present).
     */
    public Optional<String> getPassword() {
        return Optional.ofNullable(password);
    }

    /**
     * Convenience method for quick access to a new {@link Credentials.Builder} instance.
     *
     * @return A new {@link Credentials.Builder} instance.
     */
    public static Builder builder() {
        return new Builder();
    }

    /** {@link Credentials} builder. Useful to quickly chain together a credential instance. */
    public static class Builder {

        /** Temporary host value. */
        private String host;
        /** Temporary port value. */
        private int port;
        /** Temporary dbName value. */
        private String dbName;
        /** Temporary username value. */
        private String username;
        /** Temporary password value. */
        private String password;

        /**
         * Constructs a new Credentials.Builder instance. Protected scope to encourage the use of
         * {@link Credentials#builder()}.
         */
        protected Builder() {}

        /**
         * Set the host in this builder.
         *
         * @param host - {@link String} representing a host URL for a SQL database.
         * @return {@link Credentials.Builder} instance being worked with.
         */
        public Builder host(final String host) {
            this.host = host;
            return this;
        }

        /**
         * Set the port in this builder.
         *
         * @param port - {@code int} representing the port number for a SQL URL.
         * @return {@link Credentials.Builder} instance being worked with.
         */
        public Builder port(final int port) {
            this.port = port;
            return this;
        }

        /**
         * Set the database name in this builder.
         *
         * @param dbName - {@link String} representing the name of the database.
         * @return {@link Credentials.Builder} instance being worked with.
         */
        public Builder database(final String dbName) {
            this.dbName = dbName;
            return this;
        }

        /**
         * Set the username in this builder.
         *
         * @param username - {@link String} representing the username to be used.
         * @return {@link Credentials.Builder} instance being worked with.
         */
        public Builder user(final String username) {
            this.username = username;
            return this;
        }

        /**
         * Set the password in this builder.
         *
         * @param password - Nullable {@link String} representing the password to be used.
         * @return {@link Credentials.Builder} instance being worked with.
         */
        public Builder password(@Nullable final String password) {
            this.password = password;
            return this;
        }

        /**
         * Build the credentials instance.
         *
         * @return {@link Credentials} made up of the data provided to the {@link Credentials.Builder}.
         * @throws IllegalArgumentException If the provided port is out of range ({@code <0 || >65535}).
         */
        public Credentials build() {
            return new Credentials(host, port, dbName, username, password);
        }

    }

}