package org.apache.axis.message;

import org.xml.sax.Attributes;

/**
 * Null implementation of the Attributes interface.
 *
 * @author David Megginson
 * @author Sam Ruby <rubys@us.ibm.com>
 */
public class NullAttributes implements Attributes {

    public static final NullAttributes singleton = new NullAttributes();

    ////////////////////////////////////////////////////////////////////
    // Implementation of org.xml.sax.Attributes.
    ////////////////////////////////////////////////////////////////////


    /**
     * Return the number of attributes in the list.
     *
     * @return The number of attributes in the list.
     * @see org.xml.sax.Attributes#getLength
     */
    public int getLength () {
        return 0;
    }


    /**
     * Return an attribute's Namespace URI.
     *
     * @param index The attribute's index (zero-based).
     * @return The Namespace URI, the empty string if none is
     *         available, or null if the index is out of range.
     * @see org.xml.sax.Attributes#getURI
     */
    public String getURI (int index) {
        return null;
    }


    /**
     * Return an attribute's local name.
     *
     * @param index The attribute's index (zero-based).
     * @return The attribute's local name, the empty string if 
     *         none is available, or null if the index if out of range.
     * @see org.xml.sax.Attributes#getLocalName
     */
    public String getLocalName (int index) {
        return null;
    }


    /**
     * Return an attribute's qualified (prefixed) name.
     *
     * @param index The attribute's index (zero-based).
     * @return The attribute's qualified name, the empty string if 
     *         none is available, or null if the index is out of bounds.
     * @see org.xml.sax.Attributes#getQName
     */
    public String getQName (int index) {
        return null;
    }


    /**
     * Return an attribute's type by index.
     *
     * @param index The attribute's index (zero-based).
     * @return The attribute's type, "CDATA" if the type is unknown, or null
     *         if the index is out of bounds.
     * @see org.xml.sax.Attributes#getType(int)
     */
    public String getType (int index) {
        return null;
    }


    /**
     * Return an attribute's value by index.
     *
     * @param index The attribute's index (zero-based).
     * @return The attribute's value or null if the index is out of bounds.
     * @see org.xml.sax.Attributes#getValue(int)
     */
    public String getValue (int index) {
        return null;
    }


    /**
     * Look up an attribute's index by Namespace name.
     *
     * <p>In many cases, it will be more efficient to look up the name once and
     * use the index query methods rather than using the name query methods
     * repeatedly.</p>
     *
     * @param uri The attribute's Namespace URI, or the empty
     *        string if none is available.
     * @param localName The attribute's local name.
     * @return The attribute's index, or -1 if none matches.
     * @see org.xml.sax.Attributes#getIndex(java.lang.String,java.lang.String)
     */
    public int getIndex (String uri, String localName) {
        return -1;
    }


    /**
     * Look up an attribute's index by qualified (prefixed) name.
     *
     * @param qName The qualified name.
     * @return The attribute's index, or -1 if none matches.
     * @see org.xml.sax.Attributes#getIndex(java.lang.String)
     */
    public int getIndex (String qName) {
        return -1;
    }


    /**
     * Look up an attribute's type by Namespace-qualified name.
     *
     * @param uri The Namespace URI, or the empty string for a name
     *        with no explicit Namespace URI.
     * @param localName The local name.
     * @return The attribute's type, or null if there is no
     *         matching attribute.
     * @see org.xml.sax.Attributes#getType(java.lang.String,java.lang.String)
     */
    public String getType (String uri, String localName) {
        return null;
    }


    /**
     * Look up an attribute's type by qualified (prefixed) name.
     *
     * @param qName The qualified name.
     * @return The attribute's type, or null if there is no
     *         matching attribute.
     * @see org.xml.sax.Attributes#getType(java.lang.String)
     */
    public String getType (String qName) {
        return null;
    }


    /**
     * Look up an attribute's value by Namespace-qualified name.
     *
     * @param uri The Namespace URI, or the empty string for a name
     *        with no explicit Namespace URI.
     * @param localName The local name.
     * @return The attribute's value, or null if there is no
     *         matching attribute.
     * @see org.xml.sax.Attributes#getValue(java.lang.String,java.lang.String)
     */
    public String getValue (String uri, String localName) {
        return null;
    }


    /**
     * Look up an attribute's value by qualified (prefixed) name.
     *
     * @param qName The qualified name.
     * @return The attribute's value, or null if there is no
     *         matching attribute.
     * @see org.xml.sax.Attributes#getValue(java.lang.String)
     */
    public String getValue (String qName) {
        return null;
    }
}