3 import java.util.ArrayList;
4 import java.util.Iterator;
6 import java.util.NoSuchElementException;
7 import org.yaz4j.exception.ZoomException;
8 import org.yaz4j.jni.SWIGTYPE_p_ZOOM_record_p;
9 import org.yaz4j.jni.SWIGTYPE_p_ZOOM_resultset_p;
10 import org.yaz4j.jni.SWIGTYPE_p_p_ZOOM_record_p;
11 import org.yaz4j.jni.yaz4jlib;
14 * This class represents a "buffered handle" to the result set created on the
15 * server and thus retrieving records may involve a request to the server if
16 * those records are not locally cached. Details on how to configure the retrieval
17 * (present) process are available in the YAZ manual
19 * @see <a href="http://www.indexdata.com/yaz/doc/zoom.resultsets.html">YAZ ZOOM result sets</a>
21 * Because of server misbehavior or errors during retrieval the
22 * "getRecord" method may either return null or throw exceptions, even when the
23 * index of retrieved records lies within the bounds of the set. Client
24 * code should be prepared for such situations.
26 * This class implements the iterable interface and as such can be used within
27 * foreach loops, it's important to note, however, that in this case the errors
28 * during retrieval will be masked with standard NoSuchElementExceptions.
32 public class ResultSet implements Iterable<Record> {
35 private Connection conn;
36 private SWIGTYPE_p_ZOOM_resultset_p resultSet;
37 private long size = 0;
38 private boolean disposed = false;
40 ResultSet(SWIGTYPE_p_ZOOM_resultset_p resultSet, Connection conn) {
41 this.resultSet = resultSet;
42 size = yaz4jlib.ZOOM_resultset_size(this.resultSet);
47 public void finalize() {
52 * Read option by name.
53 * @param name option name
54 * @return option value
56 public String option(String name) {
57 return yaz4jlib.ZOOM_resultset_option_get(resultSet, name);
61 * Write option with a given name.
62 * @param name option name
63 * @param value option value
64 * @return result set (self) for chainability
66 public ResultSet option(String name, String value) {
67 yaz4jlib.ZOOM_resultset_option_set(resultSet, name, value);
71 public Record getRecord(long index) throws ZoomException {
72 SWIGTYPE_p_ZOOM_record_p record =
73 yaz4jlib.ZOOM_resultset_record(resultSet, index);
74 //may be out of range or unsupported syntax
78 int errorCode = yaz4jlib.ZOOM_record_error(record, null, null, null);
80 throw new ZoomException("Record excpetion, code " + errorCode);
82 return new Record(record, this);
86 * Retrieve a collection of records at once. If a record cannot be retrieved,
87 * it is omitted from the list (thus the list size may be smaller than 'count').
88 * @param start start index within the result set
89 * @param count number of records to retrieve
91 * @throws ZoomException raised in case of protocol errors
93 public List<Record> getRecords(long start, int count) throws ZoomException {
94 List<Record> out = new ArrayList<Record>(count);
95 SWIGTYPE_p_p_ZOOM_record_p recs = yaz4jlib.new_zoomRecordArray(count);
96 yaz4jlib.ZOOM_resultset_records(resultSet, recs, start, count);
97 for (int i = 0; i < count; i++) {
98 SWIGTYPE_p_ZOOM_record_p record =
99 yaz4jlib.zoomRecordArray_getitem(recs, i);
100 if (record == null) {
103 int errorCode = yaz4jlib.ZOOM_record_error(record, null, null, null);
104 if (errorCode != 0) {
105 throw new ZoomException("Record excpetion, code " + errorCode);
107 out.add(new Record(record, this));
113 public Iterator<Record> iterator() {
114 return new Iterator<Record>() {
117 public boolean hasNext() {
122 public Record next() {
124 return getRecord(cur++);
125 } catch (ZoomException ze) {
126 throw new NoSuchElementException(ze.getMessage());
131 public void remove() {
132 throw new UnsupportedOperationException("remove operation not supported");
137 public ResultSet sort(String type, String spec) throws ZoomException {
138 int ret = yaz4jlib.ZOOM_resultset_sort1(resultSet, type, spec);
139 if (ret != 0) throw new ZoomException("Sorting resultset failed");
143 public long getHitCount() {
149 yaz4jlib.ZOOM_resultset_destroy(resultSet);