Use pattern matching for instanceof in iceberg connector

[krvikash]

Description

Use pattern matching for instanceof in iceberg connector

Pattern matching for instanceof introduced in Java 16 (https://openjdk.org/jeps/394)

Motivation (copied from https://openjdk.org/jeps/394)
Nearly every program includes some sort of logic that combines testing if an expression has a certain type or structure, and then conditionally extracting components of its state for further processing. For example, all Java programmers are familiar with the instanceof-and-cast idiom:

if (obj instanceof String) {
    String s = (String) obj;    // grr...
    ...
}

There are three things going on here: a test (is obj a String?), a conversion (casting obj to String), and the declaration of a new local variable (s) so that we can use the string value. This pattern is straightforward and understood by all Java programmers, but is suboptimal for several reasons. It is tedious; doing both the type test and cast should be unnecessary (what else would you do after an instanceof test?). This boilerplate — in particular, the three occurrences of the type String — obfuscates the more significant logic that follows. But most importantly, the repetition provides opportunities for errors to creep unnoticed into programs.

Rather than reach for ad-hoc solutions, we believe it is time for Java to embrace pattern matching. Pattern matching allows the desired "shape" of an object to be expressed concisely (the pattern), and for various statements and expressions to test that "shape" against their input (the matching). Many languages, from Haskell to C#, have embraced pattern matching for its brevity and safety.

Additional context and related issues

NA

Release notes

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# Section
* Fix some things. ({issue}`issuenumber`)

[findinpath]

Do address also:

• trino/plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergAvroDataConversion.java

  Line 163 in 9a74942

  DecimalType decimalType = (DecimalType) type;

• trino/plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergAvroDataConversion.java

  Lines 313 to 315 in 9a74942

  	if (type instanceof ArrayType) {
  	Collection<?> array = (Collection<?>) object;
  	Type elementType = ((ArrayType) type).getElementType();

• trino/plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergAvroDataConversion.java

  Lines 324 to 327 in 9a74942

  	if (type instanceof MapType) {
  	Map<?, ?> map = (Map<?, ?>) object;
  	Type keyType = ((MapType) type).getKeyType();
  	Type valueType = ((MapType) type).getValueType();

• trino/plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergPageSourceProvider.java

  Lines 744 to 745 in 9a74942

  	if (e instanceof TrinoException) {
  	throw (TrinoException) e;

• trino/plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergPageSourceProvider.java

  Lines 840 to 841 in 9a74942

  	if (columnType instanceof ArrayType) {
  	return new ArrayType(getOrcReadType(((ArrayType) columnType).getElementType(), typeManager));

• trino/plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergPageSourceProvider.java

  Lines 843 to 844 in 9a74942

  	if (columnType instanceof MapType) {
  	MapType mapType = (MapType) columnType;

[ebyhr]

CI hit #15293