[ANCHOR-809][SEP-6] Add funding_method to SEP-6

api-schema/src/main/java/org/stellar/anchor/api/platform/GetTransactionResponse.java

@@ -12,4 +12,6 @@
  */
 @SuperBuilder
 @NoArgsConstructor
-public class GetTransactionResponse extends PlatformTransactionData {}
+public class GetTransactionResponse extends PlatformTransactionData {
+  String fundingMethod;
+}

api-schema/src/main/java/org/stellar/anchor/api/sep/sep6/InfoResponse.java

@@ -1,6 +1,7 @@
 package org.stellar.anchor.api.sep.sep6;
 
 import com.google.gson.annotations.SerializedName;
+import java.util.List;
 import java.util.Map;
 import lombok.Builder;
 import lombok.Data;
@@ -77,13 +78,16 @@ public static class DepositAssetResponse {
     @SerializedName("max_amount")
     Long maxAmount;
 
+    @SerializedName("funding_methods")
+    List<String> fundingMethods;
+
     /**
      * The fields required to initiate a deposit.
      *
      * <p>The only field supported by the platform is <code>type</code>. Additional fields required
      * for KYC are supplied asynchronously through SEP-12 requests.
      */
-    Map<String, AssetInfo.Field> fields;
+    @Deprecated Map<String, AssetInfo.Field> fields;
   }
 
   /** Withdrawal configuration. */
@@ -109,14 +113,18 @@ public static class WithdrawAssetResponse {
     @SerializedName("max_amount")
     Long maxAmount;
 
+    /** The maximum amount that can be withdrawn. */
+    @SerializedName("funding_methods")
+    List<String> fundingMethods;
+
     /**
      * The types of withdrawal methods supported and their fields.
      *
      * <p>The platform does not allow fields to be configured for withdrawal methods. Financial
      * account and KYC information is supplied asynchronously through PATCH requests and SEP-12
      * requests respectively.
      */
-    Map<String, WithdrawType> types;
+    @Deprecated Map<String, WithdrawType> types;
   }
 
   /** Withdrawal type configuration. */

api-schema/src/main/java/org/stellar/anchor/api/sep/sep6/StartDepositExchangeRequest.java

@@ -49,8 +49,12 @@ public class StartDepositExchangeRequest {
   /** The memo to use for the deposit. */
   String memo;
 
-  /** Type of deposit. */
-  @NonNull String type;
+  /** Deposit method used for the transaction. */
+  @SerializedName("funding_method")
+  String fundingMethod;
+
+  /** Type of deposit. Deprecated in favor of funding_method */
+  @Deprecated String type;
 
   /**
    * Defaults to en if not specified or if the specified language is not supported. Currently,

api-schema/src/main/java/org/stellar/anchor/api/sep/sep6/StartDepositRequest.java

@@ -32,8 +32,12 @@ public class StartDepositRequest {
   @SerializedName("email_address")
   String emailAddress;
 
-  /** Type of deposit. */
-  String type;
+  /** Deposit method used for the transaction. */
+  @SerializedName("funding_method")
+  String fundingMethod;
+
+  /** Type of deposit. Deprecated in favor of funding_method */
+  @Deprecated String type;
 
   /** Name of wallet to deposit to. Currently, ignored. */
   @SerializedName("wallet_name")

api-schema/src/main/java/org/stellar/anchor/api/sep/sep6/StartWithdrawExchangeRequest.java

@@ -39,8 +39,12 @@ public class StartWithdrawExchangeRequest {
   /** The amount of the source asset the user would like to withdraw. */
   @NonNull String amount;
 
-  /** The type of withdrawal to make. */
-  @NonNull String type;
+  /** Withdraw method used for the transaction. */
+  @SerializedName("funding_method")
+  String fundingMethod;
+
+  /** The type of withdrawal to make. Deprecated in favor of funding_method */
+  @Deprecated String type;
 
   /** The ISO 3166-1 alpha-3 code of the user's current address. */
   @SerializedName("country_code")

api-schema/src/main/java/org/stellar/anchor/api/sep/sep6/StartWithdrawRequest.java

@@ -20,8 +20,12 @@ public class StartWithdrawRequest {
   @NonNull
   String assetCode;
 
-  /** Type of withdrawal. */
-  String type;
+  /** Withdraw method used for the transaction. */
+  @SerializedName("funding_method")
+  String fundingMethod;
+
+  /** Type of withdrawal. Deprecated in favor of funding_method */
+  @Deprecated String type;
 
   /** The account to withdraw from. */
   String account;

core/src/main/java/org/stellar/anchor/sep6/RequestValidator.java

@@ -10,6 +10,7 @@
 import org.stellar.anchor.api.asset.StellarAssetInfo;
 import org.stellar.anchor.api.exception.*;
 import org.stellar.anchor.asset.AssetService;
+import org.stellar.anchor.util.StringHelper;
 import org.stellar.sdk.KeyPair;
 
 /** SEP-6 request validations */
@@ -91,6 +92,12 @@ public void validateAmount(
    */
   public void validateTypes(String requestType, String assetCode, List<String> validTypes)
       throws SepValidationException {
+    if (StringHelper.isEmpty(requestType)) {
+      throw new SepValidationException(
+          String.format(
+              "this field cannot be null or empty for asset %s, supported types are %s",
+              assetCode, validTypes));
+    }
     if (!validTypes.contains(requestType)) {
       throw new SepValidationException(
           String.format(

core/src/main/java/org/stellar/anchor/sep6/Sep6Service.java

@@ -107,10 +107,11 @@ public StartDepositResponse deposit(Sep10Jwt token, StartDepositRequest request)
     }
 
     StellarAssetInfo asset = requestValidator.getDepositAsset(request.getAssetCode());
-    if (request.getType() != null) {
-      requestValidator.validateTypes(
-          request.getType(), asset.getCode(), asset.getSep6().getDeposit().getMethods());
-    }
+    String fundingMethod =
+        request.getFundingMethod() != null ? request.getFundingMethod() : request.getType();
+    requestValidator.validateTypes(
+        fundingMethod, asset.getCode(), asset.getSep6().getDeposit().getMethods());
+
     if (request.getAmount() != null) {
       requestValidator.validateAmount(
           request.getAmount(),
@@ -130,7 +131,7 @@ public StartDepositResponse deposit(Sep10Jwt token, StartDepositRequest request)
             .transactionId(id)
             .status(SepTransactionStatus.INCOMPLETE.toString())
             .kind(Sep6Transaction.Kind.DEPOSIT.toString())
-            .type(request.getType())
+            .type(fundingMethod)
             .assetCode(request.getAssetCode())
             .assetIssuer(asset.getIssuer())
             .amountExpected(request.getAmount())
@@ -186,8 +187,10 @@ public StartDepositResponse depositExchange(Sep10Jwt token, StartDepositExchange
     }
 
     StellarAssetInfo buyAsset = requestValidator.getDepositAsset(request.getDestinationAsset());
+    String fundingMethod =
+        request.getFundingMethod() != null ? request.getFundingMethod() : request.getType();
     requestValidator.validateTypes(
-        request.getType(), buyAsset.getCode(), buyAsset.getSep6().getDeposit().getMethods());
+        fundingMethod, buyAsset.getCode(), buyAsset.getSep6().getDeposit().getMethods());
     requestValidator.validateAmount(
         request.getAmount(),
         buyAsset.getCode(),
@@ -224,7 +227,7 @@ public StartDepositResponse depositExchange(Sep10Jwt token, StartDepositExchange
             .transactionId(id)
             .status(SepTransactionStatus.INCOMPLETE.toString())
             .kind(Sep6Transaction.Kind.DEPOSIT_EXCHANGE.toString())
-            .type(request.getType())
+            .type(fundingMethod)
             .assetCode(buyAsset.getCode())
             .assetIssuer(buyAsset.getIssuer())
             .amountIn(amounts.getAmountIn())
@@ -281,10 +284,11 @@ public StartWithdrawResponse withdraw(Sep10Jwt token, StartWithdrawRequest reque
     }
 
     StellarAssetInfo asset = requestValidator.getWithdrawAsset(request.getAssetCode());
-    if (request.getType() != null) {
-      requestValidator.validateTypes(
-          request.getType(), asset.getCode(), asset.getSep6().getWithdraw().getMethods());
-    }
+    String fundingMethod =
+        request.getFundingMethod() != null ? request.getFundingMethod() : request.getType();
+    requestValidator.validateTypes(
+        fundingMethod, asset.getCode(), asset.getSep6().getWithdraw().getMethods());
+
     if (request.getAmount() != null) {
       requestValidator.validateAmount(
           request.getAmount(),
@@ -304,7 +308,7 @@ public StartWithdrawResponse withdraw(Sep10Jwt token, StartWithdrawRequest reque
             .transactionId(id)
             .status(SepTransactionStatus.INCOMPLETE.toString())
             .kind(Sep6Transaction.Kind.WITHDRAWAL.toString())
-            .type(request.getType())
+            .type(fundingMethod)
             .assetCode(request.getAssetCode())
             .assetIssuer(asset.getIssuer())
             .amountIn(request.getAmount())
@@ -357,8 +361,10 @@ public StartWithdrawResponse withdrawExchange(
     }
 
     StellarAssetInfo sellAsset = requestValidator.getWithdrawAsset(request.getSourceAsset());
+    String fundingMethod =
+        request.getFundingMethod() != null ? request.getFundingMethod() : request.getType();
     requestValidator.validateTypes(
-        request.getType(), sellAsset.getCode(), sellAsset.getSep6().getWithdraw().getMethods());
+        fundingMethod, sellAsset.getCode(), sellAsset.getSep6().getWithdraw().getMethods());
     requestValidator.validateAmount(
         request.getAmount(),
         sellAsset.getCode(),
@@ -395,7 +401,7 @@ public StartWithdrawResponse withdrawExchange(
             .transactionId(id)
             .status(SepTransactionStatus.INCOMPLETE.toString())
             .kind(Sep6Transaction.Kind.WITHDRAWAL_EXCHANGE.toString())
-            .type(request.getType())
+            .type(fundingMethod)
             .assetCode(sellAsset.getCode())
             .assetIssuer(sellAsset.getIssuer())
             .amountIn(amounts.getAmountIn())
@@ -534,6 +540,7 @@ private InfoResponse buildInfoResponse() {
             AssetInfo.Field.builder()
                 .description("type of deposit to make")
                 .choices(methods)
+                .optional(true)
                 .build();
 
         DepositAssetResponse deposit =
@@ -542,6 +549,7 @@ private InfoResponse buildInfoResponse() {
                 .authenticationRequired(true)
                 .minAmount(asset.getSep6().getDeposit().getMinAmount())
                 .maxAmount(asset.getSep6().getDeposit().getMaxAmount())
+                .fundingMethods(methods)
                 .fields(ImmutableMap.of("type", type))
                 .build();
 
@@ -555,13 +563,13 @@ private InfoResponse buildInfoResponse() {
         for (String method : methods) {
           types.put(method, WithdrawType.builder().fields(new HashMap<>()).build());
         }
-
         WithdrawAssetResponse withdraw =
             WithdrawAssetResponse.builder()
                 .enabled(true)
                 .authenticationRequired(true)
                 .minAmount(asset.getSep6().getWithdraw().getMinAmount())
                 .maxAmount(asset.getSep6().getWithdraw().getMaxAmount())
+                .fundingMethods(methods)
                 .types(types)
                 .build();
 

core/src/main/java/org/stellar/anchor/util/TransactionMapper.java

@@ -95,7 +95,7 @@ public static GetTransactionResponse toGetTransactionResponse(Sep31Transaction t
         .sep(PlatformTransactionData.Sep.SEP_31)
         .kind(RECEIVE)
         .status(SepTransactionStatus.from(txn.getStatus()))
-        .type(txn.getFundingMethod())
+        .fundingMethod(txn.getFundingMethod())
         .amountExpected(new Amount(txn.getAmountExpected(), txn.getAmountInAsset()))
         .amountIn(new Amount(txn.getAmountIn(), txn.getAmountInAsset()))
         .amountOut(new Amount(txn.getAmountOut(), txn.getAmountOutAsset()))
@@ -137,6 +137,7 @@ public static GetTransactionResponse toGetTransactionResponse(
         .sep(PlatformTransactionData.Sep.SEP_6)
         .kind(PlatformTransactionData.Kind.from(txn.getKind()))
         .status(SepTransactionStatus.from(txn.getStatus()))
+        .fundingMethod(txn.getType())
         .type(txn.getType())
         .amountExpected(
             (amountExpectedAsset != null)