package com.ctc.wstx.api;

import java.util.Set;
import java.util.TreeSet;

Optional handler used to determine if a specific empty element (by name) should
be allowed to use the self-closing syntax instead of having a separate end tag.
Since:
4.1/**
 * Optional handler used to determine if a specific empty element (by name) should
 * be allowed to use the self-closing syntax instead of having a separate end tag.
 * 
 * @since 4.1
 */
public interface EmptyElementHandler
{
    
Params:
prefix – The element's namespace prefix, null if not set
localName – The element's local name
nsURI – The elements's namespace URI, null if not set
allowEmpty – The allow empty setting specified by the caller.
Returns:
True if the empty element can be self-closing. False if a separate end tag should be written./**
     * @param prefix The element's namespace prefix, null if not set
     * @param localName The element's local name
     * @param nsURI The elements's namespace URI, null if not set
     * @param allowEmpty The allow empty setting specified by the caller.
     * @return True if the empty element can be self-closing. False if a separate end tag should be written.
     */
    public boolean allowEmptyElement(String prefix, String localName, String nsURI, boolean allowEmpty);
    
    
Handler that uses a Set of Strings. If the local part of the element's QName is contained
in the Set the element is allowed to be empty.
 Users of this class are encouraged to use a TreeSet with the String.CASE_INSENSITIVE_ORDER comparator if case-insensitive comparison is needed (like when dealing with HTML tags). /**
     * Handler that uses a Set of Strings. If the local part of the element's QName is contained
     * in the Set the element is allowed to be empty.
     *<p>
     * Users of this class are encouraged to use a {@link TreeSet} with the {@link String#CASE_INSENSITIVE_ORDER}
     * comparator if case-insensitive comparison is needed (like when dealing with HTML tags).
     */
    public static class SetEmptyElementHandler
        implements EmptyElementHandler
    {
        final protected Set<String> mEmptyElements;

        public SetEmptyElementHandler(Set<String> emptyElements)
        {
            mEmptyElements = emptyElements;
        }

        @Override
        public boolean allowEmptyElement(String prefix, String localName, String nsURI, boolean allowEmpty)
        {
            return mEmptyElements.contains(localName);
        }
    }
    
    
HTML specific empty element handler. Extends the SetEmptyElementHandler and configures the HTML elements that must be self-closing according to the W3C: http://www.w3.org/TR/html4/index/elements.html 

Note that element name comparison is case-insensitive as required
by HTML specification.
/**
     * HTML specific empty element handler.
     * Extends the {@link SetEmptyElementHandler} and configures
     * the HTML elements that must be self-closing according to the W3C:
     * http://www.w3.org/TR/html4/index/elements.html
     *<p>
     * Note that element name comparison is case-insensitive as required
     * by HTML specification.
     */
    public static class HtmlEmptyElementHandler
        extends SetEmptyElementHandler
    {
        private final static HtmlEmptyElementHandler sInstance = new HtmlEmptyElementHandler();

        public static HtmlEmptyElementHandler getInstance() { return sInstance; }
        
        protected HtmlEmptyElementHandler()
        {
            super(new TreeSet<String>(String.CASE_INSENSITIVE_ORDER));
            mEmptyElements.add("area");
            mEmptyElements.add("base");
            mEmptyElements.add("basefont");
            mEmptyElements.add("br");
            mEmptyElements.add("col");
            mEmptyElements.add("frame");
            mEmptyElements.add("hr");
            mEmptyElements.add("input");
            mEmptyElements.add("img");
            mEmptyElements.add("isindex");
            mEmptyElements.add("link");
            mEmptyElements.add("meta");
            mEmptyElements.add("param");
        }
    }
}