/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 1999-2003 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Xalan" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, Lotus
* Development Corporation., http://www.lotus.com. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
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;
/**
* <meta name="usage" content="general"/>
* 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.
*/
public class XObject extends Expression implements Serializable, Cloneable
{
/**
* 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)
{
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 <code>DTMIterator</code> from the set which it iterated
* over, releasing any computational resources and placing the iterator
* in the INVALID state. After <code>detach</code> has been invoked,
* calls to <code>nextNode</code> or <code>previousNode</code> 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();
m_obj = 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 <emph>can</emph> 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 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;
}
}