Add and use a Converter interface and implementations without using BeanUtils (apache#216)

* Fixes for CLI-321

Adds BeanUtils dependency to POM and implements TypeHandler using the BeanUtils classes.

Handles all methods that were in the original TypeHandler as well as other default classes provided by BeanUtils.
Test updated to show proper parsing of types that previously were not implemented.

Includes new cli.converters package that may be better handled by BeanUtils as it moves forward to support FunctionalInterfaces.

* Fixed issues with date parsing

* Switched to ConvertUtilsBean2 for conversions.

Added getParsedOptionValues methods with default values.
Fixed som javadoc,

* Implementation with tests

* fixed checkstyle issues

* fixed spotbugs error & some javadoc

* Updated spotbugs to 4.8.2.0

* added javadocs and  tests

* fixed breaking changes and javadoc

* added since annotation to Converter and Verifier

* Added an Enum Validator implementation

* fixed formatting issues

* fixed checkstyle error

* Converted Verifier to Predicate<String>

Verifier interface became static class to hold common Predicate<String> instances for verification.
Moved EnumVerifier into Verifier as a static method.

All references to Verifier as a data type chagned to Predicate<String>.

* Moved Converter, Verifier and their respective tests to base cli package.

* Removed verifier management and rebased to master

* moved param <T> tags

* updated numberic tests

* Updated documentation, added Supplier<String> as a default provider for getOptionValue

* fixed checkstyle issues

* Added Path to TypeHandler and updated documentation

* removed verifier

* removed verifier

* updated javadoc and site documentation

Author: Claudenw

pom.xml

@@ -192,6 +192,11 @@
       <artifactId>junit-vintage-engine</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-params</artifactId>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
   <properties>
@@ -246,6 +251,7 @@
         <configuration>
           <excludeFilterFile>${basedir}/src/conf/spotbugs-exclude-filter.xml</excludeFilterFile>
         </configuration>
+        <version>4.8.2.0</version>
       </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>

src/main/java/org/apache/commons/cli/CommandLine.java

@@ -25,6 +25,7 @@ Licensed to the Apache Software Foundation (ASF) under one or more
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Properties;
+import java.util.function.Supplier;
 
 /**
  * Represents list of arguments parsed against a {@link Options} descriptor.
@@ -254,6 +255,18 @@ public String getOptionValue(final char opt) {
      * @return Value of the argument if option is set, and has an argument, otherwise {@code defaultValue}.
      */
     public String getOptionValue(final char opt, final String defaultValue) {
+        return getOptionValue(String.valueOf(opt), () -> defaultValue);
+    }
+
+    /**
+     * Gets the argument, if any, of an option.
+     *
+     * @param opt character name of the option
+     * @param defaultValue is a supplier for the default value to be returned if the option is not specified.
+     * @return Value of the argument if option is set, and has an argument, otherwise {@code defaultValue}.
+     * @since 1.7.0
+     */
+    public String getOptionValue(final char opt, final Supplier<String> defaultValue) {
         return getOptionValue(String.valueOf(opt), defaultValue);
     }
 
@@ -281,10 +294,22 @@ public String getOptionValue(final Option option) {
      * @since 1.5.0
      */
     public String getOptionValue(final Option option, final String defaultValue) {
-        final String answer = getOptionValue(option);
-        return answer != null ? answer : defaultValue;
+        return getOptionValue(option, () -> defaultValue);
     }
 
+    /**
+     * Gets the first argument, if any, of an option.
+     *
+     * @param option name of the option.
+     * @param defaultValue is a supplier for the default value to be returned if the option is not specified.
+     * @return Value of the argument if option is set, and has an argument, otherwise {@code defaultValue}.
+     * @since 1.7.0
+     */
+    public String getOptionValue(final Option option, final Supplier<String> defaultValue) {
+        final String answer = getOptionValue(option);
+        return answer != null ? answer : defaultValue.get();
+    }
+    
     /**
      * Gets the first argument, if any, of this option.
      *
@@ -303,9 +328,22 @@ public String getOptionValue(final String opt) {
      * @return Value of the argument if option is set, and has an argument, otherwise {@code defaultValue}.
      */
     public String getOptionValue(final String opt, final String defaultValue) {
+        return getOptionValue(resolveOption(opt), () -> defaultValue);
+    }
+
+    /**
+     * Gets the first argument, if any, of an option.
+     *
+     * @param opt name of the option.
+     * @param defaultValue is a supplier for the default value to be returned if the option is not specified.
+     * @return Value of the argument if option is set, and has an argument, otherwise {@code defaultValue}.
+     * @since 1.7.0
+     */
+    public String getOptionValue(final String opt, final Supplier<String> defaultValue) {
         return getOptionValue(resolveOption(opt), defaultValue);
     }
 
+    
     /**
      * Gets the array of values, if any, of an option.
      *
@@ -349,46 +387,97 @@ public String[] getOptionValues(final String opt) {
      * Gets a version of this {@code Option} converted to a particular type.
      *
      * @param opt the name of the option.
+     * @param <T> The return type for the method.
      * @return the value parsed into a particular object.
      * @throws ParseException if there are problems turning the option value into the desired type
      * @see PatternOptionBuilder
      * @since 1.5.0
      */
-    public Object getParsedOptionValue(final char opt) throws ParseException {
+    public <T> T getParsedOptionValue(final char opt) throws ParseException {
         return getParsedOptionValue(String.valueOf(opt));
     }
 
     /**
      * Gets a version of this {@code Option} converted to a particular type.
      *
      * @param option the name of the option.
+     * @param <T> The return type for the method.
      * @return the value parsed into a particular object.
      * @throws ParseException if there are problems turning the option value into the desired type
      * @see PatternOptionBuilder
      * @since 1.5.0
      */
-    public Object getParsedOptionValue(final Option option) throws ParseException {
+    public <T> T getParsedOptionValue(final Option option) throws ParseException {
+        return  getParsedOptionValue(option, null);
+    }
+
+    /**
+     * Gets a version of this {@code Option} converted to a particular type.
+     *
+     * @param opt the name of the option.
+     * @param <T> The return type for the method.
+     * @return the value parsed into a particular object.
+     * @throws ParseException if there are problems turning the option value into the desired type
+     * @see PatternOptionBuilder
+     * @since 1.2
+     */
+    public <T> T getParsedOptionValue(final String opt) throws ParseException {
+        return getParsedOptionValue(resolveOption(opt));
+    }
+    
+    /**
+     * Gets a version of this {@code Option} converted to a particular type.
+     *
+     * @param opt the name of the option.
+     * @param defaultValue the default value to return if opt is not set.
+     * @param <T> The return type for the method.
+     * @return the value parsed into a particular object.
+     * @throws ParseException if there are problems turning the option value into the desired type
+     * @see PatternOptionBuilder
+     * @since 1.7.0
+     */
+    public <T> T getParsedOptionValue(final char opt, final T defaultValue) throws ParseException {
+        return getParsedOptionValue(String.valueOf(opt), defaultValue);
+    }
+
+    /**
+     * Gets a version of this {@code Option} converted to a particular type.
+     *
+     * @param option the name of the option.
+     * @param defaultValue the default value to return if opt is not set.
+     * @param <T> The return type for the method.
+     * @return the value parsed into a particular object.
+     * @throws ParseException if there are problems turning the option value into the desired type
+     * @see PatternOptionBuilder
+     * @since 1.7.0
+     */
+    @SuppressWarnings("unchecked")
+    public <T> T getParsedOptionValue(final Option option, final T defaultValue) throws ParseException {
         if (option == null) {
             return null;
         }
         final String res = getOptionValue(option);
-        if (res == null) {
-            return null;
+
+        try {
+            return res == null ? defaultValue : (T) option.getConverter().apply(res);
+        } catch (Exception e) {
+            throw ParseException.wrap(e);
         }
-        return TypeHandler.createValue(res, option.getType());
     }
 
     /**
      * Gets a version of this {@code Option} converted to a particular type.
      *
      * @param opt the name of the option.
+     * @param defaultValue the default value to return if opt is not set.
+     * @param <T> The return type for the method.
      * @return the value parsed into a particular object.
      * @throws ParseException if there are problems turning the option value into the desired type
      * @see PatternOptionBuilder
-     * @since 1.2
+     * @since 1.7.0
      */
-    public Object getParsedOptionValue(final String opt) throws ParseException {
-        return getParsedOptionValue(resolveOption(opt));
+    public <T> T getParsedOptionValue(final String opt, final T defaultValue) throws ParseException {
+        return getParsedOptionValue(resolveOption(opt), defaultValue);
     }
 
     /**

src/main/java/org/apache/commons/cli/Converter.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.cli;
+
+import java.io.File;
+import java.net.URL;
+import java.nio.file.Path;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+
+/**
+ * The definition of the functional interface to call when doing a conversion.
+ * Like {@code Function<String,T>} but can throw an Exception.
+ *
+ * @param <T> The return type for the function.
+ * @since 1.7.0
+ */
+@FunctionalInterface
+public interface Converter<T> {
+
+    /** The default converter. Does nothing. */
+    Converter<?> DEFAULT = s -> s;
+
+    /** Class name converter. Calls {@code Class.forName}. */
+    Converter<Class<?>> CLASS = s -> Class.forName(s);
+
+    /** File name converter. Calls @{code new File(s)} */
+    Converter<File> FILE = s -> new File(s);
+
+    /** Path converter. Calls @{code new Path(s)} */
+    Converter<Path> PATH = s -> new File(s).toPath();
+
+    /**
+     * Number converter. Converts to a Double if a decimal point ('.') is in the
+     * string or a Long otherwise.
+     */
+    Converter<Number> NUMBER = s -> {
+        if (s.indexOf('.') != -1) {
+            return Double.valueOf(s);
+        }
+        return Long.valueOf(s);
+    };
+
+    /**
+     * Converts a class name to an instance of the class. Uses the Class converter
+     * to find the class and then call the default constructor.
+     * @see #CLASS
+     */
+    Converter<Object> OBJECT = s -> CLASS.apply(s).getConstructor().newInstance();
+
+    /** Creates a URL. Calls {@code new URL(s)}. */
+    Converter<URL> URL = s -> new URL(s);
+
+    /** Converts to a date using the format string Form "EEE MMM dd HH:mm:ss zzz yyyy". */
+    Converter<Date> DATE = s -> new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy").parse(s);
+
+    /**
+     * Applies the conversion function to the String argument.
+     * @param  str       the String to convert
+     * @return           the Object from the conversion.
+     * @throws Exception on error.
+     */
+    T apply(String str) throws Exception;
+}

src/main/java/org/apache/commons/cli/Option.java

@@ -82,6 +82,9 @@ public static final class Builder {
 
         /** The character that is the value separator */
         private char valueSeparator;
+        
+        /** The converter to convert to type **/
+        private Converter<?> converter;
 
         /**
          * Constructs a new {@code Builder} with the minimum required parameters for an {@code Option} instance.
@@ -270,6 +273,19 @@ public Builder valueSeparator(final char valueSeparator) {
             this.valueSeparator = valueSeparator;
             return this;
         }
+
+        /**
+         * Sets the converter for the option.
+         * <p>Note: see {@link TypeHandler} for serialization discussion.</p>
+         * @param converter the Converter to use.
+         * @return this builder, to allow method chaining.
+         * @since 1.7.0
+         */
+        public Builder converter(final Converter<?> converter) {
+            this.converter = converter;
+            return this;
+        }
+        
     }
 
     /** Specifies the number of argument values has not been specified */
@@ -335,6 +351,9 @@ public static Builder builder(final String option) {
 
     /** The character that is the value separator. */
     private char valuesep;
+    
+    /** The explicit converter for this option.  May be null */
+    private transient Converter<?> converter;
 
     /**
      * Private constructor used by the nested Builder class.
@@ -351,6 +370,7 @@ private Option(final Builder builder) {
         this.required = builder.required;
         this.type = builder.type;
         this.valuesep = builder.valueSeparator;
+        this.converter = builder.converter;
     }
 
     /**
@@ -423,7 +443,6 @@ private void add(final String value) {
         if (!acceptsArg()) {
             throw new IllegalArgumentException("Cannot add value, list full.");
         }
-
         // store value
         values.add(value);
     }
@@ -695,6 +714,8 @@ private boolean hasNoValues() {
     }
 
     /**
+     * Returns whether this Option can have an optional argument.
+     * 
      * @return whether this Option can have an optional argument
      */
     public boolean hasOptionalArg() {
@@ -865,6 +886,24 @@ public void setType(final Object type) {
     public void setValueSeparator(final char sep) {
         this.valuesep = sep;
     }
+    
+    /**
+     * Gets the value to type converter.
+     * @return the value to type converter
+     * @since 1.7.0
+     */
+    public Converter<?> getConverter() {
+        return converter == null ? TypeHandler.getConverter(type) : converter;
+    }
+
+    /**
+     * Sets the value to type converter.
+     * @param converter The converter to convert the string value to the type.
+     * @since 1.7.0
+     */
+    public void setConverter(final Converter<?> converter) {
+        this.converter = converter;
+    }
 
     /**
      * Dump state, suitable for debugging.

src/main/java/org/apache/commons/cli/OptionBuilder.java

@@ -31,6 +31,7 @@ Licensed to the Apache Software Foundation (ASF) under one or more
 @Deprecated
 public final class OptionBuilder {
 
+
     /** Long option */
     private static String longOption;
 
@@ -108,6 +109,7 @@ public static Option create(final String opt) throws IllegalArgumentException {
             option.setOptionalArg(optionalArg);
             option.setArgs(argCount);
             option.setType(type);
+            option.setConverter(TypeHandler.getConverter(type));
             option.setValueSeparator(valueSeparator);
             option.setArgName(argName);
         } finally {