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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2015 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.expr;

import net.sf.saxon.om.SequenceIterator;
import net.sf.saxon.tree.iter.UnfailingIterator;
import net.sf.saxon.value.StringValue;

import java.util.StringTokenizer;

/**
 * StringTokenIterator: breaks a string up into tokens,
 * and returns the tokens as a sequence of strings.
 */

public class StringTokenIterator implements UnfailingIterator {

    private String theString;
    /*@Nullable*/ private String delimiters;  // null implies use whitespace as delimiter
    private StringTokenizer tokenizer;

    /**
     * Construct a StringTokenIterator that will break the supplied
     * string into tokens at whitespace boundaries
     *
     * @param string the string to be tokenized
     */

    public StringTokenIterator(String string) {
        theString = string;
        delimiters = null;
        tokenizer = new StringTokenizer(string, " \t\n\r", false);
    }

    /**
     * Construct a StringTokenIterator that will break the supplied
     * string into tokens at any of the delimiter characters included in the
     * delimiter string.
     *
     * @param string     the string to be tokenized
     * @param delimiters the characters that are recognized as token separators
     */

    public StringTokenIterator(String string, String delimiters) {
        theString = string;
        this.delimiters = delimiters;
        tokenizer = new StringTokenizer(string, delimiters, false);
    }

    public StringValue next() {
        if (tokenizer.hasMoreElements()) {
            String current = (String) tokenizer.nextElement();
            return new StringValue(current);
        } else {
            return null;
        }
    }

    public void close() {
    }

    /*@NotNull*/
    public StringTokenIterator getAnother() {
        if (delimiters == null) {
            return new StringTokenIterator(theString);
        } else {
            return new StringTokenIterator(theString, delimiters);
        }
    }

    /**
     * Get properties of this iterator, as a bit-significant integer.
     *
     * @return the properties of this iterator. This will be some combination of
     *         properties such as {@link SequenceIterator#GROUNDED}, {@link SequenceIterator#LAST_POSITION_FINDER},
     *         and {@link SequenceIterator#LOOKAHEAD}. It is always
     *         acceptable to return the value zero, indicating that there are no known special properties.
     *         It is acceptable for the properties of the iterator to change depending on its state.
     */

    public int getProperties() {
        return 0;
    }
}