[MOD] Types: unify sequence type caches

Author: ChristianGruen

basex-core/src/main/java/org/basex/query/value/type/BasicType.java

@@ -943,8 +943,8 @@ public QNm read(final DataInput in, final QueryContext qc) throws IOException {
 
   /** Pre/post values (pre, post << 8). */
   private short prePost;
-  /** Sequence types (can be {@code null}; lazy instantiation). */
-  private EnumMap<Occ, SeqType> seqTypes;
+  /** Sequence types. */
+  private final SeqType[] seqTypes = SeqType.cache(this);
   /** QName (can be {@code null}; lazy instantiation). */
   private QNm qnm;
 
@@ -1020,9 +1020,7 @@ public Item read(final DataInput in, final QueryContext qc) throws IOException,
 
   @Override
   public final SeqType seqType(final Occ occ) {
-    // cannot be instantiated statically due to circular dependencies
-    if(seqTypes == null) seqTypes = new EnumMap<>(Occ.class);
-    return seqTypes.computeIfAbsent(occ, o -> new SeqType(this, o));
+    return SeqType.get(seqTypes, this, occ);
   }
 
   /**

basex-core/src/main/java/org/basex/query/value/type/ChoiceItemType.java

@@ -22,8 +22,8 @@ public final class ChoiceItemType implements Type {
   /** Common ancestor type. */
   private final Type union;
 
-  /** Sequence types (can be {@code null}; lazy instantiation). */
-  private EnumMap<Occ, SeqType> seqTypes;
+  /** Sequence types. */
+  private final SeqType[] seqTypes = SeqType.cache(this);
 
   /**
    * Constructor.
@@ -79,9 +79,7 @@ public Item read(final DataInput in, final QueryContext qc) {
 
   @Override
   public SeqType seqType(final Occ occ) {
-    // cannot be instantiated statically due to circular dependencies
-    if(seqTypes == null) seqTypes = new EnumMap<>(Occ.class);
-    return seqTypes.computeIfAbsent(occ, o -> new SeqType(this, o));
+    return SeqType.get(seqTypes, this, occ);
   }
 
   @Override

basex-core/src/main/java/org/basex/query/value/type/EnumType.java

@@ -2,8 +2,6 @@
 
 import static org.basex.query.QueryError.*;
 
-import java.util.*;
-
 import org.basex.io.in.*;
 import org.basex.query.*;
 import org.basex.query.value.*;
@@ -22,8 +20,8 @@ public final class EnumType implements Type {
   /** The enumeration values (at least one). */
   private final TokenSet values;
 
-  /** Sequence types (can be {@code null}; lazy instantiation). */
-  private EnumMap<Occ, SeqType> seqTypes;
+  /** Sequence types. */
+  private final SeqType[] seqTypes = SeqType.cache(this);
 
   /**
    * Constructor.
@@ -80,9 +78,7 @@ public Item read(final DataInput in, final QueryContext qc) {
 
   @Override
   public SeqType seqType(final Occ occ) {
-    // cannot be instantiated statically due to circular dependencies
-    if(seqTypes == null) seqTypes = new EnumMap<>(Occ.class);
-    return seqTypes.computeIfAbsent(occ, o -> new SeqType(this, o));
+    return SeqType.get(seqTypes, this, occ);
   }
 
   @Override

basex-core/src/main/java/org/basex/query/value/type/FType.java

@@ -2,8 +2,6 @@
 
 import static org.basex.query.QueryError.*;
 
-import java.util.*;
-
 import org.basex.query.*;
 import org.basex.query.value.item.*;
 import org.basex.util.*;
@@ -19,8 +17,8 @@ public abstract class FType implements Type {
   /** Any function placeholder string. */
   static final String[] WILDCARD = { "*" };
 
-  /** Sequence types (can be {@code null}; lazy instantiation). */
-  private EnumMap<Occ, SeqType> seqTypes;
+  /** Sequence types. */
+  private final SeqType[] seqTypes = SeqType.cache(this);
 
   @Override
   public final boolean isNumber() {
@@ -49,9 +47,7 @@ public final boolean isSortable() {
 
   @Override
   public final SeqType seqType(final Occ occ) {
-    // cannot be instantiated statically due to circular dependencies
-    if(seqTypes == null) seqTypes = new EnumMap<>(Occ.class);
-    return seqTypes.computeIfAbsent(occ, o -> new SeqType(this, o));
+    return SeqType.get(seqTypes, this, occ);
   }
 
   @Override

basex-core/src/main/java/org/basex/query/value/type/ListType.java

@@ -5,8 +5,6 @@
 import static org.basex.util.Token.*;
 import static org.basex.util.Token.normalize;
 
-import java.util.*;
-
 import org.basex.io.in.*;
 import org.basex.query.*;
 import org.basex.query.value.*;
@@ -32,8 +30,8 @@ public enum ListType implements Type {
   /** Atom Type. */
   private final BasicType type;
 
-  /** Sequence types (can be {@code null}; lazy instantiation). */
-  private EnumMap<Occ, SeqType> seqTypes;
+  /** Sequence types. */
+  private final SeqType[] seqTypes = SeqType.cache(this);
 
   /**
    * Constructor.
@@ -118,9 +116,7 @@ public Item read(final DataInput in, final QueryContext qc) {
 
   @Override
   public SeqType seqType(final Occ occ) {
-    // cannot be instantiated statically due to circular dependencies
-    if(seqTypes == null) seqTypes = new EnumMap<>(Occ.class);
-    return seqTypes.computeIfAbsent(occ, o -> new SeqType(this, o));
+    return SeqType.get(seqTypes, this, occ);
   }
 
   @Override

basex-core/src/main/java/org/basex/query/value/type/NodeType.java

@@ -53,8 +53,8 @@ public final class NodeType implements Type {
   /** Node test (can be {@code null}). */
   public final Test test;
 
-  /** Sequence types (can be {@code null}; lazy instantiation). */
-  private EnumMap<Occ, SeqType> seqTypes;
+  /** Sequence types. */
+  private final SeqType[] seqTypes = SeqType.cache(this);
 
   /**
    * Constructor.
@@ -145,9 +145,7 @@ public GNode read(final DataInput in, final QueryContext qc) throws IOException,
 
   @Override
   public SeqType seqType(final Occ occ) {
-    // cannot be instantiated statically due to circular dependencies
-    if(seqTypes == null) seqTypes = new EnumMap<>(Occ.class);
-    return seqTypes.computeIfAbsent(occ, o -> new SeqType(this, o));
+    return SeqType.get(seqTypes, this, occ);
   }
 
   @Override

basex-core/src/main/java/org/basex/query/value/type/SeqType.java

@@ -24,6 +24,9 @@
  * @author Christian Gruen
  */
 public final class SeqType {
+  /** Number of cached sequence types (all occurrence indicators but {@link Occ#ZERO}). */
+  private static final int OCCS = Occ.values().length - 1;
+
   /** Item type. */
   public final Type type;
   /** Occurrence indicator. */
@@ -53,6 +56,35 @@ public static SeqType get(final Type type, final Occ occ) {
     return occ == ZERO ? Types.EMPTY_SEQUENCE_Z : type.seqType(occ);
   }
 
+  /**
+   * Creates a sequence type cache for the specified type.
+   * @param type item type
+   * @return cache
+   */
+  static SeqType[] cache(final Type type) {
+    final SeqType[] cache = new SeqType[OCCS];
+    cache[EXACTLY_ONE.ordinal() - 1] = new SeqType(type, EXACTLY_ONE);
+    return cache;
+  }
+
+  /**
+   * Returns a cached sequence type.
+   * @param cache sequence type cache
+   * @param type item type
+   * @param occ occurrence indicator (no {@link Occ#ZERO})
+   * @return sequence type
+   */
+  static SeqType get(final SeqType[] cache, final Type type, final Occ occ) {
+    assert occ != ZERO;
+    final int o = occ.ordinal() - 1;
+    SeqType st = cache[o];
+    if(st == null) {
+      st = new SeqType(type, occ);
+      cache[o] = st;
+    }
+    return st;
+  }
+
   /**
    * Returns an array type for this sequence type.
    * @return array type

basex-core/src/main/java/org/basex/query/value/type/TypeRef.java

@@ -22,8 +22,8 @@ public final class TypeRef implements Type {
   private InputInfo info;
   /** Referenced type (initially {@code item()}, may itself be a {@code TypeRef}). */
   private Type type = BasicType.ITEM;
-  /** Sequence types (can be {@code null}; lazy instantiation). */
-  private EnumMap<Occ, SeqType> seqTypes;
+  /** Sequence types. */
+  private final SeqType[] seqTypes = SeqType.cache(this);
 
   /**
    * Constructor.
@@ -123,8 +123,7 @@ public Item read(final DataInput in, final QueryContext qc) throws IOException,
   @Override
   public SeqType seqType(final Occ occ) {
     // wrap this placeholder, so that in-place resolution propagates to all use sites
-    if(seqTypes == null) seqTypes = new EnumMap<>(Occ.class);
-    return seqTypes.computeIfAbsent(occ, o -> new SeqType(this, o));
+    return SeqType.get(seqTypes, this, occ);
   }
 
   @Override

basex-core/src/main/java/org/basex/query/value/type/Types.java

@@ -19,7 +19,7 @@
  */
 public final class Types {
   /** Zero items (single instance). */
-  public static final SeqType EMPTY_SEQUENCE_Z = ITEM.seqType(ZERO);
+  public static final SeqType EMPTY_SEQUENCE_Z = new SeqType(ITEM, ZERO);
 
   /** Single item. */
   public static final SeqType ITEM_O = ITEM.seqType();