1/*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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7 * published by the Free Software Foundation.  Oracle designates this
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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).
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24 */
25
26package com.sun.xml.internal.xsom;
27
28import com.sun.xml.internal.xsom.impl.scd.Iterators;
29import com.sun.xml.internal.xsom.impl.scd.ParseException;
30import com.sun.xml.internal.xsom.impl.scd.SCDImpl;
31import com.sun.xml.internal.xsom.impl.scd.SCDParser;
32import com.sun.xml.internal.xsom.impl.scd.Step;
33import com.sun.xml.internal.xsom.impl.scd.TokenMgrError;
34import com.sun.xml.internal.xsom.util.DeferedCollection;
35
36import javax.xml.namespace.NamespaceContext;
37import java.util.Collection;
38import java.util.Iterator;
39import java.util.List;
40
41/**
42 * Schema Component Designator (SCD).
43 *
44 * <p>
45 * SCD for schema is what XPath is for XML. SCD allows you to select a schema component(s)
46 * from a schema component(s).
47 *
48 * <p>
49 * See <a href="http://www.w3.org/TR/2005/WD-xmlschema-ref-20050329/">XML Schema: Component Designators</a>.
50 * This implementation is based on 03/29/2005 working draft.
51 *
52 * @author Kohsuke Kawaguchi
53 */
54public abstract class SCD {
55
56    /**
57     * Parses the string representation of SCD.
58     *
59     * <p>
60     * This method involves parsing the path expression and preparing the in-memory
61     * structure, so this is useful when you plan to use the same SCD against
62     * different context node multiple times.
63     *
64     * <p>
65     * If you want to evaluate SCD just once, use {@link XSComponent#select} methods.
66     *
67     * @param path
68     *      the string representation of SCD, such as "/foo/bar".
69     * @param nsContext
70     *      Its {@link NamespaceContext#getNamespaceURI(String)} is used
71     *      to resolve prefixes in the SCD to the namespace URI.
72     */
73    public static SCD create(String path, NamespaceContext nsContext) throws java.text.ParseException {
74        try {
75            SCDParser p = new SCDParser(path,nsContext);
76            List<?> list = p.RelativeSchemaComponentPath();
77            return new SCDImpl(path,list.toArray(new Step[list.size()]));
78        } catch (TokenMgrError e) {
79            throw setCause(new java.text.ParseException(e.getMessage(), -1 ),e);
80        } catch (ParseException e) {
81            throw setCause(new java.text.ParseException(e.getMessage(), e.currentToken.beginColumn ),e);
82        }
83    }
84
85    private static java.text.ParseException setCause(java.text.ParseException e, Throwable x) {
86        e.initCause(x);
87        return e;
88    }
89
90    /**
91     * Evaluates the SCD against the given context node and
92     * returns the matched nodes.
93     *
94     * @return
95     *      could be empty but never be null.
96     */
97    public final Collection<XSComponent> select(XSComponent contextNode) {
98        return new DeferedCollection<XSComponent>(select(Iterators.singleton(contextNode)));
99    }
100
101    /**
102     * Evaluates the SCD against the whole schema and
103     * returns the matched nodes.
104     *
105     * <p>
106     * This method is here because {@link XSSchemaSet}
107     * doesn't implement {@link XSComponent}.
108     *
109     * @return
110     *      could be empty but never be null.
111     */
112    public final Collection<XSComponent> select(XSSchemaSet contextNode) {
113        return select(contextNode.getSchemas());
114    }
115
116    /**
117     * Evaluates the SCD against the given context node and
118     * returns the matched node.
119     *
120     * @return
121     *      null if the SCD didn't match anything. If the SCD matched more than one node,
122     *      the first one will be returned.
123     */
124    public final XSComponent selectSingle(XSComponent contextNode) {
125        Iterator<XSComponent> r = select(Iterators.singleton(contextNode));
126        if(r.hasNext())     return r.next();
127        return null;
128    }
129
130    /**
131     * Evaluates the SCD against the whole schema set and
132     * returns the matched node.
133     *
134     * @return
135     *      null if the SCD didn't match anything. If the SCD matched more than one node,
136     *      the first one will be returned.
137     */
138    public final XSComponent selectSingle(XSSchemaSet contextNode) {
139        Iterator<XSComponent> r = select(contextNode.iterateSchema());
140        if(r.hasNext())     return r.next();
141        return null;
142    }
143
144    /**
145     * Evaluates the SCD against the given set of context nodes and
146     * returns the matched nodes.
147     *
148     * @param contextNodes
149     *      {@link XSComponent}s that represent the context node against
150     *      which {@link SCD} is evaluated.
151     *
152     * @return
153     *      could be empty but never be null.
154     */
155    public abstract Iterator<XSComponent> select(Iterator<? extends XSComponent> contextNodes);
156
157    /**
158     * Evaluates the SCD against the given set of context nodes and
159     * returns the matched nodes.
160     *
161     * @param contextNodes
162     *      {@link XSComponent}s that represent the context node against
163     *      which {@link SCD} is evaluated.
164     *
165     * @return
166     *      could be empty but never be null.
167     */
168    public final Collection<XSComponent> select(Collection<? extends XSComponent> contextNodes) {
169        return new DeferedCollection<XSComponent>(select(contextNodes.iterator()));
170    }
171
172    /**
173     * Returns the textual SCD representation as given to {@link SCD#create(String, NamespaceContext)}.
174     */
175    public abstract String toString();
176}
177