| 1 | package org.springframework.batch.item.xml.stax; |
| 2 | |
| 3 | import java.util.ArrayList; |
| 4 | import java.util.List; |
| 5 | |
| 6 | import javax.xml.stream.events.XMLEvent; |
| 7 | |
| 8 | /** |
| 9 | * Holds a list of XML events, typically corresponding to a single record. |
| 10 | * |
| 11 | * @author tomas.slanina |
| 12 | */ |
| 13 | class EventSequence { |
| 14 | |
| 15 | private static final int BEFORE_BEGINNING = -1; |
| 16 | |
| 17 | private List events; |
| 18 | |
| 19 | private int currentIndex; |
| 20 | |
| 21 | /** |
| 22 | * Creates instance of this class. |
| 23 | * |
| 24 | */ |
| 25 | public EventSequence() { |
| 26 | init(); |
| 27 | } |
| 28 | |
| 29 | /** |
| 30 | * Adds event to the list of stored events. |
| 31 | * |
| 32 | * @param event |
| 33 | */ |
| 34 | public void addEvent(XMLEvent event) { |
| 35 | events.add(event); |
| 36 | } |
| 37 | |
| 38 | /** |
| 39 | * Gets next XMLEvent from cache and moves cursor to next event. |
| 40 | * If cache contains no more events, null is returned. |
| 41 | */ |
| 42 | public XMLEvent nextEvent() { |
| 43 | return (hasNext()) ? (XMLEvent)events.get(++currentIndex) :null; |
| 44 | } |
| 45 | |
| 46 | /** |
| 47 | * Gets next XMLEvent from cache but cursor remains on the same position. |
| 48 | * If cache contains no more events, null is returned. |
| 49 | */ |
| 50 | public XMLEvent peek() { |
| 51 | return (hasNext()) ? (XMLEvent)events.get(currentIndex+1) :null; |
| 52 | } |
| 53 | |
| 54 | /** |
| 55 | * Removes events from the internal cache. |
| 56 | * |
| 57 | */ |
| 58 | public void clear() { |
| 59 | init(); |
| 60 | } |
| 61 | |
| 62 | /** |
| 63 | * Resets cursor to the cache start. |
| 64 | * |
| 65 | */ |
| 66 | public void reset() { |
| 67 | currentIndex = BEFORE_BEGINNING; |
| 68 | } |
| 69 | |
| 70 | /** |
| 71 | * Check if there are more events. Returns true if there are more events and |
| 72 | * false otherwise. |
| 73 | * |
| 74 | * @return true if the event reader has more events, false otherwise |
| 75 | */ |
| 76 | public boolean hasNext() { |
| 77 | return currentIndex + 1 < events.size(); |
| 78 | } |
| 79 | |
| 80 | private void init() { |
| 81 | events = (events != null) ? new ArrayList(events.size()) |
| 82 | : new ArrayList(1000); |
| 83 | |
| 84 | reset(); |
| 85 | } |
| 86 | |
| 87 | |
| 88 | } |