envoy/src/main/java/envoy/client/data/SettingsItem.java

package envoy.client.data;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Consumer;

import javax.swing.JComponent;

import envoy.client.ui.primary.PrimaryToggleSwitch;

/**
 * Encapsulates a persistent value that is directly or indirectly mutable by the
 * user.<br>
 * <br>
 * Project: <strong>envoy-clientChess</strong><br>
 * File: <strong>SettingsItem.java</strong><br>
 * Created: <strong>23.12.2019</strong><br>
 *
 * @param <T> the type of this {@link SettingsItem}'s value
 * @author Kai S. K. Engelbart
 * @since Envoy Client v0.3-alpha
 */
public class SettingsItem<T> implements Serializable {

	private T							value;
	private Class<? extends JComponent>	componentClass;
	private String						userFriendlyName, description;

	transient private Consumer<T> changeHandler;

	private static final Map<Class<?>, Class<? extends JComponent>> componentClasses = new HashMap<>();

	private static final long serialVersionUID = 0L;

	static {
		componentClasses.put(Boolean.class, PrimaryToggleSwitch.class);
	}

	/**
	 * Initializes a {@link SettingsItem}. The default value's class will be mapped
	 * to a {@link JComponent} that can be used to display this {@link SettingsItem}
	 * to the user.
	 *
	 * @param value            the default value
	 * @param userFriendlyName the user friendly name (short)
	 * @param description      the description (long)
	 * @since Envoy Client v0.3-alpha
	 */
	public SettingsItem(T value, String userFriendlyName, String description) {
		this(value, componentClasses.get(value.getClass()));
		this.userFriendlyName	= userFriendlyName;
		this.description		= description;
	}

	/**
	 * Initializes a {@link SettingsItem}. The default value's class will be mapped
	 * to a specific {@link JComponent}. The mapping can also be disables if this
	 * parameter is {@code null}. In that case a {@link NullPointerException} will
	 * be thrown if the method {@link SettingsItem#getComponent()} is called.
	 *
	 * @param value          the default value
	 * @param componentClass the class of the {@link JComponent} to represent this
	 *                       {@link SettingsItem} with
	 * @since Envoy Client v0.3-alpha
	 */
	public SettingsItem(T value, Class<? extends JComponent> componentClass) {
		this.value			= value;
		this.componentClass	= componentClass;
	}

	/**
	 * @return an instance of the {@link JComponent} that represents this
	 *         {@link SettingsItem}
	 * @throws ReflectiveOperationException if the component initialization failed
	 * @throws SecurityException            if the component initialization failed
	 * @since Envoy Client v0.3-alpha
	 */
	public JComponent getComponent() throws ReflectiveOperationException, SecurityException {
		if (componentClass == null) throw new NullPointerException("Component class is null");
		return componentClass.getConstructor(SettingsItem.class).newInstance(this);
	}

	/**
	 * @return the value
	 * @since Envoy Client v0.3-alpha
	 */
	public T get() { return value; }

	/**
	 * Changes the value of this {@link SettingsItem}. If a {@code ChangeHandler} if
	 * defined, it will be invoked with this value.
	 *
	 * @param value the value to set
	 * @since Envoy Client v0.3-alpha
	 */
	public void set(T value) {
		if (changeHandler != null && value != this.value) changeHandler.accept(value);
		this.value = value;
	}

	/**
	 * @return the componentClass
	 * @since Envoy Client v0.3-alpha
	 */
	public Class<? extends JComponent> getComponentClass() { return componentClass; }

	/**
	 * @param componentClass the componentClass to set
	 * @since Envoy Client v0.3-alpha
	 */
	public void setComponentClass(Class<? extends JComponent> componentClass) { this.componentClass = componentClass; }

	/**
	 * @return the userFriendlyName
	 * @since Envoy Client v0.3-alpha
	 */
	public String getUserFriendlyName() { return userFriendlyName; }

	/**
	 * @param userFriendlyName the userFriendlyName to set
	 * @since Envoy Client v0.3-alpha
	 */
	public void setUserFriendlyName(String userFriendlyName) { this.userFriendlyName = userFriendlyName; }

	/**
	 * @return the description
	 * @since Envoy Client v0.3-alpha
	 */
	public String getDescription() { return description; }

	/**
	 * @param description the description to set
	 * @since Envoy Client v0.3-alpha
	 */
	public void setDescription(String description) { this.description = description; }

	/**
	 * Sets a {@code ChangeHandler} for this {@link SettingsItem}. It will be
	 * invoked with the current value once during the registration and every time
	 * when the value changes.
	 *
	 * @param changeHandler the changeHandler to set
	 * @since Envoy Client v0.3-alpha
	 */
	public void setChangeHandler(Consumer<T> changeHandler) {
		this.changeHandler = changeHandler;
		changeHandler.accept(value);
	}
}