[jOOQ/jOOQ#9506] Added org.jooq.Versions as a result type for VersionProvider

jOOQ/src/main/java/org/jooq/VersionProvider.java

@@ -37,8 +37,6 @@
  */
 package org.jooq;
 
-import java.util.Set;
-
 /**
  * An SPI that allows for providing a graph of versions.
  *
@@ -55,6 +53,5 @@ public interface VersionProvider {
      * {@link Version#migrateTo(Version)} and other operations are undefined
      * if two versions do not have a common ancestor.
      */
-    @Internal // TODO Produce a better type than Set<Version>. Possibly, #current() can be obtained from the new result type.
-    Set<Version> provide();
+    Versions provide();
 }

jOOQ/src/main/java/org/jooq/Versions.java

@@ -0,0 +1,57 @@
+/*
+ * Licensed 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.
+ *
+ * Other licenses:
+ * -----------------------------------------------------------------------------
+ * Commercial licenses for this work are available. These replace the above
+ * ASL 2.0 and offer limited warranties, support, maintenance, and commercial
+ * database integrations.
+ *
+ * For more information, please visit: http://www.jooq.org/licenses
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ */
+package org.jooq;
+
+/**
+ * A directed, acyclic graph of {@link Version} objects
+ *
+ * @author Lukas Eder
+ */
+public interface Versions {
+
+    /**
+     * The root version of this graph.
+     */
+    Version root();
+
+    /**
+     * Find a version by its id, or <code>null</code>, if no such version was
+     * found.
+     */
+    Version get(String id);
+}

jOOQ/src/main/java/org/jooq/impl/DefaultVersionProvider.java

@@ -37,15 +37,13 @@
  */
 package org.jooq.impl;
 
-import java.util.LinkedHashSet;
-import java.util.Set;
-
 import org.jooq.Configuration;
 import org.jooq.DSLContext;
 import org.jooq.Parser;
 import org.jooq.Source;
 import org.jooq.Version;
 import org.jooq.VersionProvider;
+import org.jooq.Versions;
 
 /**
  * A default implementation of the {@link VersionProvider} SPI, which provides
@@ -67,10 +65,9 @@ public class DefaultVersionProvider implements VersionProvider {
     }
 
     @Override
-    public Set<Version> provide() {
-        Set<Version> result = new LinkedHashSet<>();
+    public Versions provide() {
         Version parent;
-        result.add(parent = ctx.version("initial"));
+        VersionsImpl result = new VersionsImpl(parent = ctx.version("initial"));
 
         Parser parser = ctx.parser();
         for (int i = 0; i < sources.length; i++)

jOOQ/src/main/java/org/jooq/impl/MigrationImpl.java

@@ -54,10 +54,8 @@ import static org.jooq.impl.MigrationImpl.Status.SUCCESS;
 import java.sql.Timestamp;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
-import java.util.Map;
 import java.util.Set;
 
 import org.jooq.Configuration;
@@ -77,6 +75,7 @@ import org.jooq.Table;
 import org.jooq.TableField;
 import org.jooq.UniqueKey;
 import org.jooq.Version;
+import org.jooq.Versions;
 import org.jooq.conf.InterpreterSearchSchema;
 import org.jooq.exception.DataAccessException;
 import org.jooq.exception.DataMigrationException;
@@ -96,7 +95,7 @@ final class MigrationImpl extends AbstractScope implements Migration {
     private final Version                        to;
     private Version                              from;
     private Queries                              queries;
-    private Map<String, Version>                 versions;
+    private Versions                             versions;
 
     MigrationImpl(Configuration configuration, Version to) {
         super(configuration.derive(new ThreadLocalTransactionProvider(configuration.systemConnectionProvider())));
@@ -127,13 +126,9 @@ final class MigrationImpl extends AbstractScope implements Migration {
         return queries;
     }
 
-    private final Map<String, Version> versions() {
-        if (versions == null) {
-            versions = new HashMap<>();
-
-            for (Version version : configuration().versionProvider().provide())
-                versions.put(version.id(), version);
-        }
+    private final Versions versions() {
+        if (versions == null)
+            versions = configuration().versionProvider().provide();
 
         return versions;
     }
@@ -159,7 +154,7 @@ final class MigrationImpl extends AbstractScope implements Migration {
     }
 
     private final void validateVersionProvider(Version version) {
-        if (!versions().containsKey(version.id()))
+        if (versions().get(version.id()) == null)
             throw new DataMigrationValidationException("Version is not available from VersionProvider: " + version.id());
     }
 

jOOQ/src/main/java/org/jooq/impl/VersionsImpl.java

@@ -0,0 +1,84 @@
+/*
+ * Licensed 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.
+ *
+ * Other licenses:
+ * -----------------------------------------------------------------------------
+ * Commercial licenses for this work are available. These replace the above
+ * ASL 2.0 and offer limited warranties, support, maintenance, and commercial
+ * database integrations.
+ *
+ * For more information, please visit: http://www.jooq.org/licenses
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ */
+package org.jooq.impl;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.jooq.Version;
+import org.jooq.Versions;
+
+/**
+ * @author Lukas Eder
+ */
+final class VersionsImpl implements Versions {
+
+    final Version              root;
+    final Map<String, Version> versions;
+
+    VersionsImpl(Version root) {
+        this.root = root;
+        this.versions = new HashMap<>();
+
+        add(root);
+    }
+
+    void add(Version version) {
+        versions.put(version.id(), version);
+    }
+
+    void addAll(Collection<? extends Version> v) {
+        for (Version version : v)
+            add(version);
+    }
+
+    void remove(Version version) {
+        versions.remove(version.id());
+    }
+
+    @Override
+    public final Version root() {
+        return root;
+    }
+
+    @Override
+    public final Version get(String id) {
+        return versions.get(id);
+    }
+}