19f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson/* 29f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Licensed to the Apache Software Foundation (ASF) under one 39f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * or more contributor license agreements. See the NOTICE file 49f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * distributed with this work for additional information 59f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * regarding copyright ownership. The ASF licenses this file 69f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * to you under the Apache License, Version 2.0 (the "License"); 79f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * you may not use this file except in compliance with the License. 89f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * You may obtain a copy of the License at 99f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 109f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * http://www.apache.org/licenses/LICENSE-2.0 119f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 129f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Unless required by applicable law or agreed to in writing, software 139f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * distributed under the License is distributed on an "AS IS" BASIS, 149f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 159f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * See the License for the specific language governing permissions and 169f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * limitations under the License. 179f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 189f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson/* 199f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * $Id: XNull.java 468655 2006-10-28 07:12:06Z minchau $ 209f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 219f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonpackage org.apache.xpath.objects; 229f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 239f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xml.dtm.DTM; 249f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xpath.XPathContext; 259f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 269f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson/** 279f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * This class represents an XPath null object, and is capable of 289f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * converting the null to other types, such as a string. 299f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @xsl.usage general 309f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 319f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonpublic class XNull extends XNodeSet 329f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson{ 339f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson static final long serialVersionUID = -6841683711458983005L; 349f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 359f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 369f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Create an XObject. 379f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 389f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public XNull() 399f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 409f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson super(); 419f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 429f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 439f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 449f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Tell what kind of class this is. 459f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 469f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return type CLASS_NULL 479f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 489f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public int getType() 499f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 509f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return CLASS_NULL; 519f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 529f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 539f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 549f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Given a request type, return the equivalent string. 559f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * For diagnostic purposes. 569f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 579f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return type string "#CLASS_NULL" 589f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 599f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public String getTypeString() 609f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 619f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return "#CLASS_NULL"; 629f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 639f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 649f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 659f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Cast result object to a number. 669f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 679f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return 0.0 689f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 699f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 709f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public double num() 719f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 729f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return 0.0; 739f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 749f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 759f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 769f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Cast result object to a boolean. 779f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 789f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return false 799f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 809f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean bool() 819f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 829f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return false; 839f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 849f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 859f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 869f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Cast result object to a string. 879f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 889f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return empty string "" 899f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 909f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public String str() 919f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 929f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return ""; 939f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 949f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 959f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 969f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Cast result object to a result tree fragment. 979f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 989f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param support XPath context to use for the conversion 999f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 1009f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return The object as a result tree fragment. 1019f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 1029f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public int rtf(XPathContext support) 1039f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 1049f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson // DTM frag = support.createDocumentFragment(); 1059f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson // %REVIEW% 1069f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return DTM.NULL; 1079f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1089f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 1099f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson// /** 1109f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson// * Cast result object to a nodelist. 1119f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson// * 1129f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson// * @return null 1139f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson// */ 1149f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson// public DTMIterator iter() 1159f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson// { 1169f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson// return null; 1179f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson// } 1189f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 1199f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 1209f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Tell if two objects are functionally equal. 1219f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 1229f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param obj2 Object to compare this to 1239f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 1249f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return True if the given object is of type CLASS_NULL 1259f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 1269f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean equals(XObject obj2) 1279f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 1289f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return obj2.getType() == CLASS_NULL; 1299f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1309f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson} 131