Aggregated parameter implementation

Author: todvora

src/main/java/com/github/joschi/jadconfig/AggregatedParameter.java

@@ -0,0 +1,21 @@
+package com.github.joschi.jadconfig;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * This annotation is intended to collect all configuration properties starting with the same prefix.
+ * Think opensearch.path.repo and opensearch.node.roles values aggregated as a {@code Map<String,String>}
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.FIELD)
+public @interface AggregatedParameter {
+    /**
+     * The prefix that will be used to match configuration properties. There is no preprocessing and it will be used
+     * as defined. So if you want to match opensearch.path.repo and opensearch.node.roles, your prefix should be
+     * {@code opensearch.}
+     */
+    String prefix();
+}

src/main/java/com/github/joschi/jadconfig/JadConfig.java

@@ -20,6 +20,7 @@
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.function.Function;
 import java.util.stream.Collectors;
 
 
@@ -202,6 +203,27 @@ private void processClassField(Object configurationBean, Field field) throws Val
                 throw new ParameterException("Couldn't set field " + field.getName(), e);
             }
         }
+
+        processPrefixParameter(configurationBean, field);
+    }
+
+    private void processPrefixParameter(Object configurationBean, Field field) {
+        AggregatedParameter parameter = field.getAnnotation(AggregatedParameter.class);
+        if (parameter != null) {
+            LOG.debug("Processing prefixed field {}", field);
+            final Map<String, String> params = repositories.stream().flatMap(r -> collectPrefixedParams(r, parameter.prefix()).entrySet().stream()).collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+            try {
+                field.setAccessible(true);
+                field.set(configurationBean, params);
+            } catch (IllegalAccessException e) {
+                throw new ParameterException("Couldn't set field " + field.getName(), e);
+            }
+        }
+    }
+
+    private Map<String, String> collectPrefixedParams(Repository repository, String prefix) {
+        final Collection<String> names = repository.readNames(prefix);
+        return names.stream().collect(Collectors.toMap(Function.identity(), repository::read));
     }
 
     private String lookupFallbackParameter(Parameter parameter) {

src/main/java/com/github/joschi/jadconfig/Repository.java

@@ -1,5 +1,7 @@
 package com.github.joschi.jadconfig;
 
+import java.util.Collection;
+
 /**
  * Interface for configuration repositories
  * <p>A configuration repository can be any data source containing configuration data,
@@ -25,6 +27,8 @@ public interface Repository {
      */
     String read(String name);
 
+    Collection<String> readNames(String prefix);
+
     /**
      * Closes the underlying data source when it isn't require any more.
      *

src/main/java/com/github/joschi/jadconfig/repositories/EnvironmentRepository.java

@@ -3,6 +3,9 @@
 import com.github.joschi.jadconfig.Repository;
 import com.github.joschi.jadconfig.RepositoryException;
 
+import java.util.Collection;
+import java.util.stream.Collectors;
+
 /**
  * {@link Repository} class providing access to environment variables.
  * <p/>
@@ -75,6 +78,20 @@ public String read(final String name) {
         return System.getenv(envName);
     }
 
+    @Override
+    public Collection<String> readNames(String namePrefix) {
+
+        final String envName;
+
+        if (upperCase) {
+            envName = (prefix + namePrefix).toUpperCase();
+        } else {
+            envName = prefix + namePrefix;
+        }
+
+        return System.getenv().keySet().stream().filter(e -> e.startsWith(envName)).collect(Collectors.toSet());
+    }
+
     @Override
     public void close() throws RepositoryException {
         // NOP

src/main/java/com/github/joschi/jadconfig/repositories/InMemoryRepository.java

@@ -3,8 +3,10 @@
 import com.github.joschi.jadconfig.Repository;
 import com.github.joschi.jadconfig.RepositoryException;
 
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 /**
  * {@link Repository} class providing access to a simple configuration repository backed by {@link HashMap}
@@ -42,6 +44,11 @@ public String read(String name) {
         return properties.get(name);
     }
 
+    @Override
+    public Collection<String> readNames(String prefix) {
+        return properties.keySet().stream().filter(key -> key.startsWith(prefix)).collect(Collectors.toSet());
+    }
+
     @Override
     public void close() throws RepositoryException {
 

src/main/java/com/github/joschi/jadconfig/repositories/PropertiesRepository.java

@@ -7,7 +7,9 @@
 import java.io.FileReader;
 import java.io.IOException;
 import java.io.Reader;
+import java.util.Collection;
 import java.util.Properties;
+import java.util.stream.Collectors;
 
 /**
  * {@link Repository} class providing access to a configuration repository backed by {@link Properties} files
@@ -100,6 +102,11 @@ public String read(String name) {
         return PROPERTIES.getProperty(name);
     }
 
+    @Override
+    public Collection<String> readNames(String prefix) {
+        return PROPERTIES.stringPropertyNames().stream().filter(name -> name.startsWith(prefix)).collect(Collectors.toSet());
+    }
+
     /**
      * Close the underlying properties file.
      *

src/main/java/com/github/joschi/jadconfig/repositories/SystemPropertiesRepository.java

@@ -3,6 +3,9 @@
 import com.github.joschi.jadconfig.Repository;
 import com.github.joschi.jadconfig.RepositoryException;
 
+import java.util.Collection;
+import java.util.stream.Collectors;
+
 /**
  * {@link Repository} class providing access to System properties.
  * <p/>
@@ -46,6 +49,11 @@ public String read(String name) {
         return System.getProperty(prefix + name);
     }
 
+    @Override
+    public Collection<String> readNames(String prefix) {
+        return System.getProperties().stringPropertyNames().stream().filter(key -> key.startsWith(prefix)).collect(Collectors.toSet());
+    }
+
     @Override
     public void close() throws RepositoryException {
 

src/test/java/com/github/joschi/jadconfig/AggregatedPropertiesTest.java

@@ -0,0 +1,27 @@
+package com.github.joschi.jadconfig;
+
+import com.github.joschi.jadconfig.repositories.PropertiesRepository;
+import com.github.joschi.jadconfig.testbeans.SimpleConfigurationBean;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class AggregatedPropertiesTest {
+
+    private static final String PROPERTIES_FILE = PropertiesRepository.class.getResource("/testConfiguration.properties").getFile();
+
+    @Test
+    public void testPrefixProperties() throws ValidationException, RepositoryException {
+        final PropertiesRepository repository = new PropertiesRepository(PROPERTIES_FILE);
+
+        final SimpleConfigurationBean configurationBean = new SimpleConfigurationBean();
+        final JadConfig jadConfig = new JadConfig(repository, configurationBean);
+        jadConfig.process();
+
+        Assert.assertNotNull(configurationBean.getOpensearchProperties());
+        Assert.assertEquals(3, configurationBean.getOpensearchProperties().size());
+
+        Assert.assertEquals("search,cluster_manager", configurationBean.getOpensearchProperties().get("opensearch.node.roles"));
+        Assert.assertEquals("10gb", configurationBean.getOpensearchProperties().get("opensearch.node.search.cache.size"));
+        Assert.assertEquals("/tmp", configurationBean.getOpensearchProperties().get("opensearch.path.repo"));
+    }
+}

src/test/java/com/github/joschi/jadconfig/testbeans/SimpleConfigurationBean.java

@@ -1,12 +1,14 @@
 package com.github.joschi.jadconfig.testbeans;
 
 import com.github.joschi.jadconfig.Parameter;
+import com.github.joschi.jadconfig.AggregatedParameter;
 import com.github.joschi.jadconfig.converters.StringListConverter;
 
 import java.io.File;
 import java.net.URI;
 import java.nio.file.Path;
 import java.util.List;
+import java.util.Map;
 
 public class SimpleConfigurationBean {
 
@@ -58,6 +60,9 @@ public class SimpleConfigurationBean {
     @Parameter(value = "test.Nonexistent3", fallbackPropertyName = "test.fallback.secondary")
     private String myHardcodedDefaultString = "foobar";
 
+    @AggregatedParameter(prefix = "opensearch.")
+    private Map<String, String> opensearchProperties;
+
     public String getMyString() {
         return myString;
     }
@@ -121,4 +126,8 @@ public String getMyNonexistentString() {
     public String getMyHardcodedDefaultString() {
         return myHardcodedDefaultString;
     }
+
+    public Map<String, String> getOpensearchProperties() {
+        return opensearchProperties;
+    }
 }

src/test/resources/testConfiguration.properties

@@ -16,3 +16,6 @@ test.file=testConfiguration.properties
 test.path=testConfiguration.properties
 test.fallback.primary=prim
 test.fallback.secondary=sec
+opensearch.node.roles=search,cluster_manager
+opensearch.node.search.cache.size=10gb
+opensearch.path.repo=/tmp