1 /*

     2  * Copyright (c) 1997, 2010, 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

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    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

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package com.sun.xml.internal.xsom;

    27 

    28 import com.sun.xml.internal.xsom.impl.scd.Iterators;

    29 import com.sun.xml.internal.xsom.impl.scd.ParseException;

    30 import com.sun.xml.internal.xsom.impl.scd.SCDImpl;

    31 import com.sun.xml.internal.xsom.impl.scd.SCDParser;

    32 import com.sun.xml.internal.xsom.impl.scd.Step;

    33 import com.sun.xml.internal.xsom.impl.scd.TokenMgrError;

    34 import com.sun.xml.internal.xsom.util.DeferedCollection;

    35 

    36 import javax.xml.namespace.NamespaceContext;

    37 import java.util.Collection;

    38 import java.util.Iterator;

    39 import 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  */

    54 public 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 }