Improve Property Mapping API

Previously the PutIfPresent API was a clunky way of only setting a property in
the PropertySource if the corresponding entry from the binding existed.  It
was pointed out in #31 that there are better APIs for doing this same thing.
Unfortunately the suggestion in that issue wasn't suitable (it was built for
beans not maps), but it did inspire a better API that was suited to maps.
This change implements that new API.

Signed-off-by: Ben Hale <bhale@vmware.com>

src/main/java/org/springframework/cloud/bindings/boot/CassandraBindingsPropertiesProcessor.java

@@ -23,7 +23,6 @@ import org.springframework.core.env.Environment;
 import java.util.Map;
 
 import static org.springframework.cloud.bindings.boot.Guards.isKindEnabled;
-import static org.springframework.cloud.bindings.boot.PutIfPresent.put;
 
 /**
  * An implementation of {@link BindingsPropertiesProcessor} that detects {@link Binding}s of kind: {@value KIND}.
@@ -42,16 +41,16 @@ public final class CassandraBindingsPropertiesProcessor implements BindingsPrope
         }
 
         bindings.filterBindings(KIND).forEach(binding -> {
-            Map<String, String> secret = binding.getSecret();
+            MapMapper map = new MapMapper(binding.getSecret(), properties);
 
-            put(properties, "spring.data.cassandra.cluster-name").ifPresent(secret, "cluster-name");
-            put(properties, "spring.data.cassandra.compression").ifPresent(secret, "compression");
-            put(properties, "spring.data.cassandra.contact-points").ifPresent(secret, "contact-points");
-            put(properties, "spring.data.cassandra.keyspace-name").ifPresent(secret, "keyspace-name");
-            put(properties, "spring.data.cassandra.password").ifPresent(secret, "password");
-            put(properties, "spring.data.cassandra.port").ifPresent(secret, "port");
-            put(properties, "spring.data.cassandra.ssl").ifPresent(secret, "ssl");
-            put(properties, "spring.data.cassandra.username").ifPresent(secret, "username");
+            map.from("cluster-name").to("spring.data.cassandra.cluster-name");
+            map.from("compression").to("spring.data.cassandra.compression");
+            map.from("contact-points").to("spring.data.cassandra.contact-points");
+            map.from("keyspace-name").to("spring.data.cassandra.keyspace-name");
+            map.from("password").to("spring.data.cassandra.password");
+            map.from("port").to("spring.data.cassandra.port");
+            map.from("ssl").to("spring.data.cassandra.ssl");
+            map.from("username").to("spring.data.cassandra.username");
         });
     }
 

src/main/java/org/springframework/cloud/bindings/boot/Db2BindingsPropertiesProcessor.java

@@ -43,13 +43,14 @@ public final class Db2BindingsPropertiesProcessor implements BindingsPropertiesP
         }
 
         bindings.filterBindings(KIND).forEach(binding -> {
-            Map<String, String> secret = binding.getSecret();
+            MapMapper map = new MapMapper(binding.getSecret(), properties);
+
+            map.from("password").to("spring.datasource.password");
+            map.from("host", "port", "database").to("spring.datasource.url",
+                    (host, port, database) -> String.format("jdbc:db2://%s:%s/%s", host, port, database));
+            map.from("username").to("spring.datasource.username");
 
             properties.put("spring.datasource.driver-class-name", "com.ibm.db2.jcc.DB2Driver");
-            properties.put("spring.datasource.password", secret.get("password"));
-            properties.put("spring.datasource.url", String.format("jdbc:db2://%s:%s/%s",
-                    secret.get("host"), secret.get("port"), secret.get("database")));
-            properties.put("spring.datasource.username", secret.get("username"));
         });
     }
 

src/main/java/org/springframework/cloud/bindings/boot/MapMapper.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * 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.
+ */
+
+package org.springframework.cloud.bindings.boot;
+
+import java.util.Arrays;
+import java.util.Map;
+import java.util.function.Function;
+
+final class MapMapper {
+
+    private final Map<String, String> source;
+
+    private final Map<String, Object> destination;
+
+    MapMapper(Map<String, String> source, Map<String, Object> destination) {
+        this.source = source;
+        this.destination = destination;
+    }
+
+    Source from(String... keys) {
+        return new Source(keys);
+    }
+
+    interface TriFunction<T, U, V, R> {
+        R apply(T t, U u, V v);
+    }
+
+    final class Source {
+
+        private final String[] keys;
+
+        private Source(String[] keys) {
+            this.keys = keys;
+        }
+
+        void to(String key) {
+            to(key, v -> v);
+        }
+
+        void to(String key, Function<String, Object> function) {
+            if (keys.length != 1) {
+                throw new IllegalStateException(
+                        String.format("source size %d cannot be transformed as one argument", keys.length));
+            }
+
+            if (!Arrays.stream(keys).allMatch(source::containsKey)) {
+                return;
+            }
+
+            destination.put(key, function.apply(source.get(keys[0])));
+        }
+
+        void to(String key, TriFunction<String, String, String, Object> function) {
+            if (keys.length != 3) {
+                throw new IllegalStateException(
+                        String.format("source size %d cannot be consumed as three arguments", keys.length));
+            }
+
+            if (!Arrays.stream(keys).allMatch(source::containsKey)) {
+                return;
+            }
+
+            destination.put(key, function.apply(source.get(keys[0]), source.get(keys[1]), source.get(keys[2])));
+        }
+
+    }
+
+}

src/main/java/org/springframework/cloud/bindings/boot/MongoDbBindingsPropertiesProcessor.java

@@ -41,9 +41,9 @@ public final class MongoDbBindingsPropertiesProcessor implements BindingsPropert
         }
 
         bindings.filterBindings(KIND).forEach(binding -> {
-            Map<String, String> secret = binding.getSecret();
+            MapMapper map = new MapMapper(binding.getSecret(), properties);
 
-            properties.put("spring.mongodb.uri", secret.get("uri"));
+            map.from("uri").to("spring.mongodb.uri");
         });
     }
 

src/main/java/org/springframework/cloud/bindings/boot/MySqlBindingsPropertiesProcessor.java

@@ -43,6 +43,14 @@ public final class MySqlBindingsPropertiesProcessor implements BindingsPropertie
         }
 
         bindings.filterBindings(KIND).forEach(binding -> {
+            MapMapper map = new MapMapper(binding.getSecret(), properties);
+
+            map.from("password").to("spring.datasource.password");
+            map.from("host", "port", "database").to("spring.datasource.url",
+                    (host, port, database) -> String.format("jdbc:mysql://%s:%s/%s", host, port, database));
+            map.from("username").to("spring.datasource.username");
+
+
             Map<String, String> secret = binding.getSecret();
 
             try {
@@ -55,11 +63,6 @@ public final class MySqlBindingsPropertiesProcessor implements BindingsPropertie
                 } catch (ClassNotFoundException ignored) {
                 }
             }
-
-            properties.put("spring.datasource.password", secret.get("password"));
-            properties.put("spring.datasource.url", String.format("jdbc:mysql://%s:%s/%s",
-                    secret.get("host"), secret.get("port"), secret.get("database")));
-            properties.put("spring.datasource.username", secret.get("username"));
         });
     }
 

src/main/java/org/springframework/cloud/bindings/boot/OracleBindingsPropertiesProcessor.java

@@ -43,13 +43,14 @@ public final class OracleBindingsPropertiesProcessor implements BindingsProperti
         }
 
         bindings.filterBindings(KIND).forEach(binding -> {
-            Map<String, String> secret = binding.getSecret();
+            MapMapper map = new MapMapper(binding.getSecret(), properties);
+
+            map.from("password").to("spring.datasource.password");
+            map.from("host", "port", "database").to("spring.datasource.url",
+                    (host, port, database) -> String.format("jdbc:oracle://%s:%s/%s", host, port, database));
+            map.from("username").to("spring.datasource.username");
 
             properties.put("spring.datasource.driver-class-name", "oracle.jdbc.OracleDriver");
-            properties.put("spring.datasource.password", secret.get("password"));
-            properties.put("spring.datasource.url", String.format("jdbc:oracle://%s:%s/%s",
-                    secret.get("host"), secret.get("port"), secret.get("database")));
-            properties.put("spring.datasource.username", secret.get("username"));
         });
     }
 

src/main/java/org/springframework/cloud/bindings/boot/PostgreSqlBindingsPropertiesProcessor.java

@@ -43,13 +43,14 @@ public final class PostgreSqlBindingsPropertiesProcessor implements BindingsProp
         }
 
         bindings.filterBindings(KIND).forEach(binding -> {
-            Map<String, String> secret = binding.getSecret();
+            MapMapper map = new MapMapper(binding.getSecret(), properties);
+
+            map.from("password").to("spring.datasource.password");
+            map.from("host", "port", "database").to("spring.datasource.url",
+                    (host, port, database) -> String.format("jdbc:postgres://%s:%s/%s", host, port, database));
+            map.from("username").to("spring.datasource.username");
 
             properties.put("spring.datasource.driver-class-name", "org.postgresql.Driver");
-            properties.put("spring.datasource.password", secret.get("password"));
-            properties.put("spring.datasource.url", String.format("jdbc:postgres://%s:%s/%s",
-                    secret.get("host"), secret.get("port"), secret.get("database")));
-            properties.put("spring.datasource.username", secret.get("username"));
         });
     }
 

src/main/java/org/springframework/cloud/bindings/boot/PropertyMapper.java

@@ -18,27 +18,15 @@ package org.springframework.cloud.bindings.boot;
 
 import java.util.Map;
 
-final class PutIfPresent {
+final class PropertyMapper {
+
+    private final Map<String, String> source;
 
     private final Map<String, Object> destination;
 
-    private final String key;
-
-    PutIfPresent(Map<String, Object> destination, String key) {
+    PropertyMapper(Map<String, String> source, Map<String, Object> destination) {
+        this.source = source;
         this.destination = destination;
-        this.key = key;
-    }
-
-    static PutIfPresent put(Map<String, Object> destination, String key) {
-        return new PutIfPresent(destination, key);
-    }
-
-    void ifPresent(Map<String, String> source, String key) {
-        if (!source.containsKey(key)) {
-            return;
-        }
-
-        destination.put(this.key, source.get(key));
     }
 
 }

src/main/java/org/springframework/cloud/bindings/boot/RedisBindingsPropertiesProcessor.java

@@ -41,11 +41,11 @@ public final class RedisBindingsPropertiesProcessor implements BindingsPropertie
         }
 
         bindings.filterBindings(KIND).forEach(binding -> {
-            Map<String, String> secret = binding.getSecret();
+            MapMapper map = new MapMapper(binding.getSecret(), properties);
 
-            properties.put("spring.redis.host", secret.get("host"));
-            properties.put("spring.redis.password", secret.get("password"));
-            properties.put("spring.redis.port", secret.get("port"));
+            map.from("host").to("spring.redis.host");
+            map.from("password").to("spring.redis.password");
+            map.from("port").to("spring.redis.port");
         });
     }
 

src/main/java/org/springframework/cloud/bindings/boot/SqlServerBindingsPropertiesProcessor.java

@@ -43,13 +43,14 @@ public final class SqlServerBindingsPropertiesProcessor implements BindingsPrope
         }
 
         bindings.filterBindings(KIND).forEach(binding -> {
-            Map<String, String> secret = binding.getSecret();
+            MapMapper map = new MapMapper(binding.getSecret(), properties);
+
+            map.from("password").to("spring.datasource.password");
+            map.from("host", "port", "database").to("spring.datasource.url",
+                    (host, port, database) -> String.format("jdbc:sqlserver://%s:%s/%s", host, port, database));
+            map.from("username").to("spring.datasource.username");
 
             properties.put("spring.datasource.driver-class-name", "com.microsoft.sqlserver.jdbc.SQLServerDriver");
-            properties.put("spring.datasource.password", secret.get("password"));
-            properties.put("spring.datasource.url", String.format("jdbc:sqlserver://%s:%s/%s",
-                    secret.get("host"), secret.get("port"), secret.get("database")));
-            properties.put("spring.datasource.username", secret.get("username"));
         });
     }
 

src/test/java/org/springframework/cloud/bindings/boot/MapMapperTest.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * 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.
+ */
+
+package org.springframework.cloud.bindings.boot;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DisplayName("Map Mapper test")
+final class MapMapperTest {
+
+    private final Map<String, Object> destination = new HashMap<>();
+
+    private final Map<String, String> source = new HashMap<>();
+
+    private final MapMapper map = new MapMapper(source, destination);
+
+    @Test
+    @DisplayName("puts if present")
+    void present() {
+        source.put("test-source-key", "test-source-value");
+
+        map.from("test-source-key").to("test-destination-key");
+
+        assertThat(destination).containsEntry("test-destination-key", "test-source-value");
+    }
+
+    @Test
+    @DisplayName("transforms source value")
+    void transformed() {
+        source.put("test-source-key", "test-source-value");
+
+        map.from("test-source-key").to("test-destination-key", s -> {
+            assertThat(s).isEqualTo("test-source-value");
+
+            return "test-destination-value";
+        });
+
+        assertThat(destination).containsEntry("test-destination-key", "test-destination-value");
+    }
+
+    @Test
+    @DisplayName("does not put if not present")
+    void notPresent() {
+        map.from("test-source-key").to("test-destination-key");
+
+        assertThat(destination).doesNotContainKey("test-destination-key");
+    }
+
+    @Test
+    @DisplayName("puts if all present")
+    void allPresent() {
+        source.put("test-source-key-1", "test-source-value-1");
+        source.put("test-source-key-2", "test-source-value-2");
+        source.put("test-source-key-3", "test-source-value-3");
+
+        map.from("test-source-key-1", "test-source-key-2", "test-source-key-3").to("test-destination-key", (a, b, c) -> {
+            assertThat(a).isEqualTo("test-source-value-1");
+            assertThat(b).isEqualTo("test-source-value-2");
+            assertThat(c).isEqualTo("test-source-value-3");
+
+            return "test-destination-value";
+        });
+
+        assertThat(destination).containsEntry("test-destination-key", "test-destination-value");
+    }
+
+    @Test
+    @DisplayName("does not put if not all present")
+    void notAllPresent() {
+        source.put("test-source-key-1", "test-source-value-1");
+        source.put("test-source-key-2", "test-source-value-2");
+
+        map.from("test-source-key-1", "test-source-key-2", "test-source-key-3").to("test-destination-key", (a, b, c) -> "test-destination-value");
+
+        assertThat(destination).doesNotContainKey("test-destination-key");
+    }
+
+}

src/test/java/org/springframework/cloud/bindings/boot/PutIfPresentTest.java

@@ -1,54 +0,0 @@
-/*
- * Copyright 2020 the original author or authors.
- *
- * 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.
- */
-
-package org.springframework.cloud.bindings.boot;
-
-import org.junit.jupiter.api.DisplayName;
-import org.junit.jupiter.api.Test;
-
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.Map;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.cloud.bindings.boot.PutIfPresent.put;
-
-@DisplayName("Put if present")
-final class PutIfPresentTest {
-
-    @Test
-    @DisplayName("puts if present")
-    void present() {
-        Map<String, String> source = Collections.singletonMap("test-source-key", "test-source-value");
-        Map<String, Object> destination = new HashMap<>();
-
-        put(destination, "test-destination-key").ifPresent(source, "test-source-key");
-
-        assertThat(destination).containsEntry("test-destination-key", "test-source-value");
-    }
-
-    @Test
-    @DisplayName("does not put if not present")
-    void notPresent() {
-        Map<String, String> source = Collections.emptyMap();
-        Map<String, Object> destination = new HashMap<>();
-
-        put(destination, "test-destination-key").ifPresent(source, "test-source-key");
-
-        assertThat(destination).doesNotContainKey("test-destination-key");
-    }
-
-}