AttributeRemover.java

package fr.openwide.core.wicket.behavior;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.apache.wicket.Component;
import org.apache.wicket.behavior.Behavior;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.parser.XmlTag.TagType;
import org.apache.wicket.model.IModel;
import org.apache.wicket.util.lang.Args;
import org.apache.wicket.util.value.IValueMap;

public class AttributeRemover extends Behavior {
	private static final long serialVersionUID = -5358213150482831485L;

	public static final String VALUELESS_ATTRIBUTE = "VA";

	private static final String DEFAULT_ATTRIBUTE_SEPARATOR = " ";

	private final String attribute;

	private final IModel<?> removeModel;

	private final String separator;

	public AttributeRemover(final String attribute, final IModel<?> removeModel) {
		this(attribute, removeModel, DEFAULT_ATTRIBUTE_SEPARATOR);
	}

	public AttributeRemover(final String attribute, final IModel<?> removeModel, String separator) {
		super();
		
		Args.notNull(attribute, "attribute");
		
		this.attribute = attribute;
		this.removeModel = removeModel;
		this.separator = separator;
	}

	@Override
	public final void onComponentTag(Component component, ComponentTag tag) {
		if (tag.getType() != TagType.CLOSE) {
			replaceAttributeValue(tag);
		}
	}

	private void replaceAttributeValue(ComponentTag tag) {
		if (removeModel != null && removeModel.getObject() != VALUELESS_ATTRIBUTE) {
			final IValueMap tagAttributes = tag.getAttributes();
			Object attributeValue = tagAttributes.get(attribute);
			
			List<String> valuesToRemove = getClassesToRemove();
			
			if (attributeValue != null && !valuesToRemove.isEmpty()) {
				List<String> values = Arrays.asList(attributeValue.toString().split(separator));
				
				StringBuilder newAttributeValue = new StringBuilder();
				for (String value : values) {
					if (!valuesToRemove.contains(value)) {
						newAttributeValue.append(value).append(separator);
					}
				}
				
				tagAttributes.put(attribute, newAttributeValue);
			}
		}
	}

	private List<String> getClassesToRemove() {
		if (removeModel != null && removeModel.getObject() != null) {
			return Arrays.asList(removeModel.getObject().toString().split(separator));
		}
		return new ArrayList<String>();
	}

	@Override
	public String toString() {
		return "[AttributeRemover attribute=" + attribute + ", removeModel=" + removeModel + "]";
	}

	@Override
	public void detach(Component component) {
		super.detach(component);
		if (removeModel != null) {
			removeModel.detach();
		}
	}
}