package org.yaz4j;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.NoSuchElementException;
+import org.yaz4j.exception.ZoomException;
import org.yaz4j.jni.SWIGTYPE_p_ZOOM_record_p;
import org.yaz4j.jni.SWIGTYPE_p_ZOOM_resultset_p;
+import org.yaz4j.jni.SWIGTYPE_p_p_ZOOM_record_p;
import org.yaz4j.jni.yaz4jlib;
-public class ResultSet {
- //for GC refcount
- private Connection conn;
- private SWIGTYPE_p_ZOOM_resultset_p resultSet;
- private long size = 0;
- private boolean disposed = false;
-
- ResultSet(SWIGTYPE_p_ZOOM_resultset_p resultSet, Connection conn) {
- this.resultSet = resultSet;
- size = yaz4jlib.ZOOM_resultset_size(this.resultSet);
- this.conn = conn;
- }
+/**
+ * This class represents a "buffered handle" to the result set created on the
+ * server and thus retrieving records may involve a request to the server if
+ * those records are not locally cached. Details on how to configure the retrieval
+ * (present) process are available in the YAZ manual
+ *
+ * @see <a href="http://www.indexdata.com/yaz/doc/zoom.resultsets.html">YAZ ZOOM result sets</a>
+ *
+ * Because of server misbehavior or errors during retrieval the
+ * "getRecord" method may either return null or throw exceptions, even when the
+ * index of retrieved records lies within the bounds of the set. Client
+ * code should be prepared for such situations.
+ *
+ * This class implements the iterable interface and as such can be used within
+ * foreach loops, it's important to note, however, that in this case the errors
+ * during retrieval will be masked with standard NoSuchElementExceptions.
+ *
+ * @author jakub
+ */
+public class ResultSet implements Iterable<Record> {
+ //for GC refcount
- @Override
- public void finalize() {
- this._dispose();
- }
+ private Connection conn;
+ private SWIGTYPE_p_ZOOM_resultset_p resultSet;
+ private long size = 0;
+ private boolean disposed = false;
- /**
- * Read option by name.
- * @param name option name
- * @return option value
- */
- public String option(String name) {
- return yaz4jlib.ZOOM_resultset_option_get(resultSet, name);
- }
+ ResultSet(SWIGTYPE_p_ZOOM_resultset_p resultSet, Connection conn) {
+ this.resultSet = resultSet;
+ size = yaz4jlib.ZOOM_resultset_size(this.resultSet);
+ this.conn = conn;
+ }
- /**
- * Write option with a given name.
- * @param name option name
- * @param value option value
- * @return result set (self) for chainability
- */
- public ResultSet option(String name, String value) {
- yaz4jlib.ZOOM_resultset_option_set(resultSet, name, value);
- return this;
- }
+ @Override
+ public void finalize() {
+ this._dispose();
+ }
- public Record getRecord(int index) {
- SWIGTYPE_p_ZOOM_record_p record =
- yaz4jlib.ZOOM_resultset_record(resultSet, index);
- return new Record(record, this);
- }
+ /**
+ * Read option by name.
+ * @param name option name
+ * @return option value
+ */
+ public String option(String name) {
+ return yaz4jlib.ZOOM_resultset_option_get(resultSet, name);
+ }
+
+ /**
+ * Write option with a given name.
+ * @param name option name
+ * @param value option value
+ * @return result set (self) for chainability
+ */
+ public ResultSet option(String name, String value) {
+ yaz4jlib.ZOOM_resultset_option_set(resultSet, name, value);
+ return this;
+ }
- public long getSize() {
- return size;
+ public Record getRecord(long index) throws ZoomException {
+ SWIGTYPE_p_ZOOM_record_p record =
+ yaz4jlib.ZOOM_resultset_record(resultSet, index);
+ //may be out of range or unsupported syntax
+ if (record == null) {
+ return null;
+ }
+ int errorCode = yaz4jlib.ZOOM_record_error(record, null, null, null);
+ if (errorCode != 0) {
+ throw new ZoomException("Record excpetion, code " + errorCode);
}
+ return new Record(record, this);
+ }
+
+ /**
+ * Retrieve a collection of records at once. If a record cannot be retrieved,
+ * it is omitted from the list (thus the list size may be smaller than 'count').
+ * @param start start index within the result set
+ * @param count number of records to retrieve
+ * @return
+ * @throws ZoomException raised in case of protocol errors
+ */
+ public List<Record> getRecords(long start, int count) throws ZoomException {
+ List<Record> out = new ArrayList<Record>(count);
+ SWIGTYPE_p_p_ZOOM_record_p recs = yaz4jlib.new_zoomRecordArray(count);
+ yaz4jlib.ZOOM_resultset_records(resultSet, recs, start, count);
+ ZoomException err = this.conn.getZoomException();
+ if (err != null) {
+ throw err;
+ }
+ for (int i = 0; i < count; i++) {
+ SWIGTYPE_p_ZOOM_record_p record =
+ yaz4jlib.zoomRecordArray_getitem(recs, i);
+ if (record == null) {
+ continue;
+ }
+ int errorCode = yaz4jlib.ZOOM_record_error(record, null, null, null);
+ if (errorCode != 0) {
+ throw new ZoomException("Record excpetion, code " + errorCode);
+ }
+ out.add(new Record(record, this));
+ }
+ return out;
+ }
- void _dispose() {
- if (!disposed) {
- yaz4jlib.ZOOM_resultset_destroy(resultSet);
- resultSet = null;
- conn = null;
- disposed = true;
+ @Override
+ public Iterator<Record> iterator() {
+ return new Iterator<Record>() {
+ private long cur;
+ @Override
+ public boolean hasNext() {
+ return cur < size;
+ }
+
+ @Override
+ public Record next() {
+ try {
+ return getRecord(cur++);
+ } catch (ZoomException ze) {
+ throw new NoSuchElementException(ze.getMessage());
}
+ }
+
+ @Override
+ public void remove() {
+ throw new UnsupportedOperationException("remove operation not supported");
+ }
+ };
+ }
+
+ /**
+ *
+ * @param type
+ * @param spec
+ * @return
+ * @throws ZoomException
+ */
+ public ResultSet sort(String type, String spec) throws ZoomException {
+ int ret = yaz4jlib.ZOOM_resultset_sort1(resultSet, type, spec);
+ if (ret != 0) throw new ZoomException("Sorting resultset failed");
+ return this;
+ }
+
+ public long getHitCount() {
+ return size;
+ }
+
+ void _dispose() {
+ if (!disposed) {
+ yaz4jlib.ZOOM_resultset_destroy(resultSet);
+ resultSet = null;
+ conn = null;
+ disposed = true;
}
+ }
}
projects / yaz4j-moved-to-github.git / blobdiff