feat: ambiguous column name

modules/iceaxe-core/src/main/java/com/tsurugidb/iceaxe/result/package-info.java

@@ -0,0 +1,4 @@
+/**
+ * Iceaxe result classes.
+ */
+package com.tsurugidb.iceaxe.result;

modules/iceaxe-core/src/main/java/com/tsurugidb/iceaxe/sql/result/IceaxeResultNameList.java

@@ -0,0 +1,191 @@
+package com.tsurugidb.iceaxe.sql.result;
+
+import java.text.MessageFormat;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+import com.tsurugidb.iceaxe.util.IceaxeInternal;
+import com.tsurugidb.sql.proto.SqlCommon.Column;
+
+/**
+ * name utility.
+ *
+ * @since 1.5.0
+ */
+@IceaxeInternal
+@ThreadSafe
+public class IceaxeResultNameList {
+
+    /**
+     * ambiguous name policy.
+     *
+     * @since 1.5.0
+     */
+    public enum IceaxeAmbiguousNamePolicy {
+        /** error. */
+        ERROR,
+        /** get first column. */
+        FIRST,
+        /** get last column. */
+        LAST,
+    }
+
+    /**
+     * create name utility.
+     *
+     * @param lowColumnList low column list
+     * @return name utility
+     */
+    public static IceaxeResultNameList of(List<? extends Column> lowColumnList) {
+        var nameList = toNameList(lowColumnList);
+        return new IceaxeResultNameList(nameList);
+    }
+
+    /**
+     * convert to name list.
+     *
+     * @param lowColumnList low column list
+     * @return name list
+     */
+    public static List<String> toNameList(List<? extends Column> lowColumnList) {
+        var nameList = new ArrayList<String>(lowColumnList.size());
+        int i = 0;
+        for (var lowColumn : lowColumnList) {
+            var name = getColumnName(lowColumn, i++);
+            nameList.add(name);
+        }
+        return nameList;
+    }
+
+    private static String getColumnName(Column lowColumn, int index) {
+        var lowName = lowColumn.getName();
+        if (lowName == null || lowName.isEmpty()) {
+            return "@#" + index;
+        }
+        return lowName;
+    }
+
+    private final List<String> nameList;
+
+    private Map<String, List<Integer>> nameIndexMap = null;
+
+    /**
+     * Creates a new instance.
+     *
+     * @param nameList name list
+     */
+    public IceaxeResultNameList(List<String> nameList) {
+        this.nameList = List.copyOf(nameList);
+    }
+
+    /**
+     * get name list.
+     *
+     * @return name list
+     */
+    public List<String> getNameList() {
+        return this.nameList;
+    }
+
+    /**
+     * get size.
+     *
+     * @return size of name list
+     */
+    public int size() {
+        return nameList.size();
+    }
+
+    /**
+     * get name.
+     *
+     * @param index column index
+     * @return column name
+     */
+    public String getName(int index) {
+        return nameList.get(index);
+    }
+
+    /**
+     * get index.
+     *
+     * @param name   column name
+     * @param policy ambiguous name policy
+     * @return column index
+     */
+    public int getIndex(String name, IceaxeAmbiguousNamePolicy policy) {
+        var indexMap = getNameIndexMap();
+        List<Integer> indexList = indexMap.get(name);
+        if (indexList == null) {
+            throw new IllegalArgumentException(MessageFormat.format("not found column. name={0}", name));
+        }
+
+        if (indexList.size() == 1) {
+            return indexList.get(0);
+        }
+
+        switch (policy) {
+        case ERROR:
+            throw new IllegalArgumentException(MessageFormat.format("column is ambiguous. name={0}", name));
+        case FIRST:
+            return indexList.get(0); // getHead()
+        case LAST:
+            return indexList.get(indexList.size() - 1); // getLast()
+        default:
+            throw new UnsupportedOperationException(MessageFormat.format("unsupported policy. policy={0}", policy));
+        }
+    }
+
+    /**
+     * get index.
+     *
+     * @param name     column name
+     * @param subIndex index for same name
+     * @return column index
+     */
+    public int getIndex(String name, int subIndex) {
+        var indexMap = getNameIndexMap();
+        List<Integer> indexList = indexMap.get(name);
+        if (indexList == null) {
+            throw new IllegalArgumentException(MessageFormat.format("not found column. name={0}", name));
+        }
+
+        if (0 <= subIndex && subIndex < indexList.size()) {
+            return indexList.get(subIndex);
+        }
+
+        throw new IllegalArgumentException(MessageFormat.format("not found column. name={0}, subIndex={1}", name, subIndex));
+    }
+
+    /**
+     * get name-index map.
+     *
+     * @return name-index map
+     */
+    protected Map<String, List<Integer>> getNameIndexMap() {
+        if (this.nameIndexMap == null) {
+            var map = new HashMap<String, List<Integer>>(nameList.size());
+            for (int i = 0; i < nameList.size(); i++) {
+                String name = nameList.get(i);
+                List<Integer> indexList = map.computeIfAbsent(name, k -> new ArrayList<>(2));
+                indexList.add(i);
+            }
+            this.nameIndexMap = map;
+        }
+        return this.nameIndexMap;
+    }
+
+    @Override
+    public String toString() {
+        var map = this.nameIndexMap;
+        if (map != null) {
+            return getClass().getSimpleName() + map;
+        }
+
+        return getClass().getSimpleName() + nameList;
+    }
+}

modules/iceaxe-core/src/main/java/com/tsurugidb/iceaxe/sql/result/TsurugiQueryResult.java

@@ -359,25 +359,14 @@ public int getReadCount() {
      */
     public List<String> getNameList() throws IOException, InterruptedException, TsurugiTransactionException {
         try {
-            return getNameList(this, getLowResultSet());
+            var lowColumnList = getLowColumnList(this, getLowResultSet());
+            return IceaxeResultNameList.toNameList(lowColumnList);
         } catch (Throwable e) {
             event(e, listener -> listener.readException(this, e));
             throw e;
         }
     }
 
-    static List<String> getNameList(TsurugiQueryResult<?> rs, ResultSet lowResultSet) throws IOException, InterruptedException, TsurugiTransactionException {
-        var lowColumnList = getLowColumnList(rs, lowResultSet);
-        var size = lowColumnList.size();
-        var list = new ArrayList<String>(size);
-        int i = 0;
-        for (var lowColumn : lowColumnList) {
-            var name = getColumnName(lowColumn, i++);
-            list.add(name);
-        }
-        return list;
-    }
-
     static List<? extends Column> getLowColumnList(TsurugiQueryResult<?> rs, ResultSet lowResultSet) throws IOException, InterruptedException, TsurugiTransactionException {
         try {
             var lowMetadata = lowResultSet.getMetadata();
@@ -387,14 +376,6 @@ static List<? extends Column> getLowColumnList(TsurugiQueryResult<?> rs, ResultS
         }
     }
 
-    static String getColumnName(Column lowColumn, int index) {
-        var lowName = lowColumn.getName();
-        if (lowName == null || lowName.isEmpty()) {
-            return "@#" + index;
-        }
-        return lowName;
-    }
-
     // read
 
     /**