Added pre processing feature for properties. Resolves #120

TODO.md

@@ -0,0 +1,7 @@
+TODO LIST
+=========
+
+Web site:
+- [ ] Write documentation for pre processing feature
+- [ ] Write documentation for JMX support
+- [ ] Update the release note.

owner/src/main/java/org/aeonbits/owner/Config.java

@@ -329,4 +329,17 @@ enum DisableableFeature {
         Class<? extends Converter> value();
     }
 
+    /**
+     * Specifies a <tt>{@link Preprocessor}</tt> class to allow the user to define a custom logic to pre-process
+     * the property value before being used by the library.
+     *
+     * @since 1.0.9
+     */
+    @Retention(RUNTIME)
+    @Target({METHOD, TYPE})
+    @Documented
+    @interface PreprocessorClasses {
+        Class<? extends Preprocessor>[] value();
+    }
+
 }

owner/src/main/java/org/aeonbits/owner/Preprocessor.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2012-2015, Luigi R. Viggiano
+ * All rights reserved.
+ *
+ * This software is distributable under the BSD license.
+ * See the terms of the BSD license in the documentation provided with this software.
+ */
+
+package org.aeonbits.owner;
+
+/**
+ * Preprocessor interface specifies how to pre-process an input string coming from a property value before being used by
+ * OWNER.
+ *
+ * @author Luigi R. Viggiano
+ * @since 1.0.9
+ */
+public interface Preprocessor {
+    String process(String input);
+}

owner/src/main/java/org/aeonbits/owner/PreprocessorResolver.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2012-2015, Luigi R. Viggiano
+ * All rights reserved.
+ *
+ * This software is distributable under the BSD license.
+ * See the terms of the BSD license in the documentation provided with this software.
+ */
+
+package org.aeonbits.owner;
+
+import org.aeonbits.owner.Config.PreprocessorClasses;
+
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+
+import static java.util.Collections.emptyList;
+import static org.aeonbits.owner.Util.newInstance;
+
+/**
+ * @author Luigi R. Viggiano
+ */
+final class PreprocessorResolver {
+
+    /** Don't let anyone instantiate this class */
+    private PreprocessorResolver() {}
+
+    public static List<Preprocessor> resolvePreprocessors(Method method) {
+        List<Preprocessor> result = new ArrayList<Preprocessor>();
+        List<Preprocessor> preprocessorsOnMethod = getPreprocessor(method.getAnnotation(PreprocessorClasses.class));
+        result.addAll(preprocessorsOnMethod);
+
+        List<Preprocessor> preprocessorsOnClass = getPreprocessor(method.getDeclaringClass().getAnnotation(PreprocessorClasses.class));
+        result.addAll(preprocessorsOnClass);
+
+        return result;
+    }
+
+    private static List<Preprocessor> getPreprocessor(PreprocessorClasses preprocessorClassesAnnotation) {
+        if (preprocessorClassesAnnotation == null) return emptyList();
+        Class<? extends Preprocessor>[] preprocessorClasses = preprocessorClassesAnnotation.value();
+        if (preprocessorClasses == null) return emptyList();
+        List<Preprocessor> result = new LinkedList<Preprocessor>();
+        return newInstance(preprocessorClassesAnnotation.value(), result);
+    }
+
+}

owner/src/main/java/org/aeonbits/owner/PropertiesInvocationHandler.java

@@ -18,6 +18,7 @@
 import static org.aeonbits.owner.Config.DisableableFeature.PARAMETER_FORMATTING;
 import static org.aeonbits.owner.Config.DisableableFeature.VARIABLE_EXPANSION;
 import static org.aeonbits.owner.Converters.convert;
+import static org.aeonbits.owner.PreprocessorResolver.resolvePreprocessors;
 import static org.aeonbits.owner.PropertiesMapper.key;
 import static org.aeonbits.owner.Util.isFeatureDisabled;
 import static org.aeonbits.owner.util.Reflection.invokeDefaultMethod;
@@ -79,11 +80,20 @@ private Object resolveProperty(Method method, Object... args) {
         }
         if (value == null)
             return null;
+        value = preProcess(method, value);
         Object result = convert(method, method.getReturnType(), format(method, expandVariables(method, value), args));
         if (result == Converters.NULL) return null;
         return result;
     }
 
+    private String preProcess(Method method, String value) {
+        List<Preprocessor> preprocessors = resolvePreprocessors(method);
+        String result = value;
+        for (Preprocessor preprocessor : preprocessors)
+            result = preprocessor.process(result);
+        return result;
+    }
+
     private String expandKey(Method method) {
         String key = key(method);
         if (isFeatureDisabled(method, VARIABLE_EXPANSION))

owner/src/main/java/org/aeonbits/owner/TokenizerResolver.java

@@ -13,6 +13,7 @@
 
 import java.lang.reflect.Method;
 
+import static org.aeonbits.owner.Util.newInstance;
 import static org.aeonbits.owner.Util.unsupported;
 
 /**
@@ -50,7 +51,7 @@ private static Tokenizer resolveTokenizerOnClassLevel(Class<?> declaringClass) {
             return new SplitAndTrimTokenizer(separatorAnnotationOnClassLevel.value());
 
         if (tokenizerClassAnnotationOnClassLevel != null)
-            return createTokenizer(tokenizerClassAnnotationOnClassLevel.value());
+            return newInstance(tokenizerClassAnnotationOnClassLevel.value());
 
         return null;
     }
@@ -68,19 +69,9 @@ private static Tokenizer resolveTokenizerOnMethodLevel(Method targetMethod) {
             return new SplitAndTrimTokenizer(separatorAnnotationOnMethodLevel.value());
 
         if (tokenizerClassAnnotationOnMethodLevel != null)
-            return createTokenizer(tokenizerClassAnnotationOnMethodLevel.value());
+            return newInstance(tokenizerClassAnnotationOnMethodLevel.value());
 
         return null;
     }
 
-    private static Tokenizer createTokenizer(Class<? extends Tokenizer> tokenizerClass) {
-        try {
-            return tokenizerClass.newInstance();
-        } catch (Exception e) {
-            throw unsupported(e,
-                    "Tokenizer class '%s' cannot be instantiated; see the cause below in the stack trace",
-                    tokenizerClass.getCanonicalName());
-        }
-    }
-
 }

owner/src/main/java/org/aeonbits/owner/Util.java

@@ -249,4 +249,19 @@ private static byte[] toBytes(Properties props) throws IOException {
         }
     }
 
+    public static <T> T newInstance(Class<T> clazz) {
+        try {
+            return clazz.newInstance();
+        } catch (Exception e) {
+            throw unsupported(e,
+                    "Class '%s' cannot be instantiated; see the cause below in the stack trace",
+                    clazz.getCanonicalName());
+        }
+    }
+
+    public static <T> List<T> newInstance(Class<? extends T>[] classes, List<T> result) {
+        for (Class<? extends T> clazz : classes)
+            result.add(newInstance(clazz));
+        return result;
+    }
 }

owner/src/test/java/org/aeonbits/owner/ConfigTest.java

@@ -29,7 +29,7 @@ public class ConfigTest {
     @Mock
     private ScheduledExecutorService scheduler;
 
-    public static interface SampleConfig extends Config {
+    public interface SampleConfig extends Config {
         String hello(String param);
 
         @DefaultValue("Bohemian Rapsody - Queen")

owner/src/test/java/org/aeonbits/owner/ConfigWithSubstitutionTest.java

@@ -17,7 +17,7 @@
  */
 public class ConfigWithSubstitutionTest {
 
-    public static interface ConfigWithSubstitutionFile extends Config {
+    public interface ConfigWithSubstitutionFile extends Config {
         String story();
     }
 

owner/src/test/java/org/aeonbits/owner/DisableFeatureTest.java

@@ -19,7 +19,7 @@
  * @author Luigi R. Viggiano
  */
 public class DisableFeatureTest {
-    public static interface ConfigWithSubstitutionDisabledOnMethod extends Config {
+    public interface ConfigWithSubstitutionDisabledOnMethod extends Config {
         @DefaultValue("Earth")
         String world();
 

owner/src/test/java/org/aeonbits/owner/PreprocessorTest.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2012-2015, Luigi R. Viggiano
+ * All rights reserved.
+ *
+ * This software is distributable under the BSD license.
+ * See the terms of the BSD license in the documentation provided with this software.
+ */
+
+package org.aeonbits.owner;
+
+import org.aeonbits.owner.Config.PreprocessorClasses;
+import org.junit.Test;
+
+import static java.lang.Math.max;
+import static java.lang.Math.min;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+/**
+ * Issue #120
+ *
+ * @author Luigi R. Viggiano
+ */
+public class PreprocessorTest {
+
+    @PreprocessorClasses({ SkipInlineComments.class, Trim.class })
+    public interface ConfigWithPreprocessors extends Config {
+        @DefaultValue("  300  ")
+        Integer pollingPeriod();
+
+        @PreprocessorClasses(ToLowerCase.class)
+        @DefaultValue("  HelloWorld  ")
+        String helloWorld();
+
+        @DefaultValue("  This is the value  ! this is an inline comment # this is the inline comment too")
+        String skipsInlineComments();
+
+        @PreprocessorClasses(ToLowerCase.class)
+        String nullValue();
+    }
+
+    @Test
+    public void shouldReturnTrimmedValue() {
+        ConfigWithPreprocessors cfg = ConfigFactory.create(ConfigWithPreprocessors.class);
+        assertEquals(new Integer(300), cfg.pollingPeriod());
+    }
+
+    @Test
+    public void shouldReturnLowercasedTrimmedHelloWorld() {
+        ConfigWithPreprocessors cfg = ConfigFactory.create(ConfigWithPreprocessors.class);
+        assertEquals("helloworld", cfg.helloWorld());
+    }
+
+    @Test
+    public void shouldSkipInlineComments() {
+        ConfigWithPreprocessors cfg = ConfigFactory.create(ConfigWithPreprocessors.class);
+        assertEquals("This is the value", cfg.skipsInlineComments());
+    }
+
+    @Test
+    public void shouldNotThrowExceptions() {
+        ConfigWithPreprocessors cfg = ConfigFactory.create(ConfigWithPreprocessors.class);
+        assertNull(cfg.nullValue());
+    }
+
+
+    // preprocessors implementation
+
+    public static class Trim implements Preprocessor {
+        public String process(String input) {
+            return input.trim();
+        }
+    }
+
+    public static class ToLowerCase implements Preprocessor {
+        public String process(String input) {
+            return input.toLowerCase();
+        }
+    }
+
+    public static class SkipInlineComments implements Preprocessor {
+        public String process(String input) {
+            int hashTagIndex = input.indexOf('#');
+            int exclamationMarkIndex = input.indexOf("!");
+            if (hashTagIndex == -1 && exclamationMarkIndex == -1)
+                return input; // comments not present.
+
+            int commentIndex = min(hashTagIndex, exclamationMarkIndex);
+            if (commentIndex == -1)
+                commentIndex = max(hashTagIndex, exclamationMarkIndex);
+
+            return input.substring(0, commentIndex);
+        }
+    }
+
+}

owner/src/test/java/org/aeonbits/owner/TestConstants.java

@@ -12,5 +12,5 @@
  * @author luigi
  */
 public interface TestConstants {
-    static final String RESOURCES_DIR = "target/test-generated-resources";
+    String RESOURCES_DIR = "target/test-generated-resources";
 }

owner/src/test/java/org/aeonbits/owner/UndefinedPropertiesTest.java

@@ -17,7 +17,7 @@
  */
 public class UndefinedPropertiesTest {
 
-    public static interface Person extends Config {
+    public interface Person extends Config {
         String name();
         int age();
         Double weight();

owner/src/test/java/org/aeonbits/owner/UtilTest.java

@@ -106,9 +106,9 @@ public static Map<String, String> getenv() {
         return Util.system().getenv();
     }
 
-    public static interface MyCloneable extends Cloneable {
+    public interface MyCloneable extends Cloneable {
         // for some stupid reason java.lang.Cloneable doesn't define this method...
-        public Object clone() throws CloneNotSupportedException;
+        Object clone() throws CloneNotSupportedException;
     }
 
     @SuppressWarnings("unchecked")