org.ioc.commons.ui.impl.HasValueAdapter Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of ioc-commons-ext Show documentation

Library which contains some extension classes for the library IOC-Commons. It provides some interface definitions and some tool classes which are non-dependent from the used technology; i.e. the classes and interfaces from this library do not depend on the choosen ioc-commons-implementation library.

There is a newer version: 1.2.1

Show newest version

package org.ioc.commons.ui.impl;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.ioc.commons.ui.HasValue;
import org.ioc.commons.ui.IsWidget;

public class HasValueAdapter implements HasValue {

	protected D value;
	private OnChangeCommand onChangeCommand;

	public HasValueAdapter() {
		// Nothing
	}

	public HasValueAdapter(D initialValue) {
		this.value = initialValue;
	}

	@Override
	public void setValue(D value) {
		// Override me
		boolean changed = (value == null ? this.value != null : !value.equals(this.value));
		this.value = value;
		if (this.onChangeCommand != null && changed) {
			this.onChangeCommand.execute(value);
		}
	}

	@Override
	public D getValue() {
		return this.value;
	}

	private static final Map> globalFields = new HashMap>();

	/**
	 * It creates a new adapter instance for a field owned by a widget and keep
	 * it in memory for reusing in the next calls. The widget will be
	 * responsible for cleaning them from memory when it is not going to use
	 * them anymore by calling {@link #cleanAdapters(IsWidget)} method. 

	 * 

	 * Usage:	{@literal @}Override
	public HasValue<Short> divider() {
		return HasValueAdapter.<Short> forField("divider", this).onChange(new OnChangeCommand<Short>() {

			{@literal @}Override
			public void execute(Short value) {
				lblDivider.setText(value != null ? value.toString() : "--");
			}
		});
	}
	
	...
	
	{@literal @}Override
	protected void onUnload() {
		super.onUnload();
		HasValueAdapter.cleanAdapters(this);
	}

	 * 
	 * 
	 * @param fieldName
	 *            Unique name of the field on the owner
	 * @param fieldOwner
	 *            The owner of the field
	 * @return An unique instance for this field in this field owner.
	 */
	public static  HasValueAdapter forField(String fieldName, IsWidget fieldOwner) {
		HasValueAdapter adapter = forField(fieldName, fieldOwner, null);
		return adapter;
	}

	/**
	 * 
	 * @param fieldName
	 *            Unique name of the field on the owner
	 * @param fieldOwner
	 *            The owner of the field
	 * @param initialValue
	 *            Initial value
	 * @see #forField(String, IsWidget)
	 * @return An unique instance for this field in this field owner.
	 */
	@SuppressWarnings("unchecked")
	public static  HasValueAdapter forField(String fieldName, IsWidget fieldOwner, D initialValue) {
		Field field = new Field(fieldName, fieldOwner);
		HasValueAdapter adapter = globalFields.get(field);
		if (adapter == null) {
			adapter = new HasValueAdapter(initialValue);
			globalFields.put(field, adapter);
		}
		return (HasValueAdapter) adapter;
	}

	/**
	 * Clean all the instantiated adapters for this owner using
	 * {@link HasValueAdapter#forField(String, IsWidget)} method.
	 * 
	 * @param fromOwner
	 *            Owner of the fields
	 */
	public static void cleanAdapters(IsWidget fromOwner) {
		cleanAdapters((Object) fromOwner);
	}

	public static void cleanAdapters(Object fromField) {
		for (Iterator it = globalFields.keySet().iterator(); it.hasNext();) {
			Field field = it.next();
			if (fromField.equals(field.getFieldOwner())) {
				it.remove();
			}
		}
	}

	/**
	 * Set a command to be executed when a change is produced.
	 * 
	 * @param onChangeCommand
	 *            Command to be executed.
	 * @return This adapter
	 */
	final public HasValueAdapter onChange(OnChangeCommand onChangeCommand) {
		this.onChangeCommand = onChangeCommand;
		return this;
	}

}