gplazma: grid add interface to abstract SourceBackedPredicateMap

Motivation:

The SourceBackedPredicateMap provides a concrete implementation of
access to (key-predicate,value) pairs.  However, to support new
approaches, it would be useful to allow alternative implementations of
this behaviour.

Modification:

Add an interface to abstract away concrete implementation.

Result:

No user- or admin observable changes.  Code is more flexible, in
preparation for future changes.

Target: master
Requires-notes: no
Requires-book: no
Patch: https://rb.dcache.org/r/13663/
Acked-by: Tigran Mkrtchyan

modules/gplazma2-grid/src/main/java/org/dcache/gplazma/plugins/AuthzDbPlugin.java

@@ -62,7 +62,7 @@ enum PrincipalType {UID, GID, LOGIN, USER, GROUP}
     private final ImmutableList<PrincipalType> _uidOrder;
     private final ImmutableList<PrincipalType> _gidOrder;
 
-    private final SourceBackedPredicateMap<String, UserAuthzInformation> _map;
+    private final PredicateMap<String, UserAuthzInformation> _map;
 
     public AuthzDbPlugin(Properties properties) throws IOException {
         String path = properties.getProperty(AUTHZDB);
@@ -84,7 +84,7 @@ public AuthzDbPlugin(Properties properties) throws IOException {
      *
      * @param map map of usernames to user information (e.q. uid/gid)
      */
-    AuthzDbPlugin(SourceBackedPredicateMap<String, UserAuthzInformation> map,
+    AuthzDbPlugin(PredicateMap<String, UserAuthzInformation> map,
           ImmutableList<PrincipalType> uidOrder,
           ImmutableList<PrincipalType> gidOrder) {
         _map = map;

modules/gplazma2-grid/src/main/java/org/dcache/gplazma/plugins/PredicateMap.java

@@ -0,0 +1,36 @@
+/* dCache - http://www.dcache.org/
+ *
+ * Copyright (C) 2022 Deutsches Elektronen-Synchrotron
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.dcache.gplazma.plugins;
+
+import java.util.List;
+
+/**
+ * Handle a list of items where each item is a key-predicate,value pair.  Each
+ * key-predicate may be matched against some key.
+ * @param <K> The type of the keys.
+ * @param <V> The type of the values.
+ */
+public interface PredicateMap<K, V> {
+
+    /**
+     * Provide a list of items that match the supplied key.
+     * @param key the key to search for matching items.
+     * @return A list of values that match the supplied key.
+     */
+    List<V> getValuesForPredicatesMatching(K key);
+}

modules/gplazma2-grid/src/main/java/org/dcache/gplazma/plugins/SourceBackedPredicateMap.java

@@ -18,7 +18,7 @@
  * @param <TValue> type of values
  * @author karsten
  */
-class SourceBackedPredicateMap<TKey, TValue> {
+class SourceBackedPredicateMap<TKey, TValue> implements PredicateMap<TKey, TValue> {
 
     private static final Logger _log = LoggerFactory.getLogger(SourceBackedPredicateMap.class);
 
@@ -38,6 +38,7 @@ protected SourceBackedPredicateMap(LineSource source,
      * @param key Key to be used to find corresponding values
      * @return Collection of matching values
      */
+    @Override
     public synchronized List<TValue> getValuesForPredicatesMatching(TKey key) {
 
         if (_source.hasChanged()) {

modules/gplazma2-grid/src/main/java/org/dcache/gplazma/plugins/VoRoleMapPlugin.java

@@ -35,7 +35,7 @@ public class VoRoleMapPlugin implements GPlazmaMappingPlugin {
     private static final String VOROLEMAP =
           "gplazma.vorolemap.file";
 
-    private final SourceBackedPredicateMap<NameRolePair, String> _map;
+    private final PredicateMap<NameRolePair, String> _map;
 
     public VoRoleMapPlugin(Properties properties) throws IOException {
         String path = properties.getProperty(VOROLEMAP);
@@ -51,7 +51,7 @@ public VoRoleMapPlugin(Properties properties) throws IOException {
      *
      * @param map map of dnfqans to usernames
      */
-    VoRoleMapPlugin(SourceBackedPredicateMap<NameRolePair, String> map) {
+    VoRoleMapPlugin(PredicateMap<NameRolePair, String> map) {
         _map = map;
     }
 

modules/gplazma2-grid/src/test/java/org/dcache/gplazma/plugins/AuthzDbPluginTest.java

@@ -36,13 +36,11 @@ public class AuthzDbPluginTest {
     private final static URL TEST_FIXTURE =
           Resources.getResource("org/dcache/gplazma/plugins/authzdb.fixture");
 
-    private SourceBackedPredicateMap<String, UserAuthzInformation> testFixture;
+    private PredicateMap<String, UserAuthzInformation> testFixture;
 
     @Before
-    public void setup()
-          throws IOException {
-        testFixture =
-              new SourceBackedPredicateMap<>(new MemoryLineSource(
+    public void setup() throws IOException {
+        testFixture = new SourceBackedPredicateMap<>(new MemoryLineSource(
                     Resources.readLines(TEST_FIXTURE, Charset.defaultCharset())),
                     new AuthzMapLineParser());
     }

modules/gplazma2-grid/src/test/java/org/dcache/gplazma/plugins/CachedAuthzMapTest.java

@@ -24,8 +24,7 @@ public class CachedAuthzMapTest {
     private final static URL TEST_FIXTURE =
           Resources.getResource("org/dcache/gplazma/plugins/authzdb-parser.fixture");
 
-    private SourceBackedPredicateMap<String, UserAuthzInformation>
-    loadFixture(URL fixture)
+    private PredicateMap<String, UserAuthzInformation> loadFixture(URL fixture)
           throws IOException {
         return new SourceBackedPredicateMap<>(
               new MemoryLineSource(Resources.readLines(fixture, Charset.defaultCharset())),

modules/gplazma2-grid/src/test/java/org/dcache/gplazma/plugins/CachedVOMapTest.java

@@ -31,8 +31,7 @@ public class CachedVOMapTest {
     private final static URL TEST_FIXTURE_NDGF =
           Resources.getResource("org/dcache/gplazma/plugins/vorolemap-ndgf.fixture");
 
-    private SourceBackedPredicateMap<NameRolePair, String>
-    loadFixture(URL fixture)
+    private PredicateMap<NameRolePair, String> loadFixture(URL fixture)
           throws IOException {
         return new SourceBackedPredicateMap<>(
               new MemoryLineSource(Resources.readLines(fixture, Charset.defaultCharset())),

modules/gplazma2-grid/src/test/java/org/dcache/gplazma/plugins/VoRoleMapPluginTest.java

@@ -348,7 +348,7 @@ private void whenMapPluginCalledWith(Set<Principal> principals) throws Authentic
 
         VOMapLineParser parser = new VOMapLineParser();
 
-        SourceBackedPredicateMap<NameRolePair, String> map =
+        PredicateMap<NameRolePair, String> map =
               new SourceBackedPredicateMap<>(_source,
                     parser);