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package org.xml.sax;

/**

 * Interface for a list of XML attributes.

 *

 * <p>This interface allows access to a list of attributes in

 * three different ways:</p>

 *

 * <ol>

 * <li>by attribute index;</li>

 * <li>by Namespace-qualified name; or</li>

 * <li>by qualified (prefixed) name.</li>

 * </ol>

 *

 * <p>The list will not contain attributes that were declared

 * #IMPLIED but not specified in the start tag.  It will also not

 * contain attributes used as Namespace declarations (xmlns*) unless

 * the <code>http://xml.org/sax/features/namespace-prefixes</code>

 * feature is set to <var>true</var> (it is <var>false</var> by

 * default).

 * Because SAX2 conforms to the original "Namespaces in XML"

 * recommendation, it normally does not

 * give namespace declaration attributes a namespace URI.

 * </p>

 *

 * <p>Some SAX2 parsers may support using an optional feature flag

 * (<code>http://xml.org/sax/features/xmlns-uris</code>) to request

 * that those attributes be given URIs, conforming to a later

 * backwards-incompatible revision of that recommendation.  (The

 * attribute's "local name" will be the prefix, or "xmlns" when

 * defining a default element namespace.)  For portability, handler

 * code should always resolve that conflict, rather than requiring

 * parsers that can change the setting of that feature flag.  </p>

 *

 * <p>If the namespace-prefixes feature (see above) is

 * <var>false</var>, access by qualified name may not be available; if

 * the <code>http://xml.org/sax/features/namespaces</code> feature is

 * <var>false</var>, access by Namespace-qualified names may not be

 * available.</p>

 *

 * <p>This interface replaces the now-deprecated SAX1 {@link

 * org.xml.sax.AttributeList AttributeList} interface, which does not

 * contain Namespace support.  In addition to Namespace support, it

 * adds the <var>getIndex</var> methods (below).</p>

 *

 * <p>The order of attributes in the list is unspecified, and will

 * vary from implementation to implementation.</p>

 *

 * @since 1.4, SAX 2.0

 * @author David Megginson

 * @see org.xml.sax.helpers.AttributesImpl

 * @see org.xml.sax.ext.DeclHandler#attributeDecl

 */

public interface Attributes

{

    ////////////////////////////////////////////////////////////////////

    // Indexed access.

    ////////////////////////////////////////////////////////////////////

    /**

     * Return the number of attributes in the list.

     *

     * <p>Once you know the number of attributes, you can iterate

     * through the list.</p>

     *

     * @return The number of attributes in the list.

     * @see #getURI(int)

     * @see #getLocalName(int)

     * @see #getQName(int)

     * @see #getType(int)

     * @see #getValue(int)

     */

    public abstract int getLength ();

    /**

     * Look up an attribute's Namespace URI by index.

     *

     * @param index The attribute index (zero-based).

     * @return The Namespace URI, or the empty string if none

     *         is available, or null if the index is out of

     *         range.

     * @see #getLength

     */

    public abstract String getURI (int index);

    /**

     * Look up an attribute's local name by index.

     *

     * @param index The attribute index (zero-based).

     * @return The local name, or the empty string if Namespace

     *         processing is not being performed, or null

     *         if the index is out of range.

     * @see #getLength

     */

    public abstract String getLocalName (int index);

    /**

     * Look up an attribute's XML qualified (prefixed) name by index.

     *

     * @param index The attribute index (zero-based).

     * @return The XML qualified name, or the empty string

     *         if none is available, or null if the index

     *         is out of range.

     * @see #getLength

     */

    public abstract String getQName (int index);

    /**

     * Look up an attribute's type by index.

     *

     * <p>The attribute type is one of the strings "CDATA", "ID",

     * "IDREF", "IDREFS", "NMTOKEN", "NMTOKENS", "ENTITY", "ENTITIES",

     * or "NOTATION" (always in upper case).</p>

     *

     * <p>If the parser has not read a declaration for the attribute,

     * or if the parser does not report attribute types, then it must

     * return the value "CDATA" as stated in the XML 1.0 Recommendation

     * (clause 3.3.3, "Attribute-Value Normalization").</p>

     *

     * <p>For an enumerated attribute that is not a notation, the

     * parser will report the type as "NMTOKEN".</p>

     *

     * @param index The attribute index (zero-based).

     * @return The attribute's type as a string, or null if the

     *         index is out of range.

     * @see #getLength

     */

    public abstract String getType (int index);

    /**

     * Look up an attribute's value by index.

     *

     * <p>If the attribute value is a list of tokens (IDREFS,

     * ENTITIES, or NMTOKENS), the tokens will be concatenated

     * into a single string with each token separated by a

     * single space.</p>

     *

     * @param index The attribute index (zero-based).

     * @return The attribute's value as a string, or null if the

     *         index is out of range.

     * @see #getLength

     */

    public abstract String getValue (int index);

    ////////////////////////////////////////////////////////////////////

    // Name-based query.

    ////////////////////////////////////////////////////////////////////

    /**

     * Look up the index of an attribute by Namespace name.

     *

     * @param uri The Namespace URI, or the empty string if

     *        the name has no Namespace URI.

     * @param localName The attribute's local name.

     * @return The index of the attribute, or -1 if it does not

     *         appear in the list.

     */

    public int getIndex (String uri, String localName);

    /**

     * Look up the index of an attribute by XML qualified (prefixed) name.

     *

     * @param qName The qualified (prefixed) name.

     * @return The index of the attribute, or -1 if it does not

     *         appear in the list.

     */

    public int getIndex (String qName);

    /**

     * Look up an attribute's type by Namespace name.

     *

     * <p>See {@link #getType(int) getType(int)} for a description

     * of the possible types.</p>

     *

     * @param uri The Namespace URI, or the empty String if the

     *        name has no Namespace URI.

     * @param localName The local name of the attribute.

     * @return The attribute type as a string, or null if the

     *         attribute is not in the list or if Namespace

     *         processing is not being performed.

     */

    public abstract String getType (String uri, String localName);

    /**

     * Look up an attribute's type by XML qualified (prefixed) name.

     *

     * <p>See {@link #getType(int) getType(int)} for a description

     * of the possible types.</p>

     *

     * @param qName The XML qualified name.

     * @return The attribute type as a string, or null if the

     *         attribute is not in the list or if qualified names

     *         are not available.

     */

    public abstract String getType (String qName);

    /**

     * Look up an attribute's value by Namespace name.

     *

     * <p>See {@link #getValue(int) getValue(int)} for a description

     * of the possible values.</p>

     *

     * @param uri The Namespace URI, or the empty String if the

     *        name has no Namespace URI.

     * @param localName The local name of the attribute.

     * @return The attribute value as a string, or null if the

     *         attribute is not in the list.

     */

    public abstract String getValue (String uri, String localName);

    /**

     * Look up an attribute's value by XML qualified (prefixed) name.

     *

     * <p>See {@link #getValue(int) getValue(int)} for a description

     * of the possible values.</p>

     *

     * @param qName The XML qualified name.

     * @return The attribute value as a string, or null if the

     *         attribute is not in the list or if qualified names

     *         are not available.

     */

    public abstract String getValue (String qName);

}

// end of Attributes.java