feat: long support; safe delegation to int

src/main/java/dev/openfeature/sdk/Client.java

@@ -4,6 +4,9 @@
 
 /**
  * Interface used to resolve flags of varying types.
+ *
+ * <p><b>API note:</b> not intended for external implementation. Additive method changes
+ * (such as new flag-value-type accessors) are considered non-breaking.
  */
 public interface Client extends Features, Tracking, EventBus<Client> {
     ClientMetadata getMetadata();

src/main/java/dev/openfeature/sdk/FeatureProvider.java

@@ -9,49 +9,189 @@
  * should extend {@link EventProvider}
  */
 public interface FeatureProvider {
+
+    /** Maximum 64 bit integer losslessly representable as an IEEE-754 double: 2^53 - 1. */
+    long MAX_SAFE_INTEGER = 9_007_199_254_740_991L;
+
+    /**
+     * Returns provider-identifying metadata (typically the provider name).
+     *
+     * @return provider metadata
+     */
     Metadata getMetadata();
 
+    /**
+     * Returns provider-defined hooks that run alongside API/client/invocation hooks during
+     * flag evaluation. Provider hooks are managed by the provider, not the application author.
+     *
+     * @return list of provider hooks; empty by default
+     */
     default List<Hook> getProviderHooks() {
         return new ArrayList<>();
     }
 
+    /**
+     * Resolves a boolean flag value.
+     *
+     * @param key flag key
+     * @param defaultValue value to return in the {@link ProviderEvaluation} if resolution fails
+     * @param ctx merged evaluation context (may be empty, never {@code null})
+     * @return provider evaluation containing the resolved value or an error
+     */
     ProviderEvaluation<Boolean> getBooleanEvaluation(String key, Boolean defaultValue, EvaluationContext ctx);
 
+    /**
+     * Resolves a string flag value.
+     *
+     * @param key flag key
+     * @param defaultValue value to return in the {@link ProviderEvaluation} if resolution fails
+     * @param ctx merged evaluation context (may be empty, never {@code null})
+     * @return provider evaluation containing the resolved value or an error
+     */
     ProviderEvaluation<String> getStringEvaluation(String key, String defaultValue, EvaluationContext ctx);
 
+    /**
+     * Resolves a 32-bit integer flag value. For flags whose values may exceed
+     * {@link Integer#MAX_VALUE}, use {@link #getLongEvaluation} instead.
+     *
+     * @param key flag key
+     * @param defaultValue value to return in the {@link ProviderEvaluation} if resolution fails
+     * @param ctx merged evaluation context (may be empty, never {@code null})
+     * @return provider evaluation containing the resolved value or an error
+     */
     ProviderEvaluation<Integer> getIntegerEvaluation(String key, Integer defaultValue, EvaluationContext ctx);
 
+    /**
+     * Resolves a double-precision floating-point flag value.
+     *
+     * @param key flag key
+     * @param defaultValue value to return in the {@link ProviderEvaluation} if resolution fails
+     * @param ctx merged evaluation context (may be empty, never {@code null})
+     * @return provider evaluation containing the resolved value or an error
+     */
     ProviderEvaluation<Double> getDoubleEvaluation(String key, Double defaultValue, EvaluationContext ctx);
 
+    /**
+     * Resolves a 64-bit integer (Long) flag value.
+     *
+     * <p>The default implementation delegates to {@link #getDoubleEvaluation} and returns a
+     * {@link ProviderEvaluation} with {@link ErrorCode#TYPE_MISMATCH} for values outside the
+     * safe-integer range ({@code [-(2^53 - 1), 2^53 - 1]}) or non-integral doubles (NaN,
+     * +/-Infinity, fractional). Providers that natively support 64-bit integer flags should
+     * override this method.
+     *
+     * @param key flag key
+     * @param defaultValue value to return in the {@link ProviderEvaluation} if resolution fails
+     * @param ctx merged evaluation context (may be empty, never {@code null})
+     * @return provider evaluation containing the resolved value or an error
+     */
+    default ProviderEvaluation<Long> getLongEvaluation(String key, Long defaultValue, EvaluationContext ctx) {
+        if (defaultValue != null && !isWithinSafeRange(defaultValue)) {
+            return longError(
+                    defaultValue,
+                    "Default value " + defaultValue
+                            + " exceeds safe integer range [-(2^53 - 1), 2^53 - 1] for double-backed long evaluation");
+        }
+
+        Double doubleDefault = defaultValue == null ? null : (double) defaultValue;
+        ProviderEvaluation<Double> result = getDoubleEvaluation(key, doubleDefault, ctx);
+
+        Double boxed = result.getValue();
+        Long longValue;
+        if (boxed == null) {
+            longValue = defaultValue;
+        } else {
+            double value = boxed;
+            if (Double.isNaN(value) || Double.isInfinite(value)) {
+                return longError(defaultValue, "Cannot convert " + value + " to long", result);
+            }
+            if (value != Math.floor(value)) {
+                return longError(defaultValue, "Cannot convert fractional value " + value + " to long", result);
+            }
+            if (!isWithinSafeRange(value)) {
+                return longError(
+                        defaultValue,
+                        "Value " + value + " exceeds safe integer range [-(2^53 - 1), 2^53 - 1] for long",
+                        result);
+            }
+            longValue = (long) value;
+        }
+
+        return ProviderEvaluation.<Long>builder()
+                .value(longValue)
+                .reason(result.getReason())
+                .variant(result.getVariant())
+                .errorCode(result.getErrorCode())
+                .errorMessage(result.getErrorMessage())
+                .flagMetadata(result.getFlagMetadata())
+                .build();
+    }
+
+    // avoid Math.abs; Math.abs(Long.MIN_VALUE) == Long.MIN_VALUE (two's-complement overflow)
+    private static boolean isWithinSafeRange(long value) {
+        return value >= -MAX_SAFE_INTEGER && value <= MAX_SAFE_INTEGER;
+    }
+
+    private static boolean isWithinSafeRange(double value) {
+        return value >= -(double) MAX_SAFE_INTEGER && value <= (double) MAX_SAFE_INTEGER;
+    }
+
+    private static ProviderEvaluation<Long> longError(Long defaultValue, String message) {
+        return ProviderEvaluation.<Long>builder()
+                .value(defaultValue)
+                .reason(Reason.ERROR.toString())
+                .errorCode(ErrorCode.TYPE_MISMATCH)
+                .errorMessage(message)
+                .build();
+    }
+
+    // preserve upstream metadata/variant; override with type error
+    private static ProviderEvaluation<Long> longError(
+            Long defaultValue, String message, ProviderEvaluation<Double> upstream) {
+        return ProviderEvaluation.<Long>builder()
+                .value(defaultValue)
+                .reason(Reason.ERROR.toString())
+                .errorCode(ErrorCode.TYPE_MISMATCH)
+                .errorMessage(message)
+                .variant(upstream.getVariant())
+                .flagMetadata(upstream.getFlagMetadata())
+                .build();
+    }
+
+    /**
+     * Resolves a structured (object) flag value. Values are wrapped in {@link Value} which can
+     * carry booleans, strings, numbers, structures, and lists.
+     *
+     * @param key flag key
+     * @param defaultValue value to return in the {@link ProviderEvaluation} if resolution fails
+     * @param ctx merged evaluation context (may be empty, never {@code null})
+     * @return provider evaluation containing the resolved value or an error
+     */
     ProviderEvaluation<Value> getObjectEvaluation(String key, Value defaultValue, EvaluationContext ctx);
 
     /**
-     * This method is called before a provider is used to evaluate flags. Providers
-     * can overwrite this method,
-     * if they have special initialization needed prior being called for flag
-     * evaluation.
+     * Called once before a provider is used to evaluate flags. Providers can override this method
+     * if they have special initialization needed prior to being called for flag evaluation.
+     *
+     * <p>It is ok if the method is expensive; it is executed in the background. All runtime
+     * exceptions will be caught and logged.
      *
-     * <p>
-     * It is ok if the method is expensive as it is executed in the background. All
-     * runtime exceptions will be
-     * caught and logged.
-     * </p>
+     * @param evaluationContext the API-level evaluation context at the time of initialization
+     * @throws Exception any exception thrown here transitions the provider to
+     *     {@link ProviderState#ERROR} (or {@link ProviderState#FATAL} for
+     *     {@link dev.openfeature.sdk.exceptions.FatalError})
      */
     default void initialize(EvaluationContext evaluationContext) throws Exception {
         // Intentionally left blank
     }
 
     /**
-     * This method is called when a new provider is about to be used to evaluate
-     * flags, or the SDK is shut down.
-     * Providers can overwrite this method, if they have special shutdown actions
-     * needed.
+     * Called when a provider is about to be replaced or the SDK is shutting down. Providers can
+     * override this method if they have resources to release (background threads, connections,
+     * caches, etc.).
      *
-     * <p>
-     * It is ok if the method is expensive as it is executed in the background. All
-     * runtime exceptions will be
-     * caught and logged.
-     * </p>
+     * <p>It is ok if the method is expensive; it is executed in the background. All runtime
+     * exceptions will be caught and logged.
      */
     default void shutdown() {
         // Intentionally left blank

src/main/java/dev/openfeature/sdk/Features.java

@@ -2,6 +2,9 @@
 
 /**
  * An API for the type-specific fetch methods offered to users.
+ *
+ * <p><b>API note:</b> not intended for external implementation. Additive method changes
+ * (such as new flag-value-type accessors) are considered non-breaking.
  */
 public interface Features {
 
@@ -44,6 +47,19 @@ FlagEvaluationDetails<String> getStringDetails(
     FlagEvaluationDetails<Integer> getIntegerDetails(
             String key, Integer defaultValue, EvaluationContext ctx, FlagEvaluationOptions options);
 
+    Long getLongValue(String key, Long defaultValue);
+
+    Long getLongValue(String key, Long defaultValue, EvaluationContext ctx);
+
+    Long getLongValue(String key, Long defaultValue, EvaluationContext ctx, FlagEvaluationOptions options);
+
+    FlagEvaluationDetails<Long> getLongDetails(String key, Long defaultValue);
+
+    FlagEvaluationDetails<Long> getLongDetails(String key, Long defaultValue, EvaluationContext ctx);
+
+    FlagEvaluationDetails<Long> getLongDetails(
+            String key, Long defaultValue, EvaluationContext ctx, FlagEvaluationOptions options);
+
     Double getDoubleValue(String key, Double defaultValue);
 
     Double getDoubleValue(String key, Double defaultValue, EvaluationContext ctx);

src/main/java/dev/openfeature/sdk/FlagValueType.java

@@ -4,6 +4,7 @@
 public enum FlagValueType {
     STRING,
     INTEGER,
+    LONG,
     DOUBLE,
     OBJECT,
     BOOLEAN;

src/main/java/dev/openfeature/sdk/LongHook.java

@@ -0,0 +1,15 @@
+package dev.openfeature.sdk;
+
+/**
+ * An extension point which can run around flag resolution. They are intended to be used as a way to add custom logic
+ * to the lifecycle of flag evaluation.
+ *
+ * @see Hook
+ */
+public interface LongHook extends Hook<Long> {
+
+    @Override
+    default boolean supportsFlagValueType(FlagValueType flagValueType) {
+        return FlagValueType.LONG == flagValueType;
+    }
+}

src/main/java/dev/openfeature/sdk/OpenFeatureClient.java

@@ -302,6 +302,8 @@ private <T> ProviderEvaluation<?> createProviderEvaluation(
                 return provider.getStringEvaluation(key, (String) defaultValue, invocationContext);
             case INTEGER:
                 return provider.getIntegerEvaluation(key, (Integer) defaultValue, invocationContext);
+            case LONG:
+                return provider.getLongEvaluation(key, (Long) defaultValue, invocationContext);
             case DOUBLE:
                 return provider.getDoubleEvaluation(key, (Double) defaultValue, invocationContext);
             case OBJECT:
@@ -407,6 +409,37 @@ public FlagEvaluationDetails<Integer> getIntegerDetails(
         return this.evaluateFlag(FlagValueType.INTEGER, key, defaultValue, ctx, options);
     }
 
+    @Override
+    public Long getLongValue(String key, Long defaultValue) {
+        return getLongDetails(key, defaultValue).getValue();
+    }
+
+    @Override
+    public Long getLongValue(String key, Long defaultValue, EvaluationContext ctx) {
+        return getLongDetails(key, defaultValue, ctx).getValue();
+    }
+
+    @Override
+    public Long getLongValue(String key, Long defaultValue, EvaluationContext ctx, FlagEvaluationOptions options) {
+        return getLongDetails(key, defaultValue, ctx, options).getValue();
+    }
+
+    @Override
+    public FlagEvaluationDetails<Long> getLongDetails(String key, Long defaultValue) {
+        return getLongDetails(key, defaultValue, null);
+    }
+
+    @Override
+    public FlagEvaluationDetails<Long> getLongDetails(String key, Long defaultValue, EvaluationContext ctx) {
+        return getLongDetails(key, defaultValue, ctx, FlagEvaluationOptions.EMPTY);
+    }
+
+    @Override
+    public FlagEvaluationDetails<Long> getLongDetails(
+            String key, Long defaultValue, EvaluationContext ctx, FlagEvaluationOptions options) {
+        return this.evaluateFlag(FlagValueType.LONG, key, defaultValue, ctx, options);
+    }
+
     @Override
     public Double getDoubleValue(String key, Double defaultValue) {
         return getDoubleValue(key, defaultValue, null);

src/main/java/dev/openfeature/sdk/Value.java

@@ -70,6 +70,10 @@ public Value(Integer value) {
         this.innerObject = value;
     }
 
+    public Value(Long value) {
+        this.innerObject = value;
+    }
+
     public Value(Double value) {
         this.innerObject = value;
     }
@@ -213,6 +217,19 @@ public Integer asInteger() {
         return null;
     }
 
+    /**
+     * Retrieve the underlying numeric value as a Long, or null.
+     * If the value is a non-integral number, it will be truncated using Number#longValue().
+     *
+     * @return Long
+     */
+    public Long asLong() {
+        if (this.isNumber() && !this.isNull()) {
+            return ((Number) this.innerObject).longValue();
+        }
+        return null;
+    }
+
     /**
      * Retrieve the underlying numeric value as a Double, or null.
      *
@@ -301,6 +318,8 @@ public static Value objectToValue(Object object) {
             return new Value((Boolean) object);
         } else if (object instanceof Integer) {
             return new Value((Integer) object);
+        } else if (object instanceof Long) {
+            return new Value((Long) object);
         } else if (object instanceof Double) {
             return new Value((Double) object);
         } else if (object instanceof Structure) {