envoy/src/main/java/envoy/data/MessageBuilder.java

package envoy.data;

import java.util.Date;

import envoy.data.Message.MessageStatus;

/**
 * Provides a method of constructing the {@link Message} class.<br>
 * <br>
 * Project: <strong>envoy-common</strong><br>
 * File: <strong>MessageBuilder.java</strong><br>
 * Created: <strong>31.12.2019</strong><br>
 *
 * @author Kai S. K. Engelbart
 * @since Envoy Common v0.2-alpha
 */
public class MessageBuilder {

	// Mandatory properties without default values
	private final long senderId, recipientId;

	// Properties with default values
	private long					id;
	private Date					creationDate;
	private String					text;
	private MessageAttachment<?>	attachment;
	private Message.MessageStatus	status;

	/**
	 * Creates an instance of {@link MessageBuilder} with all mandatory values
	 * without defaults for the {@link Message} class.
	 *
	 * @param senderId    the ID of the user who sends the {@link Message}
	 * @param recipientId the ID of the user who received the {@link Message}
	 * @param idGenerator the ID generator used to generate a unique {@link Message}
	 *                    id
	 * @since Envoy Common v0.2-alpha
	 */
	public MessageBuilder(long senderId, long recipientId, IdGenerator idGenerator) {
		this(senderId, recipientId, idGenerator.next());
	}

	/**
	 * Creates an instance of {@link MessageBuilder} with all mandatory values
	 * without defaults for the {@link Message} class.
	 *
	 * @param senderId    the ID of the user who sends the {@link Message}
	 * @param recipientId the ID of the user who received the {@link Message}
	 * @param messageId   the ID of the {@link Message}
	 * @since Envoy Common v0.2-alpha
	 */
	public MessageBuilder(long senderId, long recipientId, long messageId) {
		this.senderId		= senderId;
		this.recipientId	= recipientId;
		id					= messageId;
	}

	/**
	 * Creates an instance of {@link Message} with the previously supplied values.
	 * If a mandatory value is not set, a default value will be used instead:<br>
	 * <br>
	 * <table border="1">
	 * <tr>
	 * <td>{@code date}</td>
	 * <td>{@code new Date()}</td>
	 * <tr>
	 * <tr>
	 * <td>{@code text}</td>
	 * <td>{@code ""}</td>
	 * <tr>
	 * <tr>
	 * <td>{@code status}</td>
	 * <td>{@code MessageStatus.WAITING}</td>
	 * <tr>
	 * </table>
	 *
	 * @return a new instance of {@link Message}
	 * @since Envoy Common v0.2-alpha
	 */
	public Message build() {
		// Supplement default values
		if (creationDate == null) creationDate = new Date();
		if (text == null) text = "";
		if (status == null) status = MessageStatus.WAITING;

		return new Message(id, senderId, recipientId, creationDate, text, attachment, status);
	}

	/**
	 * @param creationDate the creation date of the {@link Message} to create
	 * @return this {@link MessageBuilder}
	 * @since Envoy Common v0.2-alpha
	 */
	public MessageBuilder setDate(Date creationDate) {
		this.creationDate = creationDate;
		return this;
	}

	/**
	 * @param text the text of the {@link Message} to create
	 * @return this {@link MessageBuilder}
	 * @since Envoy Common v0.2-alpha
	 */
	public MessageBuilder setText(String text) {
		this.text = text;
		return this;
	}

	/**
	 * @param attachment the {@link MessageAttachment} of the {@link Message} to
	 *                   create
	 * @return this {@link MessageBuilder}
	 * @since Envoy Common v0.2-alpha
	 */
	public MessageBuilder setAttachment(MessageAttachment<?> attachment) {
		this.attachment = attachment;
		return this;
	}

	/**
	 * @param status the {@link MessageStatus} of the {@link Message} to create
	 * @return this {@link MessageBuilder}
	 * @since Envoy Common v0.2-alpha
	 */
	public MessageBuilder setStatus(Message.MessageStatus status) {
		this.status = status;
		return this;
	}
}