Refactor a bit to have fields declared the same way.

Renamed ConstructingObjectParser -> ObjectFactory (shorter name, felt more appropriate)

Fields (setters, etc) are now declared using a fluent interface on ObjectFactory and don't need to be done in a `static { ... }` block anymore

Also added back deprecated and obsolete fields.

Author: jordansissel

logstash-core/src/main/java/org/logstash/common/parser/DeprecatedField.java

@@ -0,0 +1,24 @@
+package org.logstash.common.parser;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.function.Function;
+
+public class DeprecatedField<Value> extends FieldDefinition<Value> {
+    private static final Logger logger = LogManager.getLogger();
+    private final String details;
+
+    DeprecatedField(String name, Function<Object, Value> transform, String details) {
+        super(name, transform);
+        this.details = details;
+    }
+
+    @Override
+    public Value apply(Object object) {
+        if (object != null) {
+            logger.warn("The field '" + getName() + "' is deprecated and will be removed soon: " + details);
+        }
+        return super.apply(object);
+    }
+}

logstash-core/src/main/java/org/logstash/common/parser/Field.java

@@ -5,12 +5,17 @@
 import java.util.function.Function;
 
 public interface Field<Value> extends Function<Object, Value> {
-    Field setDeprecated(String details);
+    static <V> Field<V> declareObject(String name, ObjectFactory<V> parser) {
+        return declareField(name, (config) -> parser.apply(ObjectTransforms.transformMap(config)));
+    }
+
+    String getName();
+
+    String getDetails();
 
     static Field<String> declareString(String name) {
         return declareField(name, ObjectTransforms::transformString);
     }
-    Field setObsolete(String details);
 
     static Field<Float> declareFloat(String name) {
         return declareField(name, ObjectTransforms::transformFloat);
@@ -36,8 +41,8 @@ static Field<Map<String, Object>> declareMap(String name) {
         return declareField(name, ObjectTransforms::transformMap);
     }
 
-    static <V> Field<V> declareObject(String name, ConstructingObjectParser<V> parser) {
-        return declareField(name, (config) -> parser.apply(ObjectTransforms.transformMap(config)));
+    default Value apply(Map<String, Object> map) {
+        return apply(map.get(getName()));
     }
 
     static <V> Field<List<V>> declareList(String name, Function<Object, V> transform) {
@@ -48,12 +53,4 @@ static <V> Field<V> declareField(String name, Function<Object, V> transform) {
         return new FieldDefinition<>(name, transform);
     }
 
-    String getName();
-
-    String getDetails();
-
-    default Value apply(Map<String, Object> map) {
-        return apply(map.get(getName()));
-    }
-
 }

logstash-core/src/main/java/org/logstash/common/parser/FieldDefinition.java

@@ -11,8 +11,7 @@ class FieldDefinition<Value> implements Field<Value> {
 
     private final String name;
 
-    // This is only set if deprecated or obsolete
-    // XXX: Move this concept separately to DeprecatedFieldDefinition and ObsoleteFieldDefinition
+    // XXX: Should Field definitions be separated in Field, DeprecatedField, ObsoleteField ?
     private FieldStatus status = FieldStatus.Supported;
     private String details;
 
@@ -21,43 +20,15 @@ class FieldDefinition<Value> implements Field<Value> {
         this.transform = transform;
     }
 
-    @Override
-    public Field setDeprecated(String details) {
-        setStatus(FieldStatus.Deprecated, details);
-        return this;
-    }
-
-    @Override
-    public Field setObsolete(String details) {
-        setStatus(FieldStatus.Obsolete, details);
-        return this;
-    }
-
-    private void setStatus(FieldStatus status, String details) {
-        this.status = status;
-        this.details = details;
-    }
-
     @Override
     public Value apply(Object object) {
         if (object == null) {
             throw new NullPointerException("The '" + name + "' field is required and no value was provided.");
         }
-        switch (status) {
-            // XXX: use Structured logging + localization lookups.
-            case Deprecated:
-                logger.warn("The field '" + getName() + "' is deprecated and will be removed soon: " + getDetails());
-                break;
-            case Obsolete:
-                logger.fatal("The field '" + getName() + "' is obsolete and has been removed: " + getDetails());
-                break;
-            case Supported:
-                break;
-        }
-
         return transform.apply(object);
     }
 
+    @Override
     public String getName() {
         return name;
     }

logstash-core/src/main/java/org/logstash/common/parser/FieldUsage.java

@@ -1,31 +1,31 @@
 package org.logstash.common.parser;
 
 class Functions {
-    public interface Function3<Arg0, Arg1, Arg2, Value> {
+    interface Function3<Arg0, Arg1, Arg2, Value> {
         Value apply(Arg0 arg0, Arg1 arg1, Arg2 arg2);
     }
 
-    public interface Function4<Arg0, Arg1, Arg2, Arg3, Value> {
+    interface Function4<Arg0, Arg1, Arg2, Arg3, Value> {
         Value apply(Arg0 arg0, Arg1 arg1, Arg2 arg2, Arg3 arg3);
     }
 
-    public interface Function5<Arg0, Arg1, Arg2, Arg3, Arg4, Value> {
+    interface Function5<Arg0, Arg1, Arg2, Arg3, Arg4, Value> {
         Value apply(Arg0 arg0, Arg1 arg1, Arg2 arg2, Arg3 arg3, Arg4 arg4);
     }
 
-    public interface Function6<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Value> {
+    interface Function6<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Value> {
         Value apply(Arg0 arg0, Arg1 arg1, Arg2 arg2, Arg3 arg3, Arg4 arg4, Arg5 arg5);
     }
 
-    public interface Function7<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Value> {
+    interface Function7<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Value> {
         Value apply(Arg0 arg0, Arg1 arg1, Arg2 arg2, Arg3 arg3, Arg4 arg4, Arg5 arg5, Arg6 arg6);
     }
 
-    public interface Function8<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Value> {
+    interface Function8<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Value> {
         Value apply(Arg0 arg0, Arg1 arg1, Arg2 arg2, Arg3 arg3, Arg4 arg4, Arg5 arg5, Arg6 arg6, Arg7 arg7);
     }
 
-    public interface Function9<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, Value> {
+    interface Function9<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, Value> {
         Value apply(Arg0 arg0, Arg1 arg1, Arg2 arg2, Arg3 arg3, Arg4 arg4, Arg5 arg5, Arg6 arg6, Arg7 arg7, Arg8 arg8);
     }
 }

logstash-core/src/main/java/org/logstash/common/parser/Functions.java

@@ -27,16 +27,18 @@
  *
  * @param <Value> The object type to construct when `parse` is called.
  */
-public class ConstructingObjectParser<Value> implements ObjectParser<Value> {
+public class ObjectFactory<Value> implements Function<Map<String, Object>, Value> {
     private final Map<String, BiConsumer<Value, Object>> parsers = new HashMap<>();
-    private List<Field<?>> constructorFields = null;
+    private List<Field<?>> constructorFields;
     private final Function<Map<String, Object>, Value> builder;
+
     /**
      * Zero-argument object constructor (A Supplier)
+     *
      * @param supplier The supplier which produces an object instance.
      */
     @SuppressWarnings("WeakerAccess") // Public Interface
-    public ConstructingObjectParser(Supplier<Value> supplier) {
+    public ObjectFactory(Supplier<Value> supplier) {
         this(config -> supplier.get());
         constructorFields = Collections.emptyList();
     }
@@ -45,7 +47,7 @@ public ConstructingObjectParser(Supplier<Value> supplier) {
      * One-argument object constructor
      */
     @SuppressWarnings("WeakerAccess") // Public Interface
-    public <Arg0> ConstructingObjectParser(Function<Arg0, Value> function, Field<Arg0> arg0) {
+    public <Arg0> ObjectFactory(Function<Arg0, Value> function, Field<Arg0> arg0) {
         this(config -> function.apply(arg0.apply(config)));
         constructorFields = Collections.singletonList(arg0);
     }
@@ -54,7 +56,7 @@ public <Arg0> ConstructingObjectParser(Function<Arg0, Value> function, Field<Arg
      * Two-argument object constructor
      */
     @SuppressWarnings("WeakerAccess") // Public Interface
-    public <Arg0, Arg1> ConstructingObjectParser(BiFunction<Arg0, Arg1, Value> function, Field<Arg0> arg0, Field<Arg1> arg1) {
+    public <Arg0, Arg1> ObjectFactory(BiFunction<Arg0, Arg1, Value> function, Field<Arg0> arg0, Field<Arg1> arg1) {
         this(config -> function.apply(arg0.apply(config), arg1.apply(config)));
         constructorFields = Arrays.asList(arg0, arg1);
     }
@@ -63,110 +65,55 @@ public <Arg0, Arg1> ConstructingObjectParser(BiFunction<Arg0, Arg1, Value> funct
      * Three-argument object constructor
      */
     @SuppressWarnings("WeakerAccess") // Public Interface
-    public <Arg0, Arg1, Arg2> ConstructingObjectParser(Function3<Arg0, Arg1, Arg2, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2) {
+    public <Arg0, Arg1, Arg2> ObjectFactory(Function3<Arg0, Arg1, Arg2, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2) {
         this(config -> function.apply(arg0.apply(config), arg1.apply(config), arg2.apply(config)));
         constructorFields = Arrays.asList(arg0, arg1, arg2);
     }
 
 
     @SuppressWarnings("WeakerAccess") // Public Interface
-    public <Arg0, Arg1, Arg2, Arg3> ConstructingObjectParser(Function4<Arg0, Arg1, Arg2, Arg3, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2, Field<Arg3> arg3) {
+    public <Arg0, Arg1, Arg2, Arg3> ObjectFactory(Function4<Arg0, Arg1, Arg2, Arg3, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2, Field<Arg3> arg3) {
         this(config -> function.apply(arg0.apply(config), arg1.apply(config), arg2.apply(config), arg3.apply(config)));
         constructorFields = Arrays.asList(arg0, arg1, arg2, arg3);
     }
 
     @SuppressWarnings("WeakerAccess") // Public Interface
-    public <Arg0, Arg1, Arg2, Arg3, Arg4> ConstructingObjectParser(Function5<Arg0, Arg1, Arg2, Arg3, Arg4, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2, Field<Arg3> arg3, Field<Arg4> arg4) {
+    public <Arg0, Arg1, Arg2, Arg3, Arg4> ObjectFactory(Function5<Arg0, Arg1, Arg2, Arg3, Arg4, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2, Field<Arg3> arg3, Field<Arg4> arg4) {
         this(config -> function.apply(arg0.apply(config), arg1.apply(config), arg2.apply(config), arg3.apply(config), arg4.apply(config)));
         constructorFields = Arrays.asList(arg0, arg1, arg2, arg3, arg4);
     }
 
     @SuppressWarnings("WeakerAccess") // Public Interface
-    public <Arg0, Arg1, Arg2, Arg3, Arg4, Arg5> ConstructingObjectParser(Function6<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2, Field<Arg3> arg3, Field<Arg4> arg4, Field<Arg5> arg5) {
+    public <Arg0, Arg1, Arg2, Arg3, Arg4, Arg5> ObjectFactory(Function6<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2, Field<Arg3> arg3, Field<Arg4> arg4, Field<Arg5> arg5) {
         this(config -> function.apply(arg0.apply(config), arg1.apply(config), arg2.apply(config), arg3.apply(config), arg4.apply(config), arg5.apply(config)));
         constructorFields = Arrays.asList(arg0, arg1, arg2, arg3, arg4, arg5);
     }
 
     @SuppressWarnings("WeakerAccess") // Public Interface
-    public <Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6> ConstructingObjectParser(Function7<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2, Field<Arg3> arg3, Field<Arg4> arg4, Field<Arg5> arg5, Field<Arg6> arg6) {
+    public <Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6> ObjectFactory(Function7<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2, Field<Arg3> arg3, Field<Arg4> arg4, Field<Arg5> arg5, Field<Arg6> arg6) {
         this(config -> function.apply(arg0.apply(config), arg1.apply(config), arg2.apply(config), arg3.apply(config), arg4.apply(config), arg5.apply(config), arg6.apply(config)));
         constructorFields = Arrays.asList(arg0, arg1, arg2, arg3, arg4, arg5, arg6);
     }
 
     @SuppressWarnings("WeakerAccess") // Public Interface
-    public <Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7> ConstructingObjectParser(Function8<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2, Field<Arg3> arg3, Field<Arg4> arg4, Field<Arg5> arg5, Field<Arg6> arg6, Field<Arg7> arg7) {
+    public <Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7> ObjectFactory(Function8<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2, Field<Arg3> arg3, Field<Arg4> arg4, Field<Arg5> arg5, Field<Arg6> arg6, Field<Arg7> arg7) {
         this(config -> function.apply(arg0.apply(config), arg1.apply(config), arg2.apply(config), arg3.apply(config), arg4.apply(config), arg5.apply(config), arg6.apply(config), arg7.apply(config)));
         constructorFields = Arrays.asList(arg0, arg1, arg2, arg3, arg4, arg5, arg6, arg7);
     }
 
     @SuppressWarnings("WeakerAccess") // Public Interface
-    public <Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8> ConstructingObjectParser(Function9<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2, Field<Arg3> arg3, Field<Arg4> arg4, Field<Arg5> arg5, Field<Arg6> arg6, Field<Arg7> arg7, Field<Arg8> arg8) {
+    public <Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8> ObjectFactory(Function9<Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, Value> function, Field<Arg0> arg0, Field<Arg1> arg1, Field<Arg2> arg2, Field<Arg3> arg3, Field<Arg4> arg4, Field<Arg5> arg5, Field<Arg6> arg6, Field<Arg7> arg7, Field<Arg8> arg8) {
         this(config -> function.apply(arg0.apply(config), arg1.apply(config), arg2.apply(config), arg3.apply(config), arg4.apply(config), arg5.apply(config), arg6.apply(config), arg7.apply(config), arg8.apply(config)));
         constructorFields = Arrays.asList(arg0, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
     }
 
-    private ConstructingObjectParser(Function<Map<String, Object>, Value> builder) {
+    private ObjectFactory(Function<Map<String, Object>, Value> builder) {
         this.builder = builder;
     }
 
-    private static <Value> Value construct(Map<String, Object> config, Function<Object[], Value> builder, Field<?>... constructorFields) throws IllegalArgumentException {
-        Object[] builderArgs = new Object[constructorFields.length];
-        int i = 0;
-        for (Field<?> field : constructorFields) {
-            final String name = field.getName();
-
-            if (config.containsKey(name)) {
-                builderArgs[i] = field.apply(config.get(name));
-            } else {
-                throw new IllegalArgumentException("Missing required argument '" + name + "'");
-            }
-
-            i++;
-        }
-
-        return builder.apply(builderArgs);
-    }
-
-    /**
-     * Declare a field. Field ordering does not matter.
-     * <p>
-     * A field is intended to call a Setter on an Object.
-     * <p>
-     * When calling `apply`, all fields are considered optional and may be absent from the config map.
-     * <p>
-     * <code>{@code
-     * ConstructingObjectParser<SocketServer> c = new ConstructingObjectParser<>(SocketServer::new)
-     * c.declareBoolean("reuseAddress", SocketServer::setReuseAddress);
-     * c.declareInteger("receiveBufferSize", SocketServer::setReceiveBufferSize);
-     * <p>
-     * Map<String, Object> config = new HashMap<>();
-     * config.put("reuseAddress", true);
-     * config.put("receiveBufferSize", 65536);
-     * SocketServer server = c.apply(config);
-     * }</code>
-     *
-     * @param name
-     * @param consumer
-     * @param transform
-     * @param <T>
-     * @return
-     */
-    @Override
-    @SuppressWarnings("WeakerAccess") // Public Interface
-    public <T> Field declareField(String name, BiConsumer<Value, T> consumer, Function<Object, T> transform) {
-        if (isKnownField(name)) {
-            throw new IllegalArgumentException("Duplicate field defined '" + name + "'");
-        }
-
-        BiConsumer<Value, Object> objConsumer = (value, object) -> consumer.accept(value, transform.apply(object));
-        FieldDefinition<T> field = new FieldDefinition<>(name, transform);
-        parsers.put(name, (value, input) -> consumer.accept(value, transform.apply(input)));
-        return field;
-    }
-
     /**
      * Use the given config to produce the Value object.
-     *
+     * <p>
      * Contract:
      * 1) All declared constructor arguments are required. If any are missing, an IllegalArgumentException is thrown.
      * 2) All declared fields are optional.
@@ -176,6 +123,7 @@ public <T> Field declareField(String name, BiConsumer<Value, T> consumer, Functi
      * @param config the configuration
      * @return the configured object
      */
+    @SuppressWarnings("WeakerAccess") // Public Interface
     public Value apply(Map<String, Object> config) {
         rejectUnknownFields(config.keySet());
 
@@ -219,4 +167,23 @@ private void rejectUnknownFields(Set<String> configNames) throws IllegalArgument
         }
     }
 
+    @SuppressWarnings("WeakerAccess") // Public Interface
+    public <T> ObjectFactory<Value> define(Field<T> field, BiConsumer<Value, T> consumer) {
+        if (isKnownField(field.getName())) {
+            throw new IllegalArgumentException("Duplicate field defined '" + field.getName() + "'");
+        }
+
+        parsers.put(field.getName(), (value, input) -> consumer.accept(value, field.apply(input)));
+        return this;
+    }
+
+    @SuppressWarnings("WeakerAccess") // Public Interface
+    public <T> ObjectFactory<Value> deprecate(Field<T> field, BiConsumer<Value, T> consumer, String details) {
+        return define(new DeprecatedField<>(field.getName(), field, details), consumer);
+    }
+
+    @SuppressWarnings("WeakerAccess") // Public Interface
+    public <T> ObjectFactory<Value> obsolete(Field<T> field, BiConsumer<Value, T> consumer, String details) {
+        return define(new ObsoleteField<>(field.getName(), field, details), consumer);
+    }
 }