diff options
| author | Benjamin Culkin <scorpress@gmail.com> | 2024-05-27 11:38:33 -0400 |
|---|---|---|
| committer | Benjamin Culkin <scorpress@gmail.com> | 2024-05-27 11:38:33 -0400 |
| commit | 7c279747beb43c7e88633a6228a155a30e6834f7 (patch) | |
| tree | 511176048944fa7332dc1a163a6148c46e7c61b3 /israfil-foundation-collections/src/main/java/net/israfil/foundation/collections/IterableResultSet.java | |
Initial import
Diffstat (limited to 'israfil-foundation-collections/src/main/java/net/israfil/foundation/collections/IterableResultSet.java')
| -rw-r--r-- | israfil-foundation-collections/src/main/java/net/israfil/foundation/collections/IterableResultSet.java | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/israfil-foundation-collections/src/main/java/net/israfil/foundation/collections/IterableResultSet.java b/israfil-foundation-collections/src/main/java/net/israfil/foundation/collections/IterableResultSet.java new file mode 100644 index 0000000..9258c6f --- /dev/null +++ b/israfil-foundation-collections/src/main/java/net/israfil/foundation/collections/IterableResultSet.java @@ -0,0 +1,132 @@ +/*
+ * Copyright (c) 2006 Israfil Consulting Services Corporation
+ * Copyright (c) 2006 Christian Edward Gruber
+ * All Rights Reserved
+ *
+ * This software is licensed under the Berkeley Standard Distribution license,
+ * (BSD license), as defined below:
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * 3. Neither the name of Israfil Consulting Services nor the names of its contributors
+ * may be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
+ * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * $Id: IterableResultSet.java 26 2006-02-13 16:35:44Z cgruber $
+ */
+package net.israfil.foundation.collections;
+
+import java.lang.ref.WeakReference;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.WeakHashMap;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * A simple wrapper that provides an Iterable implementation back-ended
+ * by a result-set. Allows a ResultSet to be used in a JDK 5.0 extended
+ * for-loop syntax.
+ *
+ * No result set can have more than one Iterable wrapper around it at a time.
+ * However, it is impossible for this object to know implicitly when it is
+ * no longer required (to free the reference). Therefore, when this
+ * wrapper is concluded, it should be disposed of via the dispose() method.
+ *
+ * @author <a href="mailto:cgruber@israfil.net">Christian Edward Gruber </a>
+ */
+public class IterableResultSet implements Iterable<Map<String,Object>> {
+
+ protected static final Map<ResultSet,IterableResultSet> iterables = new WeakHashMap<ResultSet,IterableResultSet>();
+ protected final WeakReference<ResultSet> resultRef;
+
+ public IterableResultSet(ResultSet result) {
+ if (iterables.containsKey(result)) throw new RuntimeException("Cannot have two IterableResultSet wrappers around the same resultset.");
+ this.resultRef = new WeakReference<ResultSet>(result);
+ }
+
+ public Iterator<Map<String,Object>> iterator() {
+ if (resultRef.get() == null) throw new RuntimeException("ResultSet object not available to iterate.");
+ return new ResultSetIterator(resultRef.get());
+ }
+
+ public void dispose() {
+ ResultSet rs = resultRef.get();
+ if (rs == null) return;
+ if (iterables.containsKey(rs)) {
+ iterables.get(rs).dispose();
+ }
+ resultRef.clear();
+ }
+
+ public static class ResultSetIterator implements Iterator<Map<String,Object>> {
+ private static final Logger logger = Logger.getLogger(ResultSetIterator.class.getName());
+ protected ResultSet result;
+
+ boolean hasNext = true;
+
+
+ public ResultSetIterator(ResultSet result) {
+ this.result = result;
+ try {
+ hasNext = result.first();
+ } catch (SQLException e) {
+ throw new RuntimeException(e);
+ }
+ }
+
+ public boolean hasNext() {
+ return hasNext;
+ }
+
+ public Map<String,Object> next() {
+ try {
+ Map<String,Object> row = new HashMap<String,Object>();
+ for(int i = 1; i <= result.getMetaData().getColumnCount(); i++) {
+ row.put(result.getMetaData().getColumnName(i),result.getObject(i));
+ }
+ hasNext = result.next();
+ return row;
+ } catch (SQLException e) {
+ logger.log(Level.FINER,"SQLException thrown while iterating across result set.",e);
+ return null;
+ }
+ }
+
+ public void remove() {
+ throw new UnsupportedOperationException("Removal of records from underlying result set not supported.");
+ }
+
+ public void dispose() {
+ if (iterables.containsKey(result)) iterables.remove(result);
+ result = null;
+ }
+
+ public void finalize() throws Throwable {
+ dispose();
+ super.finalize();
+ }
+ }
+}
+
+
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