Core: add parsers for events and unbounded expressions

core/src/main/java/org/apache/iceberg/expressions/ExpressionParser.java

@@ -0,0 +1,312 @@
+/*
+ * 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 org.apache.iceberg.expressions;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import java.io.IOException;
+import java.io.StringWriter;
+import java.io.UncheckedIOException;
+import java.math.BigDecimal;
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
+import java.util.List;
+import java.util.Set;
+import java.util.UUID;
+import org.apache.iceberg.exceptions.RuntimeIOException;
+import org.apache.iceberg.relocated.com.google.common.collect.ImmutableSet;
+import org.apache.iceberg.relocated.com.google.common.collect.Lists;
+import org.apache.iceberg.types.Conversions;
+import org.apache.iceberg.types.Type;
+import org.apache.iceberg.types.Types;
+import org.apache.iceberg.util.JsonUtil;
+
+public class ExpressionParser {
+  private static final String TYPE = "type";
+  private static final String VALUE = "value";
+  private static final String OPERATION = "operation";
+  private static final String LITERALS = "literals";
+  private static final String TERM = "term";
+  private static final String LEFT_OPERAND = "left-operand";
+  private static final String RIGHT_OPERAND = "right-operand";
+  private static final String OPERAND = "operand";
+  private static final String UNBOUND_PREDICATE = "unbound-predicate";
+  private static final String BOUND_LITERAL_PREDICATE = "bound-literal-predicate";
+  private static final String BOUND_SET_PREDICATE = "bound-set-predicate";
+  private static final String BOUND_UNARY_PREDICATE = "bound-unary-predicate";
+  private static final String NAMED_REFERENCE = "named-reference";
+  private static final String BOUND_REFERENCE = "bound-reference";
+
+  private static final Set<Expression.Operation> ONE_INPUTS = ImmutableSet.of(
+          Expression.Operation.IS_NULL,
+          Expression.Operation.NOT_NULL,
+          Expression.Operation.IS_NAN,
+          Expression.Operation.NOT_NAN);
+
+  private ExpressionParser() {
+  }
+
+  public static String toJson(Expression expression, boolean pretty) {
+    try {
+      StringWriter writer = new StringWriter();
+      JsonGenerator generator = JsonUtil.factory().createGenerator(writer);
+      if (pretty) {
+        generator.useDefaultPrettyPrinter();
+      }
+      toJson(expression, generator);
+      generator.flush();
+      return writer.toString();
+
+    } catch (IOException e) {
+      throw new UncheckedIOException("Failed to write json", e);
+    }
+  }
+
+  public static void toJson(Expression expression, JsonGenerator generator) throws IOException {
+    if (expression instanceof And) {
+      toJson((And) expression, generator);
+    } else if (expression instanceof Or) {
+      toJson((Or) expression, generator);
+    } else if (expression instanceof Not) {
+      toJson((Not) expression, generator);
+    } else if (expression instanceof True) {
+      toJson((True) expression, generator);
+    } else if (expression instanceof False) {
+      toJson((False) expression, generator);
+    } else if (expression instanceof Predicate) {
+      toJson((Predicate<?, ?>) expression, generator);
+    } else {
+      throw new IllegalArgumentException("Invalid Operation Type");
+    }
+  }
+
+  private static void toJson(And expression, JsonGenerator generator) throws IOException {
+    generator.writeStartObject();
+    generator.writeStringField(OPERATION, Expression.Operation.AND.name().toLowerCase());
+    generator.writeFieldName(LEFT_OPERAND);
+    toJson(expression.left(), generator);
+    generator.writeFieldName(RIGHT_OPERAND);
+    toJson(expression.right(), generator);
+    generator.writeEndObject();
+  }
+
+  private static void toJson(Or expression, JsonGenerator generator) throws IOException {
+    generator.writeStartObject();
+    generator.writeStringField(OPERATION, Expression.Operation.OR.name().toLowerCase());
+    generator.writeFieldName(LEFT_OPERAND);
+    toJson(expression.left(), generator);
+    generator.writeFieldName(RIGHT_OPERAND);
+    toJson(expression.right(), generator);
+    generator.writeEndObject();
+  }
+
+  private static void toJson(Not expression, JsonGenerator generator) throws IOException {
+    generator.writeStartObject();
+    generator.writeStringField(OPERATION, Expression.Operation.NOT.name().toLowerCase());
+    generator.writeFieldName(OPERAND);
+    toJson(expression.child(), generator);
+    generator.writeEndObject();
+  }
+
+  private static void toJson(True expression, JsonGenerator generator) throws IOException {
+    generator.writeStartObject();
+    generator.writeStringField(OPERATION, Expression.Operation.TRUE.name().toLowerCase());
+    generator.writeEndObject();
+  }
+
+  private static void toJson(False expression, JsonGenerator generator) throws IOException {
+    generator.writeStartObject();
+    generator.writeStringField(OPERATION, Expression.Operation.FALSE.name().toLowerCase());
+    generator.writeEndObject();
+  }
+
+  private static void toJson(Predicate<?, ?> predicate, JsonGenerator generator) throws IOException {
+    if (predicate instanceof UnboundPredicate) {
+      toJson((UnboundPredicate<?>) predicate, generator);
+    } else {
+      throw new IllegalArgumentException("Cannot convert predicate " + predicate);
+    }
+  }
+
+  private static void toJson(UnboundPredicate<?> predicate, JsonGenerator generator) throws IOException {
+    generator.writeStartObject();
+    generator.writeStringField(OPERATION, UNBOUND_PREDICATE);
+    generator.writeStringField(TYPE, predicate.op().name().toLowerCase());
+    generator.writeFieldName(TERM);
+    toJson(predicate.term(), generator);
+    if (!ONE_INPUTS.contains(predicate.op())) {
+      generator.writeFieldName(LITERALS);
+      generator.writeStartArray();
+      for (Literal<?> literal : predicate.literals()) {
+        toJson(literal, generator);
+      }
+      generator.writeEndArray();
+    }
+
+    generator.writeEndObject();
+  }
+
+  private static void toJson(Term term, JsonGenerator generator) throws IOException {
+    if (term instanceof NamedReference) {
+      toJson((NamedReference<?>) term, generator);
+    } else {
+      throw new IllegalArgumentException("Cannot convert term " + term);
+    }
+  }
+
+  private static void toJson(NamedReference<?> term, JsonGenerator generator) throws IOException {
+    generator.writeStartObject();
+    generator.writeStringField(TYPE, NAMED_REFERENCE);
+    generator.writeStringField(VALUE, term.name());
+    generator.writeEndObject();
+  }
+
+  private static void toJson(Literal<?> literal, JsonGenerator generator) throws IOException {
+    generator.writeStartObject();
+
+    Object value = literal.value();
+    Type type;
+    if (value instanceof Boolean) {
+      type = Types.BooleanType.get();
+    } else if (value instanceof Integer) {
+      type = Types.IntegerType.get();
+    } else if (value instanceof Long) {
+      type = Types.LongType.get();
+    } else if (value instanceof Float) {
+      type = Types.FloatType.get();
+    } else if (value instanceof Double) {
+      type = Types.DoubleType.get();
+    } else if (value instanceof CharSequence) {
+      type = Types.StringType.get();
+    } else if (value instanceof UUID) {
+      type = Types.UUIDType.get();
+    } else if (value instanceof byte[]) {
+      type = Types.FixedType.ofLength(((byte[]) value).length);
+    } else if (value instanceof ByteBuffer) {
+      if (literal instanceof Literals.FixedLiteral) {
+        type = Types.FixedType.ofLength(((ByteBuffer) value).remaining());
+      } else {
+        type = Types.BinaryType.get();
+      }
+    } else if (value instanceof BigDecimal) {
+      BigDecimal decimal = (BigDecimal) value;
+      type = Types.DecimalType.of(decimal.precision(), decimal.scale());
+    } else {
+      throw new IllegalArgumentException("Cannot find literal type for value class " + value.getClass().getName());
+    }
+
+    generator.writeStringField(TYPE, type.toString());
+    generator.writeStringField(VALUE, StandardCharsets.UTF_8.decode(literal.toByteBuffer()).toString());
+    generator.writeEndObject();
+  }
+
+  public static Expression fromJson(String json) {
+    try {
+      ObjectMapper mapper = new ObjectMapper();
+      return fromJson(mapper.readTree(json));
+    } catch (IOException e) {
+      throw new RuntimeIOException(e);
+    }
+  }
+
+  public static Expression fromJson(JsonNode json) {
+    String expressionType;
+    if (json.hasNonNull(OPERATION)) {
+      expressionType = JsonUtil.getString(OPERATION, json);
+    } else {
+      return null;
+    }
+
+    if (Expression.Operation.AND.name().toLowerCase().equals(expressionType)) {
+      return new And(fromJson(json.get(LEFT_OPERAND)), fromJson(json.get(RIGHT_OPERAND)));
+    } else if (Expression.Operation.OR.name().toLowerCase().equals(expressionType)) {
+      return new Or(fromJson(json.get(LEFT_OPERAND)), fromJson(json.get(RIGHT_OPERAND)));
+    } else if (Expression.Operation.NOT.name().toLowerCase().equals(expressionType)) {
+      return new Not(fromJson(json.get(OPERAND)));
+    } else if (Expression.Operation.TRUE.name().toLowerCase().equals(expressionType)) {
+      return True.INSTANCE;
+    } else if (Expression.Operation.FALSE.name().toLowerCase().equals(expressionType)) {
+      return False.INSTANCE;
+    } else {
+      return fromJsonToPredicate(json, expressionType);
+    }
+  }
+
+  private static Predicate<?, ?> fromJsonToPredicate(JsonNode json, String predicateType) {
+    if (UNBOUND_PREDICATE.equals(predicateType)) {
+      return fromJsonUnboundPredicate(json);
+    } else if (BOUND_LITERAL_PREDICATE.equals(predicateType) ||
+            BOUND_SET_PREDICATE.equals(predicateType) ||
+            BOUND_UNARY_PREDICATE.equals(predicateType)) {
+      throw new UnsupportedOperationException(
+              "Serialization of Bound Predicates is not currently supported.");
+    } else {
+      throw new IllegalArgumentException("Invalid Predicate Type");
+    }
+  }
+
+  private static UnboundPredicate<?> fromJsonUnboundPredicate(JsonNode json) {
+    Expression.Operation operationType = Expression.Operation.valueOf(
+        JsonUtil.getString(TYPE, json).toUpperCase());
+
+    if (ONE_INPUTS.contains(operationType)) {
+      return new UnboundPredicate<>(operationType, fromJsonToTerm(json.get(TERM)));
+    } else {
+      return new UnboundPredicate(
+              operationType,
+          fromJsonToTerm(json.get(TERM)),
+          fromJsonToLiteralValues(json.get(LITERALS)));
+    }
+  }
+
+  private static UnboundTerm<?> fromJsonToTerm(JsonNode json) {
+    String referenceType = json.get(TYPE).textValue();
+
+    if (referenceType.equals(NAMED_REFERENCE)) {
+      return new NamedReference<>(json.get(VALUE).textValue());
+    } else if (referenceType.equals(BOUND_REFERENCE)) {
+      throw new UnsupportedOperationException(
+              "Serialization of Predicate type BoundReference is not currently supported.");
+    } else {
+      throw new IllegalArgumentException("Invalid Term Reference Type");
+    }
+  }
+
+  private static List<Object> fromJsonToLiteralValues(JsonNode json) {
+    List<Object> literals = Lists.newArrayList();
+    for (int i = 0; i < json.size(); i++) {
+      String literalType = json.get(i).get(TYPE).textValue();
+      Type primitiveType = Types.fromPrimitiveString(literalType);
+      Object value = Conversions.fromByteBuffer(
+              primitiveType,
+              StandardCharsets.UTF_8.encode(json.get(i).get(VALUE).textValue()));
+      if (primitiveType.typeId() == Type.TypeID.FIXED) {
+        byte[] valueByteArray = new byte[((ByteBuffer) value).remaining()];
+        ((ByteBuffer) value).get(valueByteArray);
+        value = valueByteArray;
+      }
+
+      literals.add(value);
+    }
+
+    return literals;
+  }
+}