Fix line retainAll doesn't modify names and values array

src/main/java/com/baidu/hugegraph/loader/builder/ElementBuilder.java

@@ -104,7 +104,7 @@ public boolean hasNext() {
     @Override
     public Record<GE> next() {
         Line line = this.reader.next();
-        Map<String, Object> keyValues = line.toMap();
+        Map<String, Object> keyValues = line.keyValues();
         try {
             keyValues = this.filterFields(keyValues);
             GE element = this.build(keyValues);

src/main/java/com/baidu/hugegraph/loader/reader/Line.java

@@ -22,72 +22,73 @@
 import java.util.Arrays;
 import java.util.Map;
 
+import com.baidu.hugegraph.util.E;
 import com.baidu.hugegraph.util.InsertionOrderUtil;
 
 public final class Line {
 
     private final String rawLine;
     private String[] names;
     private Object[] values;
-    private Map<String, Object> keyValues;
+    private final Map<String, Object> keyValues;
 
     public Line(String rawLine, Map<String, Object> keyValues) {
+        E.checkArgumentNotNull(rawLine, "The rawLine can't be null");
+        E.checkArgumentNotNull(keyValues, "The keyValues can't be null");
         this.rawLine = rawLine;
-        this.names = null;
-        this.values = null;
         this.keyValues = keyValues;
+        this.names = getNames(keyValues);
+        this.values = getValues(keyValues, this.names);
     }
 
     public Line(String rawLine, String[] names, Object[] values) {
-        assert names.length == values.length;
+        E.checkArgumentNotNull(rawLine, "The rawLine can't be null");
+        E.checkArgumentNotNull(names, "The names can't be null");
+        E.checkArgumentNotNull(values, "The values can't be null");
+        E.checkArgument(names.length == values.length,
+                        "The length of names %s should be same as values %s");
         this.rawLine = rawLine;
         this.names = names;
         this.values = values;
-        this.keyValues = null;
+        this.keyValues = InsertionOrderUtil.newMap();
+        for (int i = 0; i < this.names.length; i++) {
+            this.keyValues.put(this.names[i], this.values[i]);
+        }
     }
 
     public String rawLine() {
         return this.rawLine;
     }
 
     public final String[] names() {
-        if (this.names != null) {
-            return this.names;
-        } else {
-            assert this.keyValues != null;
-            return this.keyValues.keySet().toArray(new String[]{});
-        }
+        return this.names;
     }
 
     public final Object[] values() {
-        if (this.values != null) {
-            return this.values;
-        } else {
-            assert this.keyValues != null;
-            String[] names = this.names();
-            Object[] values = new Object[names.length];
-            for (int i = 0; i < names.length; i++) {
-                values[i] = this.keyValues.get(names[i]);
-            }
-            return values;
-        }
+        return this.values;
     }
 
-    public Map<String, Object> toMap() {
-        if (this.keyValues != null) {
-            return this.keyValues;
-        }
-        String[] names = this.names();
-        Object[] values = this.values();
-        this.keyValues = InsertionOrderUtil.newMap();
-        for (int i = 0, n = names.length; i < n; i++) {
-            this.keyValues.put(names[i], values[i]);
-        }
+    public Map<String, Object> keyValues() {
         return this.keyValues;
     }
 
     public void retainAll(String[] names) {
-        this.toMap().keySet().retainAll(Arrays.asList(names));
+        this.keyValues.keySet().retainAll(Arrays.asList(names));
+        this.names = getNames(keyValues);
+        this.values = getValues(keyValues, this.names);
+    }
+
+    private static String[] getNames(Map<String, Object> keyValues) {
+        return keyValues.keySet().toArray(new String[]{});
+    }
+
+    private static Object[] getValues(Map<String, Object> keyValues,
+                                      String[] names) {
+        Object[] values = new Object[names.length];
+        for (int i = 0; i < names.length; i++) {
+            values[i] = keyValues.get(names[i]);
+        }
+        return values;
     }
 
     @Override

src/main/java/com/baidu/hugegraph/loader/reader/jdbc/RowFetcher.java

@@ -121,6 +121,8 @@ public List<Line> nextBatch() throws SQLException {
 
         String select = this.source.vendor().buildSelectSql(this.source,
                                                             this.nextStartRow);
+        LOG.debug("The sql for select is: {}", select);
+
         List<Line> batch = new ArrayList<>(this.source.batchSize() + 1);
         try (Statement stmt = this.conn.createStatement();
              ResultSet result = stmt.executeQuery(select)) {

src/test/java/com/baidu/hugegraph/loader/test/unit/LineTest.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2017 HugeGraph Authors
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with this
+ * work for additional information regarding copyright ownership. The ASF
+ * licenses this file to You under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+package com.baidu.hugegraph.loader.test.unit;
+
+import org.junit.Test;
+
+import com.baidu.hugegraph.loader.reader.Line;
+import com.baidu.hugegraph.testutil.Assert;
+import com.google.common.collect.ImmutableMap;
+
+public class LineTest {
+
+    @Test
+    public void testInvalidParam() {
+        Assert.assertThrows(IllegalArgumentException.class, () -> {
+            new Line(null, ImmutableMap.of("id", 1, "name", "marko"));
+        });
+        Assert.assertThrows(IllegalArgumentException.class, () -> {
+            new Line("1,marko", null);
+        });
+
+        Assert.assertThrows(IllegalArgumentException.class, () -> {
+            new Line(null, new String[]{"id", "name"},
+                     new Object[]{1, "marko"});
+        });
+        Assert.assertThrows(IllegalArgumentException.class, () -> {
+            new Line("1,marko", null, new Object[]{1, "marko"});
+        });
+        Assert.assertThrows(IllegalArgumentException.class, () -> {
+            new Line("1,marko", new String[]{"id", "name"}, null);
+        });
+    }
+
+    @Test
+    public void testKeyValues() {
+        Line line = new Line("1,marko,27",
+                             new String[]{"id", "name", "age"},
+                             new Object[]{1, "marko", 27});
+        Assert.assertEquals(ImmutableMap.of("id", 1, "name", "marko", "age", 27),
+                            line.keyValues());
+    }
+
+    @Test
+    public void testRetainAll() {
+        Line line = new Line("1,marko,27",
+                             new String[]{"id", "name", "age"},
+                             new Object[]{1, "marko", 27});
+        line.retainAll(new String[]{"id"});
+        Assert.assertArrayEquals(new String[]{"id"}, line.names());
+        Assert.assertArrayEquals(new Object[]{1}, line.values());
+    }
+}

src/test/java/com/baidu/hugegraph/loader/test/unit/UnitTestSuite.java

@@ -24,6 +24,7 @@
 
 @RunWith(Suite.class)
 @Suite.SuiteClasses({
+    LineTest.class,
     LoadProgressTest.class
 })
 public class UnitTestSuite {