1/*
2 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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24 */
25/*
26 * Copyright (C) 2004-2012
27 *
28 * Permission is hereby granted, free of charge, to any person obtaining a copy
29 * of this software and associated documentation files (the "Software"), to deal
30 * in the Software without restriction, including without limitation the rights
31 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
32 * copies of the Software, and to permit persons to whom the Software is
33 * furnished to do so, subject to the following conditions:
34 *
35 * The above copyright notice and this permission notice shall be included in
36 * all copies or substantial portions of the Software.
37 *
38 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
39 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
40 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
41 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
42 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
43 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
44 * THE SOFTWARE.
45 */
46package com.sun.xml.internal.rngom.digested;
47
48import com.sun.xml.internal.rngom.ast.om.ParsedPattern;
49import com.sun.xml.internal.rngom.parse.Parseable;
50import org.xml.sax.Locator;
51
52/**
53 * Base class of all the patterns.
54 *
55 * @author Kohsuke Kawaguchi (kk@kohsuke.org)
56 */
57public abstract class DPattern implements ParsedPattern {
58
59    Locator location;
60    DAnnotation annotation;
61    /**
62     * Used to chain the child patterns in a doubly-linked list.
63     */
64    DPattern next;
65    DPattern prev;
66
67    /**
68     * Returns where the pattern is defined in the source code.
69     */
70    public Locator getLocation() {
71        return location;
72    }
73
74    /**
75     * Returns the annotation associated with it.
76     *
77     * @return may be empty, but never be null.
78     */
79    public DAnnotation getAnnotation() {
80        if (annotation == null) {
81            return DAnnotation.EMPTY;
82        }
83        return annotation;
84    }
85
86    /**
87     * Returns true if this pattern is nullable.
88     *
89     * A nullable pattern is a pattern that can match the empty sequence.
90     */
91    public abstract boolean isNullable();
92
93    public abstract <V> V accept(DPatternVisitor<V> visitor);
94
95    /**
96     * Creates a {@link Parseable} object that reparses this pattern.
97     */
98    public Parseable createParseable() {
99        return new PatternParseable(this);
100    }
101
102    /**
103     * Returns true if this is {@link DElementPattern}.
104     */
105    public final boolean isElement() {
106        return this instanceof DElementPattern;
107    }
108
109    /**
110     * Returns true if this is {@link DAttributePattern}.
111     */
112    public final boolean isAttribute() {
113        return this instanceof DAttributePattern;
114    }
115}
116