/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /* * $Id: XObject.java 469368 2006-10-31 04:41:36Z minchau $ */ package org.apache.xpath.objects; import java.io.Serializable; import org.apache.xalan.res.XSLMessages; import org.apache.xml.dtm.DTM; import org.apache.xml.dtm.DTMIterator; import org.apache.xml.utils.XMLString; import org.apache.xpath.Expression; import org.apache.xpath.ExpressionOwner; import org.apache.xpath.NodeSetDTM; import org.apache.xpath.XPathContext; import org.apache.xpath.XPathException; import org.apache.xpath.XPathVisitor; import org.apache.xpath.res.XPATHErrorResources; import org.w3c.dom.DocumentFragment; import org.w3c.dom.NodeList; import org.w3c.dom.traversal.NodeIterator; /** * This class represents an XPath object, and is capable of * converting the object to various types, such as a string. * This class acts as the base class to other XPath type objects, * such as XString, and provides polymorphic casting capabilities. * @xsl.usage general */ public class XObject extends Expression implements Serializable, Cloneable { static final long serialVersionUID = -821887098985662951L; /** * The java object which this object wraps. * @serial */ protected Object m_obj; // This may be NULL!!! /** * Create an XObject. */ public XObject(){} /** * Create an XObject. * * @param obj Can be any object, should be a specific type * for derived classes, or null. */ public XObject(Object obj) { setObject(obj); } protected void setObject(Object obj) { m_obj = obj; } /** * For support of literal objects in xpaths. * * @param xctxt The XPath execution context. * * @return This object. * * @throws javax.xml.transform.TransformerException */ public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException { return this; } /** * Specify if it's OK for detach to release the iterator for reuse. * This function should be called with a value of false for objects that are * stored in variables. * Calling this with a value of false on a XNodeSet will cause the nodeset * to be cached. * * @param allowRelease true if it is OK for detach to release this iterator * for pooling. */ public void allowDetachToRelease(boolean allowRelease){} /** * Detaches the DTMIterator from the set which it iterated * over, releasing any computational resources and placing the iterator * in the INVALID state. After detach has been invoked, * calls to nextNode or previousNode will * raise a runtime exception. */ public void detach(){} /** * Forces the object to release it's resources. This is more harsh than * detach(). */ public void destruct() { if (null != m_obj) { allowDetachToRelease(true); detach(); setObject(null); } } /** * Reset for fresh reuse. */ public void reset() { } /** * Directly call the * characters method on the passed ContentHandler for the * string-value. Multiple calls to the * ContentHandler's characters methods may well occur for a single call to * this method. * * @param ch A non-null reference to a ContentHandler. * * @throws org.xml.sax.SAXException */ public void dispatchCharactersEvents(org.xml.sax.ContentHandler ch) throws org.xml.sax.SAXException { xstr().dispatchCharactersEvents(ch); } /** * Create the right XObject based on the type of the object passed. This * function can not make an XObject that exposes DOM Nodes, NodeLists, and * NodeIterators to the XSLT stylesheet as node-sets. * * @param val The java object which this object will wrap. * * @return the right XObject based on the type of the object passed. */ static public XObject create(Object val) { return XObjectFactory.create(val); } /** * Create the right XObject based on the type of the object passed. * This function can make an XObject that exposes DOM Nodes, NodeLists, and * NodeIterators to the XSLT stylesheet as node-sets. * * @param val The java object which this object will wrap. * @param xctxt The XPath context. * * @return the right XObject based on the type of the object passed. */ static public XObject create(Object val, XPathContext xctxt) { return XObjectFactory.create(val, xctxt); } /** Constant for NULL object type */ public static final int CLASS_NULL = -1; /** Constant for UNKNOWN object type */ public static final int CLASS_UNKNOWN = 0; /** Constant for BOOLEAN object type */ public static final int CLASS_BOOLEAN = 1; /** Constant for NUMBER object type */ public static final int CLASS_NUMBER = 2; /** Constant for STRING object type */ public static final int CLASS_STRING = 3; /** Constant for NODESET object type */ public static final int CLASS_NODESET = 4; /** Constant for RESULT TREE FRAGMENT object type */ public static final int CLASS_RTREEFRAG = 5; /** Represents an unresolved variable type as an integer. */ public static final int CLASS_UNRESOLVEDVARIABLE = 600; /** * Tell what kind of class this is. * * @return CLASS_UNKNOWN */ public int getType() { return CLASS_UNKNOWN; } /** * Given a request type, return the equivalent string. * For diagnostic purposes. * * @return type string "#UNKNOWN" + object class name */ public String getTypeString() { return "#UNKNOWN (" + object().getClass().getName() + ")"; } /** * Cast result object to a number. Always issues an error. * * @return 0.0 * * @throws javax.xml.transform.TransformerException */ public double num() throws javax.xml.transform.TransformerException { error(XPATHErrorResources.ER_CANT_CONVERT_TO_NUMBER, new Object[]{ getTypeString() }); //"Can not convert "+getTypeString()+" to a number"); return 0.0; } /** * Cast result object to a number, but allow side effects, such as the * incrementing of an iterator. * * @return numeric value of the string conversion from the * next node in the NodeSetDTM, or NAN if no node was found */ public double numWithSideEffects() throws javax.xml.transform.TransformerException { return num(); } /** * Cast result object to a boolean. Always issues an error. * * @return false * * @throws javax.xml.transform.TransformerException */ public boolean bool() throws javax.xml.transform.TransformerException { error(XPATHErrorResources.ER_CANT_CONVERT_TO_NUMBER, new Object[]{ getTypeString() }); //"Can not convert "+getTypeString()+" to a number"); return false; } /** * Cast result object to a boolean, but allow side effects, such as the * incrementing of an iterator. * * @return True if there is a next node in the nodeset */ public boolean boolWithSideEffects() throws javax.xml.transform.TransformerException { return bool(); } /** * Cast result object to a string. * * @return The string this wraps or the empty string if null */ public XMLString xstr() { return XMLStringFactoryImpl.getFactory().newstr(str()); } /** * Cast result object to a string. * * @return The object as a string */ public String str() { return (m_obj != null) ? m_obj.toString() : ""; } /** * Return the string representation of the object * * * @return the string representation of the object */ public String toString() { return str(); } /** * Cast result object to a result tree fragment. * * @param support XPath context to use for the conversion * * @return the objec as a result tree fragment. */ public int rtf(XPathContext support) { int result = rtf(); if (DTM.NULL == result) { DTM frag = support.createDocumentFragment(); // %OPT% frag.appendTextChild(str()); result = frag.getDocument(); } return result; } /** * Cast result object to a result tree fragment. * * @param support XPath context to use for the conversion * * @return the objec as a result tree fragment. */ public DocumentFragment rtree(XPathContext support) { DocumentFragment docFrag = null; int result = rtf(); if (DTM.NULL == result) { DTM frag = support.createDocumentFragment(); // %OPT% frag.appendTextChild(str()); docFrag = (DocumentFragment)frag.getNode(frag.getDocument()); } else { DTM frag = support.getDTM(result); docFrag = (DocumentFragment)frag.getNode(frag.getDocument()); } return docFrag; } /** * For functions to override. * * @return null */ public DocumentFragment rtree() { return null; } /** * For functions to override. * * @return null */ public int rtf() { return DTM.NULL; } /** * Return a java object that's closest to the representation * that should be handed to an extension. * * @return The object that this class wraps */ public Object object() { return m_obj; } /** * Cast result object to a nodelist. Always issues an error. * * @return null * * @throws javax.xml.transform.TransformerException */ public DTMIterator iter() throws javax.xml.transform.TransformerException { error(XPATHErrorResources.ER_CANT_CONVERT_TO_NODELIST, new Object[]{ getTypeString() }); //"Can not convert "+getTypeString()+" to a NodeList!"); return null; } /** * Get a fresh copy of the object. For use with variables. * * @return This object, unless overridden by subclass. */ public XObject getFresh() { return this; } /** * Cast result object to a nodelist. Always issues an error. * * @return null * * @throws javax.xml.transform.TransformerException */ public NodeIterator nodeset() throws javax.xml.transform.TransformerException { error(XPATHErrorResources.ER_CANT_CONVERT_TO_NODELIST, new Object[]{ getTypeString() }); //"Can not convert "+getTypeString()+" to a NodeList!"); return null; } /** * Cast result object to a nodelist. Always issues an error. * * @return null * * @throws javax.xml.transform.TransformerException */ public NodeList nodelist() throws javax.xml.transform.TransformerException { error(XPATHErrorResources.ER_CANT_CONVERT_TO_NODELIST, new Object[]{ getTypeString() }); //"Can not convert "+getTypeString()+" to a NodeList!"); return null; } /** * Cast result object to a nodelist. Always issues an error. * * @return The object as a NodeSetDTM. * * @throws javax.xml.transform.TransformerException */ public NodeSetDTM mutableNodeset() throws javax.xml.transform.TransformerException { error(XPATHErrorResources.ER_CANT_CONVERT_TO_MUTABLENODELIST, new Object[]{ getTypeString() }); //"Can not convert "+getTypeString()+" to a NodeSetDTM!"); return (NodeSetDTM) m_obj; } /** * Cast object to type t. * * @param t Type of object to cast this to * @param support XPath context to use for the conversion * * @return This object as the given type t * * @throws javax.xml.transform.TransformerException */ public Object castToType(int t, XPathContext support) throws javax.xml.transform.TransformerException { Object result; switch (t) { case CLASS_STRING : result = str(); break; case CLASS_NUMBER : result = new Double(num()); break; case CLASS_NODESET : result = iter(); break; case CLASS_BOOLEAN : result = new Boolean(bool()); break; case CLASS_UNKNOWN : result = m_obj; break; // %TBD% What to do here? // case CLASS_RTREEFRAG : // result = rtree(support); // break; default : error(XPATHErrorResources.ER_CANT_CONVERT_TO_TYPE, new Object[]{ getTypeString(), Integer.toString(t) }); //"Can not convert "+getTypeString()+" to a type#"+t); result = null; } return result; } /** * Tell if one object is less than the other. * * @param obj2 Object to compare this to * * @return True if this object is less than the given object * * @throws javax.xml.transform.TransformerException */ public boolean lessThan(XObject obj2) throws javax.xml.transform.TransformerException { // In order to handle the 'all' semantics of // nodeset comparisons, we always call the // nodeset function. Because the arguments // are backwards, we call the opposite comparison // function. if (obj2.getType() == XObject.CLASS_NODESET) return obj2.greaterThan(this); return this.num() < obj2.num(); } /** * Tell if one object is less than or equal to the other. * * @param obj2 Object to compare this to * * @return True if this object is less than or equal to the given object * * @throws javax.xml.transform.TransformerException */ public boolean lessThanOrEqual(XObject obj2) throws javax.xml.transform.TransformerException { // In order to handle the 'all' semantics of // nodeset comparisons, we always call the // nodeset function. Because the arguments // are backwards, we call the opposite comparison // function. if (obj2.getType() == XObject.CLASS_NODESET) return obj2.greaterThanOrEqual(this); return this.num() <= obj2.num(); } /** * Tell if one object is greater than the other. * * @param obj2 Object to compare this to * * @return True if this object is greater than the given object * * @throws javax.xml.transform.TransformerException */ public boolean greaterThan(XObject obj2) throws javax.xml.transform.TransformerException { // In order to handle the 'all' semantics of // nodeset comparisons, we always call the // nodeset function. Because the arguments // are backwards, we call the opposite comparison // function. if (obj2.getType() == XObject.CLASS_NODESET) return obj2.lessThan(this); return this.num() > obj2.num(); } /** * Tell if one object is greater than or equal to the other. * * @param obj2 Object to compare this to * * @return True if this object is greater than or equal to the given object * * @throws javax.xml.transform.TransformerException */ public boolean greaterThanOrEqual(XObject obj2) throws javax.xml.transform.TransformerException { // In order to handle the 'all' semantics of // nodeset comparisons, we always call the // nodeset function. Because the arguments // are backwards, we call the opposite comparison // function. if (obj2.getType() == XObject.CLASS_NODESET) return obj2.lessThanOrEqual(this); return this.num() >= obj2.num(); } /** * Tell if two objects are functionally equal. * * @param obj2 Object to compare this to * * @return True if this object is equal to the given object * * @throws javax.xml.transform.TransformerException */ public boolean equals(XObject obj2) { // In order to handle the 'all' semantics of // nodeset comparisons, we always call the // nodeset function. if (obj2.getType() == XObject.CLASS_NODESET) return obj2.equals(this); if (null != m_obj) { return m_obj.equals(obj2.m_obj); } else { return obj2.m_obj == null; } } /** * Tell if two objects are functionally not equal. * * @param obj2 Object to compare this to * * @return True if this object is not equal to the given object * * @throws javax.xml.transform.TransformerException */ public boolean notEquals(XObject obj2) throws javax.xml.transform.TransformerException { // In order to handle the 'all' semantics of // nodeset comparisons, we always call the // nodeset function. if (obj2.getType() == XObject.CLASS_NODESET) return obj2.notEquals(this); return !equals(obj2); } /** * Tell the user of an error, and probably throw an * exception. * * @param msg Error message to issue * * @throws javax.xml.transform.TransformerException */ protected void error(String msg) throws javax.xml.transform.TransformerException { error(msg, null); } /** * Tell the user of an error, and probably throw an * exception. * * @param msg Error message to issue * @param args Arguments to use in the message * * @throws javax.xml.transform.TransformerException */ protected void error(String msg, Object[] args) throws javax.xml.transform.TransformerException { String fmsg = XSLMessages.createXPATHMessage(msg, args); // boolean shouldThrow = support.problem(m_support.XPATHPROCESSOR, // m_support.ERROR, // null, // null, fmsg, 0, 0); // if(shouldThrow) { throw new XPathException(fmsg, this); } } /** * XObjects should not normally need to fix up variables. */ public void fixupVariables(java.util.Vector vars, int globalsSize) { // no-op } /** * Cast result object to a string. * * * NEEDSDOC @param fsb * @return The string this wraps or the empty string if null */ public void appendToFsb(org.apache.xml.utils.FastStringBuffer fsb) { fsb.append(str()); } /** * @see org.apache.xpath.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor) */ public void callVisitors(ExpressionOwner owner, XPathVisitor visitor) { assertion(false, "callVisitors should not be called for this object!!!"); } /** * @see Expression#deepEquals(Expression) */ public boolean deepEquals(Expression expr) { if(!isSameClass(expr)) return false; // If equals at the expression level calls deepEquals, I think we're // still safe from infinite recursion since this object overrides // equals. I hope. if(!this.equals((XObject)expr)) return false; return true; } }