Added ConfigWrapper to unify the logic for locating configuration data.

core/src/main/groovy/com/jdbernard/wdiwtlt/ConfigWrapper.groovy

@@ -0,0 +1,81 @@
+package com.jdbernard.wdiwtlt
+
+import com.zaxxer.hikari.HikariConfig
+
+public class ConfigWrapper {
+
+    Properties configProps
+    Map<String, String> env = System.getenv()
+
+    public ConfigWrapper() {
+        if (env.WDIWTLT_CONFIG_FILE) {
+            if (tryLoadConfigFile(new File(env.WDIWTLT_CONFIG_FILE))) {
+                return } }
+
+        if (tryLoadConfigFile(new File(env.HOME, ".wdiwtlt.properties"))) return
+
+        try {
+            ConfigWrapper.getResourceAsStream("/wdiwtlt.default.properties")
+                .withStream { tryLoadConfig(is) } }
+        catch (Exception e) {} }
+
+    public ConfigWrapper(File propertiesFile) {
+        this.configPropertiesFile = configPropertiesFile }
+
+    public String getLibraryRootPath() {
+        // 1. Check config properties
+        if (configProps && configProps["library.dir"])
+            return configProps["library.dir"]
+
+        // 2. Check environment variable 
+        if (env.WDIWTLT_LIBRARY_DIR)
+            return env.WDIWTLT_LIBRARY_DIR
+
+        return null }
+
+    public String getHikariConfig() {
+        Properties props = new Properties()
+
+        // 1. Check config properties for database config file
+        if (configProps) {
+
+            // 1.1 Look for a reference to a dedicated config file
+            if (configProps["database.config.file"]) {
+                File cf = new File(configProps["database.config.file"])
+                if (cf.exists() && cf.isFile())
+                    cf.withInputStream { props.load(it) } }
+
+            // 1.2 Look for prefixed properties in this config file
+            else if (configProps["database.config.dataSourceClassName"]) {
+                props.putAll(configProps
+                    .findAll { it.key.startsWith("database.config.") }
+                    .collectEntries { [it.key[16..-1], it.value] } ) } }
+
+        // 2. Look for environment variables
+        if (!props) {
+            if (env.WDIWTLT_DATASOURCE_CLASSNAME)
+                props["dataSourceClassName"] = env.WDIWTLT_DATABASE_DATASOURCECLASSNAME
+
+            if (env.WDIWTLT_DATASOURCE_PROPERTIES) {
+                props.putAll(env.WDIWTLT_DATASOURCE_PROPERTIES.split(":")
+                    .collect { it.split("=") }
+                    .collectEntries { ["dataSource.${it[0]}", it[1]] }) } }
+
+        // If properties exist, create and return HikariConfig
+        if (props) return new HikariConfig(props)
+        else return null }
+
+    private boolean tryLoadConfigFile(File configFile) {
+        if (!configFile.exists() || !configFile.isFile()) return false
+
+        return configFile.withInputStream { tryLoadConfig(is) } }
+
+    private boolean tryLoadConfig(InputStream is) {
+        try {
+            Properties props = new Properties()
+            props.load(is)
+            this.configProps = props }
+        catch (Exception e) { return false }
+
+        return true }
+}