[IO-605] Add class CanExecuteFileFilter.

src/changes/changes.xml

@@ -92,6 +92,9 @@ The <action> type attribute can be add,update,fix,remove.
       <action issue="IO-604" dev="ggregory" type="fix" due-to="Gary Gregory">
         FileUtils.doCopyFile(File, File, boolean) can throw ClosedByInterruptException.
       </action>
+      <action issue="IO-605" dev="ggregory" type="add" due-to="Gary Gregory">
+        Add class CanExecuteFileFilter.
+      </action>
     </release>
 
     <release version="2.6" date="2017-10-15" description="Java 7 required, Java 9 supported.">

src/main/java/org/apache/commons/io/filefilter/CanExecuteFileFilter.java

@@ -0,0 +1,78 @@
+/*
+ * 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.io.filefilter;
+
+import java.io.File;
+import java.io.Serializable;
+
+/**
+ * This filter accepts <code>File</code>s that can be executed.
+ * <p>
+ * Example, showing how to print out a list of the
+ * current directory's <i>executable</i> files:
+ *
+ * <pre>
+ * File dir = new File(".");
+ * String[] files = dir.list( CanExecuteFileFilter.CAN_EXECUTE );
+ * for ( int i = 0; i &lt; files.length; i++ ) {
+ *     System.out.println(files[i]);
+ * }
+ * </pre>
+ *
+ * <p>
+ * Example, showing how to print out a list of the
+ * current directory's <i>un-executable</i> files:
+ *
+ * <pre>
+ * File dir = new File(".");
+ * String[] files = dir.list( CanExecuteFileFilter.CANNOT_EXECUTE );
+ * for ( int i = 0; i &lt; files.length; i++ ) {
+ *     System.out.println(files[i]);
+ * }
+ * </pre>
+ *
+ * @since 2.7
+ * @version $Id$
+ */
+public class CanExecuteFileFilter extends AbstractFileFilter implements Serializable {
+
+    private static final long serialVersionUID = 3179904805251622989L;
+
+    /** Singleton instance of <i>executable</i> filter */
+    public static final IOFileFilter CAN_EXECUTE = new CanExecuteFileFilter();
+
+    /** Singleton instance of not <i>executable</i> filter */
+    public static final IOFileFilter CANNOT_EXECUTE = new NotFileFilter(CAN_EXECUTE);
+
+    /**
+     * Restrictive constructor.
+     */
+    protected CanExecuteFileFilter() {
+    }
+
+    /**
+     * Checks to see if the file can be executed.
+     *
+     * @param file  the File to check.
+     * @return {@code true} if the file can be executed, otherwise {@code false}.
+     */
+    @Override
+    public boolean accept(final File file) {
+        return file.canExecute();
+    }
+
+}

src/test/java/org/apache/commons/io/filefilter/FileFilterTestCase.java

@@ -939,6 +939,22 @@ public void testHidden() throws Exception {
         assertFiltering(HiddenFileFilter.VISIBLE, getTestDirectory(), true);
     }
 
+    @Test
+    public void testCanExecute() throws Exception {
+        final File executableFile = File.createTempFile(getClass().getSimpleName(), ".temp");
+        try {
+            try (final BufferedOutputStream output = new BufferedOutputStream(new FileOutputStream(executableFile))) {
+                TestUtils.generateTestData(output, 32);
+            }
+            executableFile.setExecutable(true);
+            assertFiltering(CanExecuteFileFilter.CAN_EXECUTE, executableFile, true);
+            executableFile.setExecutable(false);
+            assertFiltering(CanExecuteFileFilter.CANNOT_EXECUTE, executableFile, false);
+        } finally {
+            executableFile.delete();
+        }
+    }
+
     @Test
     public void testCanRead() throws Exception {
         final File readOnlyFile = new File(getTestDirectory(), "read-only-file1.txt");