[COLLECTIONS-664] Add a class that extend a load method which accept …

src/main/java/org/apache/commons/collections4/properties/FileProperties.java

@@ -0,0 +1,42 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.collections4.properties;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Properties;
+
+/**
+ * A class that extend a load method which accept a filename.
+ * <p>
+ * Use context classloader to load current activated file.
+ * </p>
+ *
+ * @since 4.2
+ */
+public class FileProperties extends Properties {
+
+    private static final long serialVersionUID = 1L;
+
+    public synchronized Properties load(String fileName) throws IOException {
+        Properties properties = new Properties();
+        InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream(fileName);
+        properties.load(inputStream);
+        return properties;
+    }
+}

src/main/java/org/apache/commons/collections4/properties/package-info.java

@@ -21,6 +21,7 @@
  * The following classes are provided in the package:
  * <ul>
  *   <li>SortedProperties- A drop-in replacement for Properties for sorting keys.</li>
+ *   <li>FileProperties- A class that extend load functionality for getting Properties.<li/>
  * </ul>
  */
 package org.apache.commons.collections4.properties;

src/test/java/org/apache/commons/collections4/properties/FilePropertiesTest.java

@@ -0,0 +1,40 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.collections4.properties;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.util.Properties;
+
+public class FilePropertiesTest {
+
+    @Test
+    public void testLoad() {
+        final FileProperties fileProperties = new FileProperties();
+        try {
+            Properties properties = fileProperties.load("test.properties");
+            Assert.assertEquals(properties.get("test.key"), "age");
+            Assert.assertEquals(properties.get("test.group"), "human");
+            Assert.assertEquals(properties.get("test.value"), "28");
+        } catch (IOException iox) {
+            iox.printStackTrace();
+        }
+    }
+}

src/test/resources/test.properties

@@ -0,0 +1,3 @@
+test.key=age
+test.value=28
+test.group=human