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package org.codehaus.stax2;

import javax.xml.stream.Location;
import javax.xml.stream.XMLStreamException;

/**
 * Interface that specifies additional access methods for accessing
 * full location information of an input location within a stream reader.
 * Access interface may be directly implemented by the reader, or by
 * another (reusable or per-call-instantiated) helper object.
 *

* Note: instances of LocationInfo are only guaranteed to persist as long * as the (stream) reader points to the current element (whatever it is). * After next call to streamReader.next, it it possible that * the previously accessed LocationInfo points to the old information, new * information, or may even contain just garbage. That is, for each new * event, getLocationInfo should be called separately. */ public interface LocationInfo { /* ///////////////////////////////////////////////////// // Low-level extended "raw" location access methods ///////////////////////////////////////////////////// */ /** * Method that can be used to get exact byte offset (number of bytes * read from the stream right before getting to this location) in the * stream that is pointed to by this reader, right before the start * of the current event. *

* Note: this value MAY be the same as the one returned by * {@link #getStartingCharOffset}, but usually only for single-byte * character streams (Ascii, ISO-Latin). * * @return Byte offset (== number of bytes reader so far) within the * underlying stream, if the stream and stream reader are able to * provide this (separate from the character offset, for variable-byte * encodings); -1 if not. */ public long getStartingByteOffset(); /** * Method that can be used to get exact character offset (number of chars * read from the stream right before getting to this location) in the * stream that is pointed to by this reader, right before the start * of the current event. *

* Note: this value MAY be the same as the one returned by * {@link #getStartingByteOffset}; this is the case for single-byte * character streams (Ascii, ISO-Latin), as well as for streams for * which byte offset information is not available (Readers, Strings). * * @return Character offset (== number of bytes reader so far) within the * underlying stream, if the stream and stream reader are able to * provide this (separate from byte offset, for variable-byte * encodings); -1 if not. */ public long getStartingCharOffset(); /** * Method that can be used to get exact byte offset (number of bytes * read from the stream right before getting to this location) in the * stream that is pointed to by this reader, right after the end * of the current event. *

* Note: this value MAY be the same as the one returned by * {@link #getEndingCharOffset}, but usually only for single-byte * character streams (Ascii, ISO-Latin). *

* Note: for lazy-loading implementations, calling this method may * require the underlying stream to be advanced and contents parsed; * this is why it is possible that an exception be thrown. * * @return Byte offset (== number of bytes reader so far) within the * underlying stream, if the stream and stream reader are able to * provide this (separate from the character offset, for variable-byte * encodings); -1 if not. */ public long getEndingByteOffset() throws XMLStreamException; /** * Method that can be used to get exact character offset (number of chars * read from the stream right before getting to this location) in the * stream that is pointed to by this reader, right after the end * of the current event. *

* Note: this value MAY be the same as the one returned by * {@link #getEndingByteOffset}; this is the case for single-byte * character streams (Ascii, ISO-Latin), as well as for streams for * which byte offset information is not available (Readers, Strings). *

* Note: for lazy-loading implementations, calling this method may * require the underlying stream to be advanced and contents parsed; * this is why it is possible that an exception be thrown. * * @return Character offset (== number of bytes reader so far) within the * underlying stream, if the stream and stream reader are able to * provide this (separate from byte offset, for variable-byte * encodings); -1 if not. */ public long getEndingCharOffset() throws XMLStreamException; /* ///////////////////////////////////////////////////// // Object-oriented location access methods ///////////////////////////////////////////////////// */ // // // Existing method from XMLStreamReader: public Location getLocation(); // // // New methods: /** * An optional method that either returns the location object that points the * starting position of the current event, or null if implementation * does not keep track of it (some may return only end location; and * some no location at all). *

* Note: since it is assumed that the start location must either have * been collected by now, or is not accessible (i.e. implementation * [always] returns null), no exception is allowed to be throws, as * no parsing should ever need to be done (unlike with * {@link #getEndLocation}). * * @return Location of the first character of the current event in * the input source (which will also be the starting location * of the following event, if any, or EOF if not), or null (if * implementation does not track locations). */ public XMLStreamLocation2 getStartLocation(); /** * A method that returns the current location of the stream reader * at the input source. This is somewhere between the start * and end locations (inclusive), depending on how parser does it * parsing (for non-lazy implementations it's always the end location; * for others something else). *

* Since this location information should always be accessible, no * further parsing is to be done, and no exceptions can be thrown. * * @return Location of the next character reader will parse in the * input source. */ public XMLStreamLocation2 getCurrentLocation(); /** * An optional method that either returns the location object that points the * ending position of the current event, or null if implementation * does not keep track of it (some may return only start location; and * some no location at all). *

* Note: since some implementations may not yet know the end location * (esp. ones that do lazy loading), this call may require further * parsing. As a result, this method may throw a parsing or I/O * errors. * * @return Location right after the end * of the current event (which will also be the start location of * the next event, if any, or of EOF otherwise). * * @throws XMLStreamException If the stream reader had to advance to * the end of the event (to find the location), it may encounter a * parsing (or I/O) error; if so, that gets thrown */ public XMLStreamLocation2 getEndLocation() throws XMLStreamException; }





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