Initial Commit

src/main/java/net/locusworks/common/configuration/PropertiesManager.java

@@ -0,0 +1,125 @@
+package net.locusworks.common.configuration;
+
+import static net.locusworks.common.Charsets.UTF_8;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.Map;
+import java.util.Properties;
+import java.util.stream.Collectors;
+
+import net.locusworks.common.immutables.Pair;
+/**
+ * Properties manager class to help load and read properties
+ * @author Isaac Parenteau
+ * @version 1.0.0
+ * @date 02/15/2018
+ */
+public class PropertiesManager {
+  /**
+   * Load a configuration from resource
+   * @param clazz class loader
+   * @param src source of the file
+   * @return properties
+   * @throws IOException Exception thrown the file can't be read
+   */
+  public static Properties loadConfiguration(Class<?> clazz, String src) throws IOException {
+    InputStream is = clazz.getResourceAsStream(src);
+    if (is == null) {
+      is = clazz.getClassLoader().getResourceAsStream(src);
+    }
+    if (is == null) {
+      return null;
+    }
+    BufferedReader br = new BufferedReader(new InputStreamReader(is, UTF_8));
+    return loadConfiguration(br);
+  }
+
+  /**
+   * Load configuration from a file
+   * @param file File to load
+   * @return properties
+   * @throws IOException Exception thrown the file can't be read
+   */
+  public static Properties loadConfiguration(File file) throws IOException {
+    if (!file.exists()) {
+      return new Properties();
+    }
+    BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file), UTF_8));
+    return loadConfiguration(br);
+  }
+
+  /**
+   * Load configuration from a buffered reader
+   * @param reader Buffered reader to read the properties values from
+   * @return properties
+   * @throws IOException Exception thrown the file can't be read
+   */
+  public static Properties loadConfiguration(BufferedReader reader) throws IOException {
+    Properties config = new Properties();
+    config.load(reader);
+    return config;
+  }
+
+  /**
+   * Add configurations from one properties file to another
+   * @param to Properties file to copy values to
+   * @param from Properties file to copy values from
+   * @return a map containing the results of the values added
+   */
+  public static Map<String, String> addConfiguration(Properties to, Properties from) {
+    Map<String, String> results = from.entrySet()
+      .stream()
+      .filter(entry -> !to.containsKey(entry.getKey()))
+      .map(entry -> {
+        String key = entry.getKey().toString();
+        String value = entry.getValue().toString();
+        to.put(key, value);
+        return new Pair<String, String>(key, value);
+      })
+      .collect(Collectors.toMap(key -> key.getValue1(), value -> value.getValue2()));
+    
+    return results;
+  }
+  
+  /**
+   * Removes configuration values that are not present in the comparedTo
+   * @param from Properties file to remove values from
+   * @param comparedTo Properties file to compare to
+   * @return a map containing the results of the values removed
+   */
+  public static Map<String, String> removeConfiguration(Properties from, Properties comparedTo) {
+    Map<String, String> results = from.keySet()
+      .stream()
+      .filter(key -> !comparedTo.containsKey(key)) //only get the items that are not in the comparedTo properties
+      .map(key -> new Pair<String, String>(String.valueOf(key), String.valueOf(from.get(key))))
+      .collect(Collectors.toList()) //Create a list of paired items (key value) of the items that were filtered
+      .stream()
+      .map(pair -> { //remove those pairs from the from properties
+        from.remove(pair.getValue1());
+        return pair;
+      })
+      .collect(Collectors.toMap(key -> key.getValue1(), value -> value.getValue2())); //create a map of what was removed
+    
+    return results;
+  }
+
+  /**
+   * Save the properties file to disk
+   * @param props Properties file to save
+   * @param fileToSave File to save to
+   * @param comment Any comments to add
+   */
+  public static void saveConfiguration(Properties props, File fileToSave, String comment) {
+    try(FileOutputStream fos = new FileOutputStream(fileToSave)) {
+        props.store(fos, comment == null ? "" : comment);
+    } catch (IOException ex) {
+      throw new RuntimeException(ex.getMessage(), ex);
+    }
+  }
+}