spring复习：（26）BeanMetadataAttribute和BeanMetadataAttributeAccessor

public class BeanMetadataAttribute implements BeanMetadataElement {

	private final String name;

	@Nullable
	private final Object value;

	@Nullable
	private Object source;


	/**
	 * Create a new AttributeValue instance.
	 * @param name the name of the attribute (never {@code null})
	 * @param value the value of the attribute (possibly before type conversion)
	 */
	public BeanMetadataAttribute(String name, @Nullable Object value) {
		Assert.notNull(name, "Name must not be null");
		this.name = name;
		this.value = value;
	}


	/**
	 * Return the name of the attribute.
	 */
	public String getName() {
		return this.name;
	}

	/**
	 * Return the value of the attribute.
	 */
	@Nullable
	public Object getValue() {
		return this.value;
	}

	/**
	 * Set the configuration source {@code Object} for this metadata element.
	 * 
The exact type of the object will depend on the configuration mechanism used.
	 */
	public void setSource(@Nullable Object source) {
		this.source = source;
	}

	@Override
	@Nullable
	public Object getSource() {
		return this.source;
	}


	@Override
	public boolean equals(@Nullable Object other) {
		if (this == other) {
			return true;
		}
		if (!(other instanceof BeanMetadataAttribute)) {
			return false;
		}
		BeanMetadataAttribute otherMa = (BeanMetadataAttribute) other;
		return (this.name.equals(otherMa.name) &&
				ObjectUtils.nullSafeEquals(this.value, otherMa.value) &&
				ObjectUtils.nullSafeEquals(this.source, otherMa.source));
	}

	@Override
	public int hashCode() {
		return this.name.hashCode() * 29 + ObjectUtils.nullSafeHashCode(this.value);
	}

	@Override
	public String toString() {
		return "metadata attribute '" + this.name + "'";
	}

}

主要提供了name , value, source三个属性。

public class BeanMetadataAttributeAccessor extends AttributeAccessorSupport implements BeanMetadataElement {

	@Nullable
	private Object source;


	/**
	 * Set the configuration source {@code Object} for this metadata element.
	 * 
The exact type of the object will depend on the configuration mechanism used.
	 */
	public void setSource(@Nullable Object source) {
		this.source = source;
	}

	@Override
	@Nullable
	public Object getSource() {
		return this.source;
	}


	/**
	 * Add the given BeanMetadataAttribute to this accessor's set of attributes.
	 * @param attribute the BeanMetadataAttribute object to register
	 */
	public void addMetadataAttribute(BeanMetadataAttribute attribute) {
		super.setAttribute(attribute.getName(), attribute);
	}

	/**
	 * Look up the given BeanMetadataAttribute in this accessor's set of attributes.
	 * @param name the name of the attribute
	 * @return the corresponding BeanMetadataAttribute object,
	 * or {@code null} if no such attribute defined
	 */
	@Nullable
	public BeanMetadataAttribute getMetadataAttribute(String name) {
		return (BeanMetadataAttribute) super.getAttribute(name);
	}

	@Override
	public void setAttribute(String name, @Nullable Object value) {
		super.setAttribute(name, new BeanMetadataAttribute(name, value));
	}

	@Override
	@Nullable
	public Object getAttribute(String name) {
		BeanMetadataAttribute attribute = (BeanMetadataAttribute) super.getAttribute(name);
		return (attribute != null ? attribute.getValue() : null);
	}

	@Override
	@Nullable
	public Object removeAttribute(String name) {
		BeanMetadataAttribute attribute = (BeanMetadataAttribute) super.removeAttribute(name);
		return (attribute != null ? attribute.getValue() : null);
	}

}

主要通过继承的AttributeAccessorSupport里的map来保存和读取BeanMetadataAttibute数据。