[CALCITE-4199] Add nullability annotations

Author: vlsi

core/src/main/java/org/apache/calcite/DataContext.java

@@ -25,6 +25,8 @@
 
 import com.google.common.base.CaseFormat;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.lang.reflect.Modifier;
@@ -42,17 +44,17 @@ public interface DataContext {
   /**
    * Returns a sub-schema with a given name, or null.
    */
-  SchemaPlus getRootSchema();
+  @Nullable SchemaPlus getRootSchema();
 
   /**
    * Returns the type factory.
    */
-  JavaTypeFactory getTypeFactory();
+  @Nullable JavaTypeFactory getTypeFactory();
 
   /**
    * Returns the query provider.
    */
-  QueryProvider getQueryProvider();
+  @Nullable QueryProvider getQueryProvider();
 
   /**
    * Returns a context variable.
@@ -62,7 +64,7 @@ public interface DataContext {
    *
    * @param name Name of variable
    */
-  Object get(String name);
+  @Nullable Object get(String name);
 
   /** Variable that may be asked for in a call to {@link DataContext#get}. */
   enum Variable {

core/src/main/java/org/apache/calcite/adapter/clone/ArrayTable.java

@@ -41,6 +41,8 @@
 import com.google.common.base.Supplier;
 import com.google.common.collect.ImmutableList;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 import java.lang.reflect.Array;
 import java.lang.reflect.Type;
 import java.util.AbstractList;
@@ -82,9 +84,9 @@ class ArrayTable extends AbstractQueryableTable implements ScannableTable {
     return Statistics.of(content.size, keys, content.collations);
   }
 
-  @Override public Enumerable<Object[]> scan(DataContext root) {
-    return new AbstractEnumerable<Object[]>() {
-      @Override public Enumerator<Object[]> enumerator() {
+  @Override public Enumerable<@Nullable Object[]> scan(DataContext root) {
+    return new AbstractEnumerable<@Nullable Object[]>() {
+      @Override public Enumerator<@Nullable Object[]> enumerator() {
         final Content content = supplier.get();
         return content.arrayEnumerator();
       }
@@ -225,7 +227,7 @@ public static List asList(final Representation representation,
       // Cache size. It might be expensive to compute.
       final int size = representation.size(dataSet);
       return new AbstractList() {
-        @Override public Object get(int index) {
+        @Override public @Nullable Object get(int index) {
           return representation.getObject(dataSet, index);
         }
 
@@ -243,9 +245,9 @@ public interface Representation {
 
     /** Converts a value set into a compact representation. If
      * {@code sources} is not null, permutes. */
-    Object freeze(ColumnLoader.ValueSet valueSet, int[] sources);
+    Object freeze(ColumnLoader.ValueSet valueSet, int @Nullable [] sources);
 
-    Object getObject(Object dataSet, int ordinal);
+    @Nullable Object getObject(Object dataSet, int ordinal);
     int getInt(Object dataSet, int ordinal);
 
     /** Creates a data set that is the same as a given data set
@@ -277,7 +279,7 @@ public static class ObjectArray implements Representation {
       return RepresentationType.OBJECT_ARRAY;
     }
 
-    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int[] sources) {
+    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int @Nullable [] sources) {
       // We assume the values have been canonized.
       final List<Comparable> list = permuteList(valueSet.values, sources);
       return list.toArray(new Comparable[0]);
@@ -334,7 +336,7 @@ public static class PrimitiveArray implements Representation {
       return RepresentationType.PRIMITIVE_ARRAY;
     }
 
-    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int[] sources) {
+    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int @Nullable [] sources) {
       //noinspection unchecked
       return primitive.toArray2(
           permuteList((List) valueSet.values, sources));
@@ -344,7 +346,7 @@ public static class PrimitiveArray implements Representation {
       return primitive.permute(dataSet, sources);
     }
 
-    @Override public Object getObject(Object dataSet, int ordinal) {
+    @Override public @Nullable Object getObject(Object dataSet, int ordinal) {
       return p.arrayItem(dataSet, ordinal);
     }
 
@@ -375,7 +377,7 @@ public static class PrimitiveDictionary implements Representation {
       return RepresentationType.PRIMITIVE_DICTIONARY;
     }
 
-    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int[] sources) {
+    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int @Nullable [] sources) {
       throw new UnsupportedOperationException(); // TODO:
     }
 
@@ -423,7 +425,7 @@ public static class ObjectDictionary implements Representation {
       return RepresentationType.OBJECT_DICTIONARY;
     }
 
-    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int[] sources) {
+    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int @Nullable [] sources) {
       final int n = valueSet.map.keySet().size();
       int extra = valueSet.containsNull ? 1 : 0;
       Comparable[] codeValues =
@@ -486,7 +488,7 @@ public static class StringDictionary implements Representation {
       return RepresentationType.STRING_DICTIONARY;
     }
 
-    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int[] sources) {
+    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int @Nullable [] sources) {
       throw new UnsupportedOperationException(); // TODO:
     }
 
@@ -524,7 +526,7 @@ public static class ByteStringDictionary implements Representation {
       return RepresentationType.BYTE_STRING_DICTIONARY;
     }
 
-    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int[] sources) {
+    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int @Nullable [] sources) {
       throw new UnsupportedOperationException(); // TODO:
     }
 
@@ -565,7 +567,7 @@ public static class Constant implements Representation {
       return RepresentationType.CONSTANT;
     }
 
-    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int[] sources) {
+    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int @Nullable [] sources) {
       final int size = valueSet.values.size();
       return Pair.of(size == 0 ? null : valueSet.values.get(0), size);
     }
@@ -626,7 +628,7 @@ public static class BitSlicedPrimitiveArray implements Representation {
       return RepresentationType.BIT_SLICED_PRIMITIVE_ARRAY;
     }
 
-    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int[] sources) {
+    @Override public Object freeze(ColumnLoader.ValueSet valueSet, int @Nullable [] sources) {
       final int chunksPerWord = 64 / bitCount;
       final List<Comparable> valueList =
           permuteList(valueSet.values, sources);
@@ -783,7 +785,7 @@ public static void orLong(
   }
 
   private static <E> List<E> permuteList(
-      final List<E> list, final int[] sources) {
+      final List<E> list, final int @Nullable [] sources) {
     if (sources == null) {
       return list;
     }
@@ -828,13 +830,13 @@ public <T> Enumerator<T> enumerator() {
       }
     }
 
-    public Enumerator<Object[]> arrayEnumerator() {
+    public Enumerator<@Nullable Object[]> arrayEnumerator() {
       return new ArrayEnumerator(size, columns);
     }
 
     /** Enumerator over a table with a single column; each element
      * returned is an object. */
-    private static class ObjectEnumerator implements Enumerator<Object> {
+    private static class ObjectEnumerator implements Enumerator<@Nullable Object> {
       final int rowCount;
       final Object dataSet;
       final Representation representation;
@@ -846,7 +848,7 @@ private static class ObjectEnumerator implements Enumerator<Object> {
         this.representation = column.representation;
       }
 
-      @Override public Object current() {
+      @Override public @Nullable Object current() {
         return representation.getObject(dataSet, i);
       }
 
@@ -864,7 +866,7 @@ private static class ObjectEnumerator implements Enumerator<Object> {
 
     /** Enumerator over a table with more than one column; each element
      * returned is an array. */
-    private static class ArrayEnumerator implements Enumerator<Object[]> {
+    private static class ArrayEnumerator implements Enumerator<@Nullable Object[]> {
       final int rowCount;
       final List<Column> columns;
       int i = -1;
@@ -874,8 +876,8 @@ private static class ArrayEnumerator implements Enumerator<Object[]> {
         this.columns = columns;
       }
 
-      @Override public Object[] current() {
-        Object[] objects = new Object[columns.size()];
+      @Override public @Nullable Object[] current() {
+        @Nullable Object[] objects = new Object[columns.size()];
         for (int j = 0; j < objects.length; j++) {
           final Column pair = columns.get(j);
           objects[j] = pair.representation.getObject(pair.dataSet, i);

core/src/main/java/org/apache/calcite/adapter/clone/ColumnLoader.java

@@ -27,6 +27,8 @@
 import org.apache.calcite.rel.type.RelProtoDataType;
 import org.apache.calcite.util.Util;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 import java.lang.reflect.Type;
 import java.sql.Date;
 import java.sql.Time;
@@ -62,6 +64,7 @@ class ColumnLoader<T> {
    * @param sourceTable Source data
    * @param protoRowType Logical row type
    * @param repList Physical row types, or null if not known */
+  @SuppressWarnings("method.invocation.invalid")
   ColumnLoader(JavaTypeFactory typeFactory,
       Enumerable<T> sourceTable,
       RelProtoDataType protoRowType,
@@ -195,7 +198,7 @@ private void load(final RelDataType elementType,
         // We have discovered a the first unique key in the table.
         sort[0] = pair.i;
         final Comparable[] values =
-            valueSet.values.toArray(new Comparable[list.size()]);
+            valueSet.values.toArray(new Comparable[0]);
         final Kev[] kevs = new Kev[list.size()];
         for (int i = 0; i < kevs.length; i++) {
           kevs[i] = new Kev(i, values[i]);
@@ -230,15 +233,16 @@ private void load(final RelDataType elementType,
    * value needs to be converted to a {@link Long}. Similarly
    * {@link java.sql.Date} and {@link java.sql.Time} values to
    * {@link Integer}. */
-  private static List wrap(ColumnMetaData.Rep rep, List list,
+  private static List<? extends @Nullable Object> wrap(ColumnMetaData.Rep rep, List<?> list,
       RelDataType type) {
     switch (type.getSqlTypeName()) {
     case TIMESTAMP:
       switch (rep) {
       case OBJECT:
       case JAVA_SQL_TIMESTAMP:
-        return Util.transform(list,
+        final List<@Nullable Long> longs = Util.transform((List<@Nullable Timestamp>) list,
             (Timestamp t) -> t == null ? null : t.getTime());
+        return longs;
       default:
         break;
       }
@@ -247,7 +251,7 @@ private static List wrap(ColumnMetaData.Rep rep, List list,
       switch (rep) {
       case OBJECT:
       case JAVA_SQL_TIME:
-        return Util.transform(list, (Time t) -> t == null
+        return Util.transform((List<@Nullable Time>) list, (Time t) -> t == null
             ? null
             : (int) (t.getTime() % DateTimeUtils.MILLIS_PER_DAY));
       default:
@@ -258,9 +262,10 @@ private static List wrap(ColumnMetaData.Rep rep, List list,
       switch (rep) {
       case OBJECT:
       case JAVA_SQL_DATE:
-        return Util.transform(list, (Date d) -> d == null
-            ? null
-            : (int) (d.getTime() / DateTimeUtils.MILLIS_PER_DAY));
+        return Util.<@Nullable Date, @Nullable Integer>transform(
+            (List<@Nullable Date>) list, (Date d) -> d == null
+                ? null
+                : (int) (d.getTime() / DateTimeUtils.MILLIS_PER_DAY));
       default:
         break;
       }
@@ -279,15 +284,15 @@ static class ValueSet {
     final Class clazz;
     final Map<Comparable, Comparable> map = new HashMap<>();
     final List<Comparable> values = new ArrayList<>();
-    Comparable min;
-    Comparable max;
+    @Nullable Comparable min;
+    @Nullable Comparable max;
     boolean containsNull;
 
     ValueSet(Class clazz) {
       this.clazz = clazz;
     }
 
-    void add(Comparable e) {
+    void add(@Nullable Comparable e) {
       if (e != null) {
         final Comparable old = e;
         e = map.get(e);
@@ -367,7 +372,7 @@ private long toLong(Object o) {
       }
     }
 
-    private boolean canBeLong(Object o) {
+    private boolean canBeLong(@Nullable Object o) {
       return o instanceof Boolean
           || o instanceof Character
           || o instanceof Number;

core/src/main/java/org/apache/calcite/adapter/enumerable/AggAddContext.java

@@ -19,6 +19,8 @@
 import org.apache.calcite.linq4j.tree.Expression;
 import org.apache.calcite.rex.RexNode;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 import java.util.List;
 
 /**
@@ -41,7 +43,7 @@ public interface AggAddContext extends AggResultContext {
    * Returns {@link org.apache.calcite.rex.RexNode} representation of the
    * filter, or null.
    */
-  RexNode rexFilterArgument();
+  @Nullable RexNode rexFilterArgument();
 
   /**
    * Returns Linq4j form of arguments.

core/src/main/java/org/apache/calcite/adapter/enumerable/AggImpState.java

@@ -19,6 +19,8 @@
 import org.apache.calcite.linq4j.tree.Expression;
 import org.apache.calcite.rel.core.AggregateCall;
 
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+
 import java.util.List;
 
 /**
@@ -28,21 +30,21 @@ public class AggImpState {
   public final int aggIdx;
   public final AggregateCall call;
   public final AggImplementor implementor;
-  public AggContext context;
-  public Expression result;
-  public List<Expression> state;
-  public Expression accumulatorAdder;
+  public @MonotonicNonNull AggContext context;
+  public @MonotonicNonNull Expression result;
+  public @MonotonicNonNull List<Expression> state;
+  public @MonotonicNonNull Expression accumulatorAdder;
 
   public AggImpState(int aggIdx, AggregateCall call, boolean windowContext) {
     this.aggIdx = aggIdx;
     this.call = call;
-    this.implementor =
-        RexImpTable.INSTANCE.get(call.getAggregation(), windowContext);
+    AggImplementor implementor = RexImpTable.INSTANCE.get(call.getAggregation(), windowContext);
     if (implementor == null) {
       throw new IllegalArgumentException(
           "Unable to get aggregate implementation for aggregate "
           + call.getAggregation()
           + (windowContext ? " in window context" : ""));
     }
+    this.implementor = implementor;
   }
 }

core/src/main/java/org/apache/calcite/adapter/enumerable/AggResultContext.java

@@ -19,6 +19,8 @@
 import org.apache.calcite.linq4j.tree.Expression;
 import org.apache.calcite.rel.core.AggregateCall;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * Information for a call to
  * {@link AggImplementor#implementResult(AggContext, AggResultContext)}
@@ -32,7 +34,7 @@ public interface AggResultContext extends NestedBlockBuilder, AggResetContext {
    * accumulator were aggregated. Most aggregate functions depend on only the
    * accumulator, but quasi-aggregate functions such as GROUPING access at the
    * key. */
-  Expression key();
+  @Nullable Expression key();
 
   /** Returns an expression that references the {@code i}th field of the key,
    * cast to the appropriate type. */