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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2013 Saxonica Limited.
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
package net.sf.saxon.event;
import org.xml.sax.Locator;
import java.util.Stack;
/**
* Implementation of Locator, used to supply location information to the ContentHandler.
*
* When the ContentHandler is used to receive the results of a query or stylesheet,
* the information supplied by the standard methods such as {@link #getSystemId} and
* {@link #getLineNumber} relates to the position of the expression/instruction in the stylesheet
* or query that caused the relevant nodes to be output.
*
* If the ContentHandler is used in other contexts, for example as the destination of an
* IdentityTransformer, the information reflects the position in the source document.
*
* If the output property saxon:supply-source-locator was set to the
* value "yes" (which in turn requires that tracing was enabled at compile time), the Locator will
* also contain information about the current location in the source document (specifically, the position
* of the context node). This will not always be 100% accurate, since there is some buffering of events
* in the output pipeline: it reflects the context node at the time the event reaches the ContentHandler,
* which may not be the same as the context node at the time the relevant instruction was executed;
* however, it still provides some information that may be useful for diagnostics.
*/
public class ContentHandlerProxyLocator implements Locator {
private ContentHandlerProxy parent = null;
/**
* Create the Locator for a ContentHandlerProxy
* @param parent the ContentHandlerProxy
*/
public ContentHandlerProxyLocator(ContentHandlerProxy parent) {
this.parent = parent;
}
// previously ContentHandlerProxy implemented Locator directly. However, this caused a clash
// over the semantics of getSystemId(), which is inherited from both Receiver and Locator.
// The getSystemId() method in the Receiver interface identifies the URI of the document represented
// by the event stream. The getSystemId() method in this class typically returns the URI of the stylesheet
// or query module that generated the event.
/**
* Get the Public ID
* @return null (always)
*/
public String getPublicId() {
return null;
}
/**
* Get the System ID
* @return the system ID giving the location in the query or stylesheet of the most recent event notified
*/
public String getSystemId() {
final LocationProvider locationProvider = parent.getLocationProvider();
if (locationProvider == null) {
return null;
} else {
return locationProvider.getSystemId(parent.getCurrentLocationId());
}
}
/**
* Get the line number
* @return the line number giving the location of the most recent event notified
*/
public int getLineNumber() {
final LocationProvider locationProvider = parent.getLocationProvider();
if (locationProvider == null) {
return -1;
} else {
return locationProvider.getLineNumber(parent.getCurrentLocationId());
}
}
/**
* Get the column number
* @return -1 (always)
*/
public int getColumnNumber() {
return -1;
}
/**
* Get the current item stack. This is a Stack, whose members are objects of class
* {@link net.sf.saxon.om.Item}. The top item in the stack is the context node or atomic value; items
* further down the stack represent previous context node or atomic value
* @return the stack of context items
*/
/*@Nullable*/ public Stack getContextItemStack() {
final ContentHandlerProxy.ContentHandlerProxyTraceListener traceListener = parent.getTraceListener();
if (traceListener == null) {
return null;
} else {
return traceListener.getContextItemStack();
}
}
}