/*
* reserved comment block
* DO NOT REMOVE OR ALTER!
*/
/*
* Copyright 1999-2004 The Apache Software Foundation.
*
* Licensed 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
*
*
* 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: Expression.java,v 1.2.4.2 2005/09/14 19:50:20 jeffsuttor Exp $
*/
/**
* This abstract class serves as the base for all expression objects. An
* Expression can be executed to return a {@link com.sun.org.apache.xpath.internal.objects.XObject},
* normally has a location within a document or DOM, can send error and warning
* events, and normally do not hold state and are meant to be immutable once
* construction has completed. An exception to the immutibility rule is iterators
* and walkers, which must be cloned in order to be used -- the original must
* still be immutable.
*/
{
/**
* The location where this expression was built from. Need for diagnostic
* messages. May be null.
* @serial
*/
/**
* Tell if this expression or it's subexpressions can traverse outside
* the current subtree.
*
* @return true if traversal outside the context node's subtree can occur.
*/
public boolean canTraverseOutsideSubtree()
{
return false;
}
// /**
// * Set the location where this expression was built from.
// *
// *
// * @param locator the location where this expression was built from, may be
// * null.
// */
// public void setSourceLocator(SourceLocator locator)
// {
// m_slocator = locator;
// }
/**
* Execute an expression in the XPath runtime context, and return the
* result of the expression.
*
*
* @param xctxt The XPath runtime context.
* @param currentNode The currentNode.
*
* @return The result of the expression in the form of a <code>XObject</code>.
*
* @throws javax.xml.transform.TransformerException if a runtime exception
* occurs.
*/
{
// For now, the current node is already pushed.
}
/**
* Execute an expression in the XPath runtime context, and return the
* result of the expression.
*
*
* @param xctxt The XPath runtime context.
* @param currentNode The currentNode.
* @param dtm The DTM of the current node.
* @param expType The expanded type ID of the current node.
*
* @return The result of the expression in the form of a <code>XObject</code>.
*
* @throws javax.xml.transform.TransformerException if a runtime exception
* occurs.
*/
{
// For now, the current node is already pushed.
}
/**
* Execute an expression in the XPath runtime context, and return the
* result of the expression.
*
*
* @param xctxt The XPath runtime context.
*
* @return The result of the expression in the form of a <code>XObject</code>.
*
* @throws javax.xml.transform.TransformerException if a runtime exception
* occurs.
*/
/**
* Execute an expression in the XPath runtime context, and return the
* result of the expression, but tell that a "safe" object doesn't have
* to be returned. The default implementation just calls execute(xctxt).
*
*
* @param xctxt The XPath runtime context.
* @param destructiveOK true if a "safe" object doesn't need to be returned.
*
* @return The result of the expression in the form of a <code>XObject</code>.
*
* @throws javax.xml.transform.TransformerException if a runtime exception
* occurs.
*/
{
}
/**
* Evaluate expression to a number.
*
*
* @param xctxt The XPath runtime context.
* @return The expression evaluated as a double.
*
* @throws javax.xml.transform.TransformerException
*/
{
}
/**
* Evaluate expression to a boolean.
*
*
* @param xctxt The XPath runtime context.
* @return false
*
* @throws javax.xml.transform.TransformerException
*/
{
}
/**
* Cast result object to a string.
*
*
* @param xctxt The XPath runtime context.
* @return The string this wraps or the empty string if null
*
* @throws javax.xml.transform.TransformerException
*/
{
}
/**
* Tell if the expression is a nodeset expression. In other words, tell
* if you can execute {@link #asNode(XPathContext) asNode} without an exception.
* @return true if the expression can be represented as a nodeset.
*/
public boolean isNodesetExpr()
{
return false;
}
/**
* Return the first node out of the nodeset, if this expression is
* a nodeset expression.
* @param xctxt The XPath runtime context.
* @return the first node out of the nodeset, or DTM.NULL.
*
* @throws javax.xml.transform.TransformerException
*/
{
}
/**
* Given an select expression and a context, evaluate the XPath
* and return the resulting iterator.
*
* @param xctxt The execution context.
* @param contextNode The node that "." expresses.
*
*
* @return A valid DTMIterator.
* @throws TransformerException thrown if the active ProblemListener decides
* the error condition is severe enough to halt processing.
*
* @throws javax.xml.transform.TransformerException
* @xsl.usage experimental
*/
{
try
{
}
finally
{
}
}
/**
* Given an select expression and a context, evaluate the XPath
* and return the resulting iterator, but do not clone.
*
* @param xctxt The execution context.
* @param contextNode The node that "." expresses.
*
*
* @return A valid DTMIterator.
* @throws TransformerException thrown if the active ProblemListener decides
* the error condition is severe enough to halt processing.
*
* @throws javax.xml.transform.TransformerException
* @xsl.usage experimental
*/
{
try
{
}
finally
{
}
}
/**
* Execute an expression in the XPath runtime context, and return the
* result of the expression.
*
*
* @param xctxt The XPath runtime context.
* NEEDSDOC @param handler
*
* @return The result of the expression in the form of a <code>XObject</code>.
*
* @throws javax.xml.transform.TransformerException if a runtime exception
* occurs.
* @throws org.xml.sax.SAXException
*/
public void executeCharsToContentHandler(
{
}
/**
* Tell if this expression returns a stable number that will not change during
* iterations within the expression. This is used to determine if a proximity
* position predicate can indicate that no more searching has to occur.
*
*
* @return true if the expression represents a stable number.
*/
public boolean isStableNumber()
{
return false;
}
/**
* This function is used to fixup variables from QNames to stack frame
* indexes at stylesheet build time.
* @param vars List of QNames that correspond to variables. This list
* should be searched backwards for the first qualified name that
* corresponds to the variable reference qname. The position of the
* QName in the vector from the start of the vector will be its position
* in the stack frame (but variables above the globalsTop value will need
* to be offset to the current stack frame).
* NEEDSDOC @param globalsSize
*/
/**
* Compare this object with another object and see
* if they are equal, include the sub heararchy.
*
* @param expr Another expression object.
* @return true if this objects class and the expr
* object's class are the same, and the data contained
* within both objects are considered equal.
*/
/**
* This is a utility method to tell if the passed in
* class is the same class as this. It is to be used by
* the deepEquals method. I'm bottlenecking it here
* because I'm not totally confident that comparing the
* class objects is the best way to do this.
* @return true of the passed in class is the exact same
* class as this class.
*/
{
return false;
}
/**
* Warn the user of an problem.
*
* @param xctxt The XPath runtime context.
* @param msg An error msgkey that corresponds to one of the conststants found
* in {@link com.sun.org.apache.xpath.internal.res.XPATHErrorResources}, which is
* a key for a format string.
* @param args An array of arguments represented in the format string, which
* may be null.
*
* @throws TransformerException if the current ErrorListoner determines to
* throw an exception.
*
* @throws javax.xml.transform.TransformerException
*/
{
{
// TO DO: Need to get stylesheet Locator from here.
}
}
/**
* Tell the user of an assertion error, and probably throw an
* exception.
*
* @param b If false, a runtime exception will be thrown.
* @param msg The assertion message, which should be informative.
*
* @throws RuntimeException if the b argument is false.
*
* @throws javax.xml.transform.TransformerException
*/
{
if (!b)
{
throw new RuntimeException(fMsg);
}
}
/**
* Tell the user of an error, and probably throw an
* exception.
*
* @param xctxt The XPath runtime context.
* @param msg An error msgkey that corresponds to one of the constants found
* in {@link com.sun.org.apache.xpath.internal.res.XPATHErrorResources}, which is
* a key for a format string.
* @param args An array of arguments represented in the format string, which
* may be null.
*
* @throws TransformerException if the current ErrorListoner determines to
* throw an exception.
*
* @throws javax.xml.transform.TransformerException
*/
{
{
}
}
/**
* Get the first non-Expression parent of this node.
* @return null or first ancestor that is not an Expression.
*/
{
return parent;
}
//=============== ExpressionNode methods ================
/** This pair of methods are used to inform the node of its
parent. */
{
assertion(n != this, "Can not parent an expression to itself!");
m_parent = n;
}
{
return m_parent;
}
/** This method tells the node to add its argument to the node's
list of children. */
{
assertion(false, "exprAddChild method not implemented!");
}
/** This method returns a child node. The children are numbered
from zero, left to right. */
{
return null;
}
/** Return the number of children the node has. */
public int exprGetNumChildren()
{
return 0;
}
//=============== SourceLocator methods ================
/**
* Return the public identifier for the current document event.
*
* <p>The return value is the public identifier of the document
* entity or of the external parsed entity in which the markup that
* triggered the event appears.</p>
*
* @return A string containing the public identifier, or
* null if none is available.
* @see #getSystemId
*/
{
return null;
return m_parent.getPublicId();
}
/**
* Return the system identifier for the current document event.
*
* <p>The return value is the system identifier of the document
* entity or of the external parsed entity in which the markup that
* triggered the event appears.</p>
*
* <p>If the system identifier is a URL, the parser must resolve it
* fully before passing it to the application.</p>
*
* @return A string containing the system identifier, or null
* if none is available.
* @see #getPublicId
*/
{
return null;
return m_parent.getSystemId();
}
/**
* Return the line number where the current document event ends.
*
* <p><strong>Warning:</strong> The return value from the method
* is intended only as an approximation for the sake of error
* reporting; it is not intended to provide sufficient information
* to edit the character content of the original XML document.</p>
*
* <p>The return value is an approximation of the line number
* in the document entity or external parsed entity where the
* markup that triggered the event appears.</p>
*
* @return The line number, or -1 if none is available.
* @see #getColumnNumber
*/
public int getLineNumber()
{
return 0;
return m_parent.getLineNumber();
}
/**
* Return the character position where the current document event ends.
*
* <p><strong>Warning:</strong> The return value from the method
* is intended only as an approximation for the sake of error
* reporting; it is not intended to provide sufficient information
* to edit the character content of the original XML document.</p>
*
* <p>The return value is an approximation of the column number
* in the document entity or external parsed entity where the
* markup that triggered the event appears.</p>
*
* @return The column number, or -1 if none is available.
* @see #getLineNumber
*/
public int getColumnNumber()
{
return 0;
return m_parent.getColumnNumber();
}
}