1/* 2 * Copyright (c) 1997, 2012, 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 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