Breaking change! Now DbMigrationGenerator::generate() method returns a list of strings.

build.gradle.kts

@@ -26,7 +26,7 @@ description = "pg-index-health build"
 
 allprojects {
     group = "io.github.mfvanek"
-    version = "0.9.6"
+    version = "0.10.0"
 
     repositories {
         mavenLocal()

pg-index-health-generator/src/main/java/io/github/mfvanek/pg/generator/AbstractDbMigrationGenerator.java

@@ -12,6 +12,7 @@
 
 import io.github.mfvanek.pg.model.table.TableNameAware;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
 import javax.annotation.Nonnull;
@@ -33,19 +34,16 @@ abstract class AbstractDbMigrationGenerator<T extends TableNameAware> implements
      */
     @Nonnull
     @Override
-    public final String generate(@Nonnull final List<T> rows) {
+    public final List<String> generate(@Nonnull final List<T> rows) {
         Objects.requireNonNull(rows, "rows cannot be null");
 
-        final StringBuilder queryBuilder = new StringBuilder();
-        for (int i = 0; i < rows.size(); ++i) {
-            if (i != 0) {
-                queryBuilder.append(System.lineSeparator())
-                        .append(System.lineSeparator());
-            }
-            generate(queryBuilder, rows.get(i));
+        final List<String> migrations = new ArrayList<>(rows.size());
+        for (final T row : rows) {
+            migrations.add(generate(row));
         }
-        return queryBuilder.toString();
+        return migrations;
     }
 
-    protected abstract void generate(@Nonnull StringBuilder queryBuilder, @Nonnull T row);
+    @Nonnull
+    protected abstract String generate(@Nonnull T row);
 }

pg-index-health-generator/src/main/java/io/github/mfvanek/pg/generator/ColumnWithSerialTypeMigrationGenerator.java

@@ -31,9 +31,10 @@ public ColumnWithSerialTypeMigrationGenerator(@Nonnull final GeneratingOptions o
     }
 
     @Override
-    protected void generate(@Nonnull final StringBuilder queryBuilder, @Nonnull final ColumnWithSerialType column) {
-        queryBuilder.append(dropDefaultValueGenerator.generate(column))
-                .append(System.lineSeparator())
-                .append(dropSequenceGenerator.generate(column));
+    @Nonnull
+    protected String generate(@Nonnull final ColumnWithSerialType column) {
+        return dropDefaultValueGenerator.generate(column) +
+                System.lineSeparator() +
+                dropSequenceGenerator.generate(column);
     }
 }

pg-index-health-generator/src/main/java/io/github/mfvanek/pg/generator/DbMigrationGenerator.java

@@ -26,11 +26,12 @@
 public interface DbMigrationGenerator<T extends TableNameAware> {
 
     /**
-     * Generates sql migration based on the specified rows.
+     * Generates sql migrations based on the specified rows.
      *
      * @param rows a set of data on the basis of which the sql migration will be generated
-     * @return generated sql migration
+     * @return a list of generated sql migrations
+     * @since 0.10.0
      */
     @Nonnull
-    String generate(@Nonnull List<T> rows);
+    List<String> generate(@Nonnull List<T> rows);
 }

pg-index-health-generator/src/main/java/io/github/mfvanek/pg/generator/ForeignKeyMigrationGenerator.java

@@ -29,7 +29,8 @@ public ForeignKeyMigrationGenerator(@Nonnull final GeneratingOptions options) {
     }
 
     @Override
-    protected void generate(@Nonnull final StringBuilder queryBuilder, @Nonnull final ForeignKey foreignKey) {
-        queryBuilder.append(generator.generate(foreignKey));
+    @Nonnull
+    protected String generate(@Nonnull final ForeignKey foreignKey) {
+        return generator.generate(foreignKey);
     }
 }

pg-index-health-generator/src/test/java/io/github/mfvanek/pg/generator/ColumnWithSerialTypeMigrationGeneratorTest.java

@@ -35,7 +35,8 @@ void forSingleColumn() {
         final ColumnWithSerialTypeMigrationGenerator generator = new ColumnWithSerialTypeMigrationGenerator(GeneratingOptions.builder().build());
 
         assertThat(generator.generate(List.of(column())))
-                .isEqualTo("alter table if exists s1.t1" + System.lineSeparator() +
+                .hasSize(1)
+                .containsExactly("alter table if exists s1.t1" + System.lineSeparator() +
                         "    alter column col1 drop default;" + System.lineSeparator() +
                         "drop sequence if exists s1.seq1;");
     }
@@ -46,13 +47,13 @@ void forSeveralColumns() {
         final ColumnWithSerialTypeMigrationGenerator generator = new ColumnWithSerialTypeMigrationGenerator(GeneratingOptions.builder().build());
 
         assertThat(generator.generate(List.of(column(), secondColumn)))
-                .isEqualTo("alter table if exists s1.t1" + System.lineSeparator() +
-                        "    alter column col1 drop default;" + System.lineSeparator() +
-                        "drop sequence if exists s1.seq1;" + System.lineSeparator() +
-                        System.lineSeparator() +
+                .hasSize(2)
+                .containsExactly("alter table if exists s1.t1" + System.lineSeparator() +
+                                "    alter column col1 drop default;" + System.lineSeparator() +
+                                "drop sequence if exists s1.seq1;",
                         "alter table if exists s2.t2" + System.lineSeparator() +
-                        "    alter column col2 drop default;" + System.lineSeparator() +
-                        "drop sequence if exists s2.seq2;");
+                                "    alter column col2 drop default;" + System.lineSeparator() +
+                                "drop sequence if exists s2.seq2;");
     }
 
     @Nonnull

pg-index-health-generator/src/test/java/io/github/mfvanek/pg/generator/ForeignKeyMigrationGeneratorTest.java

@@ -24,10 +24,10 @@ class ForeignKeyMigrationGeneratorTest {
     @Test
     void generateForSingleForeignKey() {
         final DbMigrationGenerator<ForeignKey> generator = new ForeignKeyMigrationGenerator(GeneratingOptions.builder().build());
-        final String result = generator.generate(List.of(nullableColumnWithSchema()));
+        final var result = generator.generate(List.of(nullableColumnWithSchema()));
         assertThat(result)
-                .isNotBlank()
-                .isEqualTo("/* table_with_very_very_very_long_name_column_with_very_very_very_long_name_without_nulls_idx */" + System.lineSeparator() +
+                .hasSize(1)
+                .containsExactly("/* table_with_very_very_very_long_name_column_with_very_very_very_long_name_without_nulls_idx */" + System.lineSeparator() +
                         "create index concurrently if not exists table_with_very_very_very_long_name_3202677_without_nulls_idx" + System.lineSeparator() +
                         "    on schema_name_that_should_be_omitted.table_with_very_very_very_long_name (column_with_very_very_very_long_name) " +
                         "where column_with_very_very_very_long_name is not null;");
@@ -36,19 +36,17 @@ void generateForSingleForeignKey() {
     @Test
     void generateForSeveralForeignKeys() {
         final DbMigrationGenerator<ForeignKey> generator = new ForeignKeyMigrationGenerator(GeneratingOptions.builder().build());
-        final String result = generator.generate(
-                List.of(severalColumnsWithNulls(), severalColumnsWithNulls(), nullableColumnWithSchema()));
+        final var result = generator.generate(List.of(severalColumnsWithNulls(), severalColumnsWithNulls(), nullableColumnWithSchema()));
         assertThat(result)
-                .isNotBlank()
-                .isEqualTo("create index concurrently if not exists custom_table_custom_column_1_custom_column_22_without_nulls_idx" + System.lineSeparator() +
-                        "    on custom_table (custom_column_1, custom_column_22) where custom_column_22 is not null;" + System.lineSeparator() +
-                        System.lineSeparator() +
+                .hasSize(3)
+                .containsExactly(
                         "create index concurrently if not exists custom_table_custom_column_1_custom_column_22_without_nulls_idx" + System.lineSeparator() +
-                        "    on custom_table (custom_column_1, custom_column_22) where custom_column_22 is not null;" + System.lineSeparator() +
-                        System.lineSeparator() +
+                                "    on custom_table (custom_column_1, custom_column_22) where custom_column_22 is not null;",
+                        "create index concurrently if not exists custom_table_custom_column_1_custom_column_22_without_nulls_idx" + System.lineSeparator() +
+                                "    on custom_table (custom_column_1, custom_column_22) where custom_column_22 is not null;",
                         "/* table_with_very_very_very_long_name_column_with_very_very_very_long_name_without_nulls_idx */" + System.lineSeparator() +
-                        "create index concurrently if not exists table_with_very_very_very_long_name_3202677_without_nulls_idx" + System.lineSeparator() +
-                        "    on schema_name_that_should_be_omitted.table_with_very_very_very_long_name (column_with_very_very_very_long_name) " +
-                        "where column_with_very_very_very_long_name is not null;");
+                                "create index concurrently if not exists table_with_very_very_very_long_name_3202677_without_nulls_idx" + System.lineSeparator() +
+                                "    on schema_name_that_should_be_omitted.table_with_very_very_very_long_name (column_with_very_very_very_long_name) " +
+                                "where column_with_very_very_very_long_name is not null;");
     }
 }