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 *

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package com.sun.xml.internal.rngom.digested;

import java.util.HashMap;

import java.util.Iterator;

import java.util.Map;

/**

 *

 * @author Kohsuke Kawaguchi (kk@kohsuke.org)

 */

public class DGrammarPattern extends DPattern implements Iterable<DDefine> {

    private final Map<String,DDefine> patterns = new HashMap<String,DDefine>();

    DPattern start;

    /**

     * Gets the start pattern.

     */

    public DPattern getStart() {

        return start;

    }

    /**

     * Gets the named pattern by its name.

     *

     * @return

     *      null if not found.

     */

    public DDefine get( String name ) {

        return patterns.get(name);

    }

    DDefine getOrAdd( String name ) {

        if(patterns.containsKey(name)) {

            return get(name);

        } else {

            DDefine d = new DDefine(name);

            patterns.put(name,d);

            return d;

        }

    }

    /**

     * Iterates all the {@link DDefine}s in this grammar.

     */

    public Iterator<DDefine> iterator() {

        return patterns.values().iterator();

    }

    public boolean isNullable() {

        return start.isNullable();

    }

    public <V> V accept( DPatternVisitor<V> visitor ) {

        return visitor.onGrammar(this);

    }

}