////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2018 Saxonica Limited.
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

package net.sf.saxon.om;

import java.util.Iterator;

/**
 * Abstract class that supports lookup of a lexical QName to get the expanded QName.
 */

public interface NamespaceResolver {

    /**
     * Get the namespace URI corresponding to a given prefix. Return null
     * if the prefix is not in scope.
     *
     * @param prefix     the namespace prefix. May be the zero-length string, indicating
     *                   that there is no prefix. This indicates either the default namespace or the
     *                   null namespace, depending on the value of useDefault.
     * @param useDefault true if the default namespace is to be used when the
     *                   prefix is "". If false, the method returns "" when the prefix is "". The default
     *                   namespace is a property of the NamespaceResolver; in general it corresponds to
     *                   the "default namespace for elements and types", but that cannot be assumed.
     * @return the uri for the namespace, or null if the prefix is not in scope.
     *         The "null namespace" is represented by the pseudo-URI "".
     */

    /*@Nullable*/
    String getURIForPrefix(String prefix, boolean useDefault);

    /**
     * Get an iterator over all the prefixes declared in this namespace context. This will include
     * the default namespace (prefix="") and the XML namespace where appropriate
     *
     * @return an iterator over all the prefixes for which a namespace binding exists, including
     *         the zero-length string to represent the null/absent prefix if it is bound
     */

    Iterator<String> iteratePrefixes();

}

