feat(#159): Creates Arquillian SPI to resolve placeholders in configuration files

config/impl-base/pom.xml

@@ -35,6 +35,11 @@
       <artifactId>arquillian-config-api</artifactId>
       <version>${project.version}</version>
     </dependency>
+    <dependency>
+      <groupId>org.jboss.arquillian.config</groupId>
+      <artifactId>arquillian-config-spi</artifactId>
+      <version>${project.version}</version>
+    </dependency>
     <dependency>
       <groupId>org.jboss.arquillian.core</groupId>
       <artifactId>arquillian-core-api</artifactId>
@@ -51,7 +56,6 @@
       <artifactId>shrinkwrap-descriptors-spi</artifactId>
       <scope>compile</scope>
     </dependency>
-
     <dependency>
       <groupId>org.jboss.arquillian.core</groupId>
       <artifactId>arquillian-core-impl-base</artifactId>
@@ -65,12 +69,22 @@
       <version>${project.version}</version>
       <scope>test</scope>
     </dependency>
-
+    <dependency>
+      <groupId>org.jboss.arquillian.test</groupId>
+      <artifactId>arquillian-test-impl-base</artifactId>
+      <version>${project.version}</version>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-all</artifactId>
+      <scope>test</scope>
+    </dependency>
 
   </dependencies>
-</project>
+</project>

config/impl-base/src/main/java/org/jboss/arquillian/config/impl/extension/ClasspathConfigurationPlaceholderResolver.java

@@ -0,0 +1,20 @@
+package org.jboss.arquillian.config.impl.extension;
+
+import org.jboss.arquillian.config.descriptor.api.ArquillianDescriptor;
+import org.jboss.arquillian.config.spi.ConfigurationPlaceholderResolver;
+import org.jboss.shrinkwrap.descriptor.api.Descriptors;
+
+class ClasspathConfigurationPlaceholderResolver implements ConfigurationPlaceholderResolver {
+
+    public ArquillianDescriptor resolve(ArquillianDescriptor descriptor) {
+
+        final String descriptorAsString = descriptor.exportAsString();
+        return Descriptors.importAs(ArquillianDescriptor.class)
+            .fromString(StringPropertyReplacer.replaceClasspath(descriptorAsString));
+
+    }
+
+    public int precedence() {
+        return 0;
+    }
+}

config/impl-base/src/main/java/org/jboss/arquillian/config/impl/extension/ClasspathPropertyResolver.java

@@ -0,0 +1,33 @@
+package org.jboss.arquillian.config.impl.extension;
+
+import java.net.URL;
+import java.util.logging.Logger;
+
+class ClasspathPropertyResolver implements PropertyResolver {
+
+    private final static Logger logger = Logger.getLogger(ClasspathConfigurationPlaceholderResolver.class.getName());
+
+    /**
+     * Classpath base property
+     */
+    private static final String CLASSPATH = "classpath(";
+
+    public String getValue(String key) {
+
+        if (key.startsWith(CLASSPATH)) {
+            final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
+            String classpathResource = key.substring(CLASSPATH.length(), key.length() - 1);
+            final URL resource = contextClassLoader.getResource(classpathResource);
+
+            //If resource is not found it is returned as null so no change is applicable.
+            if (resource == null) {
+                logger.warning(String.format("Resource %s is not found on the classspath so the property %s is not replaced.", classpathResource, key));
+                return null;
+            }
+
+            return resource.toString();
+        }
+
+        return null;
+    }
+}

config/impl-base/src/main/java/org/jboss/arquillian/config/impl/extension/ConfigExtension.java

@@ -17,6 +17,7 @@
  */
 package org.jboss.arquillian.config.impl.extension;
 
+import org.jboss.arquillian.config.spi.ConfigurationPlaceholderResolver;
 import org.jboss.arquillian.core.spi.LoadableExtension;
 
 /**
@@ -29,5 +30,8 @@ public class ConfigExtension implements LoadableExtension {
     @Override
     public void register(ExtensionBuilder builder) {
         builder.observer(ConfigurationRegistrar.class);
+
+        builder.service(ConfigurationPlaceholderResolver.class, SystemPropertiesConfigurationPlaceholderResolver.class);
+        builder.service(ConfigurationPlaceholderResolver.class, ClasspathConfigurationPlaceholderResolver.class);
     }
 }

config/impl-base/src/main/java/org/jboss/arquillian/config/impl/extension/ConfigurationRegistrar.java

@@ -16,20 +16,26 @@
  */
 package org.jboss.arquillian.config.impl.extension;
 
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
 import org.jboss.arquillian.config.descriptor.api.ArquillianDescriptor;
+import org.jboss.arquillian.config.spi.ConfigurationPlaceholderResolver;
+import org.jboss.arquillian.core.api.Instance;
 import org.jboss.arquillian.core.api.InstanceProducer;
 import org.jboss.arquillian.core.api.annotation.ApplicationScoped;
 import org.jboss.arquillian.core.api.annotation.Inject;
 import org.jboss.arquillian.core.api.annotation.Observes;
 import org.jboss.arquillian.core.api.event.ManagerStarted;
+import org.jboss.arquillian.core.spi.ServiceLoader;
 import org.jboss.shrinkwrap.descriptor.api.Descriptors;
 
 import java.io.InputStream;
 import java.util.Map;
 import java.util.Properties;
 
-import static org.jboss.arquillian.config.impl.extension.ConfigurationSysPropResolver.resolveSystemProperties;
-
 /**
  * Configurator
  *
@@ -49,6 +55,9 @@ public class ConfigurationRegistrar {
     @ApplicationScoped
     private InstanceProducer<ArquillianDescriptor> descriptorInst;
 
+    @Inject
+    private Instance<ServiceLoader> serviceLoaderInstance;
+
     public void loadConfiguration(@Observes ManagerStarted event) {
         final InputStream input = FileUtils.loadArquillianXml(ARQUILLIAN_XML_PROPERTY, ARQUILLIAN_XML_DEFAULT);
 
@@ -67,11 +76,32 @@ public void loadConfiguration(@Observes ManagerStarted event) {
         propertiesParser.addProperties(descriptor, envProperties);
 
         //Placeholder resolver
-        final ArquillianDescriptor resolvedDesc = resolveSystemProperties(descriptor);
+        ArquillianDescriptor resolvedDesc = descriptor;
+
+        final List<ConfigurationPlaceholderResolver> configurationPlaceholderResolvers =
+            loadAndOrderPlaceholderResolvers();
+
+        for (ConfigurationPlaceholderResolver configurationPlaceholderResolver : configurationPlaceholderResolvers) {
+            resolvedDesc = configurationPlaceholderResolver.resolve(resolvedDesc);
+        }
 
         descriptorInst.set(resolvedDesc);
     }
 
+    private List<ConfigurationPlaceholderResolver> loadAndOrderPlaceholderResolvers() {
+        final List<ConfigurationPlaceholderResolver> configurationPlaceholderResolvers =
+            new ArrayList<ConfigurationPlaceholderResolver>(serviceLoaderInstance.get().all(ConfigurationPlaceholderResolver.class));
+
+        Collections.sort(configurationPlaceholderResolvers, new Comparator<ConfigurationPlaceholderResolver>() {
+            public int compare(ConfigurationPlaceholderResolver firstResolver, ConfigurationPlaceholderResolver secondResolver) {
+                Integer a = firstResolver.precedence();
+                Integer b = secondResolver.precedence();
+                return b.compareTo(a);
+            }
+        });
+        return configurationPlaceholderResolvers;
+    }
+
     private ArquillianDescriptor resolveDescriptor(final InputStream input) {
         final ArquillianDescriptor descriptor;
 

config/impl-base/src/main/java/org/jboss/arquillian/config/impl/extension/PropertiesPropertyResolver.java

@@ -0,0 +1,123 @@
+package org.jboss.arquillian.config.impl.extension;
+
+import java.io.File;
+import java.util.Properties;
+
+class PropertiesPropertyResolver implements PropertyResolver {
+    /**
+     * File separator value
+     */
+    private static final String FILE_SEPARATOR = File.separator;
+
+    /**
+     * Path separator value
+     */
+    private static final String PATH_SEPARATOR = File.pathSeparator;
+
+    /**
+     * File separator alias
+     */
+    private static final String FILE_SEPARATOR_ALIAS = "/";
+
+    /**
+     * Path separator alias
+     */
+    private static final String PATH_SEPARATOR_ALIAS = ":";
+
+
+    private final Properties props;
+
+    PropertiesPropertyResolver(Properties props) {
+        this.props = props;
+    }
+
+    public String getValue(String key) {
+
+        String value;
+
+        if (FILE_SEPARATOR_ALIAS.equals(key)) {
+            value = FILE_SEPARATOR;
+        } else if (PATH_SEPARATOR_ALIAS.equals(key)) {
+            value = PATH_SEPARATOR;
+        } else {
+            // check from the properties
+            if (props != null) {
+                value = props.getProperty(key);
+            } else {
+                value = System.getProperty(key);
+            }
+
+            if (value == null) {
+                // Check for a default value ${key:default}
+                int colon = key.indexOf(':');
+                if (colon > 0) {
+                    String realKey = key.substring(0, colon);
+                    if (props != null) {
+                        value = props.getProperty(realKey);
+                    } else {
+                        value = System.getProperty(realKey);
+                    }
+
+                    if (value == null) {
+                        // Check for a composite key, "key1,key2"
+                        value = resolveCompositeKey(realKey, props);
+
+                        // Not a composite key either, use the specified default
+                        if (value == null) {
+                            value = key.substring(colon + 1);
+                        }
+                    }
+                } else {
+                    // No default, check for a composite key, "key1,key2"
+                    value = resolveCompositeKey(key, props);
+                }
+            }
+        }
+
+        return value;
+    }
+
+    /**
+     * Try to resolve a "key" from the provided properties by
+     * checking if it is actually a "key1,key2", in which case
+     * try first "key1", then "key2". If all fails, return null.
+     * <p>
+     * It also accepts "key1," and ",key2".
+     *
+     * @param key
+     *     the key to resolve
+     * @param props
+     *     the properties to use
+     *
+     * @return the resolved key or null
+     */
+    private String resolveCompositeKey(String key, Properties props) {
+        String value = null;
+
+        // Look for the comma
+        int comma = key.indexOf(',');
+        if (comma > -1) {
+            // If we have a first part, try resolve it
+            if (comma > 0) {
+                // Check the first part
+                String key1 = key.substring(0, comma);
+                if (props != null) {
+                    value = props.getProperty(key1);
+                } else {
+                    value = System.getProperty(key1);
+                }
+            }
+            // Check the second part, if there is one and first lookup failed
+            if (value == null && comma < key.length() - 1) {
+                String key2 = key.substring(comma + 1);
+                if (props != null) {
+                    value = props.getProperty(key2);
+                } else {
+                    value = System.getProperty(key2);
+                }
+            }
+        }
+        // Return whatever we've found or null
+        return value;
+    }
+}

config/impl-base/src/main/java/org/jboss/arquillian/config/impl/extension/PropertyResolver.java

@@ -0,0 +1,5 @@
+package org.jboss.arquillian.config.impl.extension;
+
+interface PropertyResolver {
+    String getValue(String key);
+}