X-Git-Url: http://git.indexdata.com/?a=blobdiff_plain;f=src%2Fmain%2Fjava%2Forg%2Fyaz4j%2FResultSet.java;h=b2fd11958beb65d303f0ceef91cf1afcf7cfa3e3;hb=8c7413fbaf0870975229e8e101f79096b5dfe6f0;hp=ab3af1a04498e69d3c2250169c397c70d2e3fa37;hpb=04a60ffa2d97a96191fcad999557818c7c95a5f9;p=yaz4j-moved-to-github.git

diff --git a/src/main/java/org/yaz4j/ResultSet.java b/src/main/java/org/yaz4j/ResultSet.java
index ab3af1a..b2fd119 100644
--- a/src/main/java/org/yaz4j/ResultSet.java
+++ b/src/main/java/org/yaz4j/ResultSet.java
@@ -1,11 +1,35 @@
 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 {
+/**
+ * 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
 
   private Connection conn;
@@ -44,7 +68,7 @@ public class ResultSet {
     return this;
   }
 
-  public Record getRecord(int index) throws ZoomException {
+  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
@@ -57,6 +81,75 @@ public class ResultSet {
     }
     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;
+  }
+
+  @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;