Implement equals and hashCode in models

**Summary**
Implement `equals()` and `hashCode()` for all models,
specifically the subclasses of `StripeJsonModel`

**Motivation**
The implementation of `equals()`, `hashCode()`, and
`toString()` in `StripeJsonModel`, which is the base
class of almost all model classes, is extremely
inefficient. It implements these methods by first
transforming the model object to a JSON string, which
is an expensive operation.

**Testing**
- Updated unit tests
- Tested on device with example app

example/src/main/java/com/stripe/example/activity/PaymentIntentActivity.java

@@ -238,7 +238,7 @@ public void call() {
                             @Override
                             public void call(PaymentIntent paymentIntent) {
                                 if (paymentIntent != null) {
-                                    mPaymentIntentValue.setText(paymentIntent.toString());
+                                    mPaymentIntentValue.setText(paymentIntent.toJson().toString());
                                     Uri authUrl = paymentIntent.getAuthorizationUrl();
                                     if ("requires_source_action".equals(paymentIntent.getStatus())
                                             && authUrl != null) {

example/src/main/java/com/stripe/example/activity/PaymentSessionActivity.java

@@ -210,7 +210,7 @@ private String formatStringResults(PaymentSessionData data) {
                             .append(" ending in ")
                             .append(scd.getLast4());
                 } else {
-                    stringBuilder.append('\n').append(source.toString()).append('\n');
+                    stringBuilder.append('\n').append(source.toJson().toString()).append('\n');
                 }
                 String isOrNot = data.isPaymentReadyToCharge() ? " IS " : " IS NOT ";
                 stringBuilder.append(isOrNot).append("ready to charge.\n\n");

stripe/src/main/java/com/stripe/android/AbstractEphemeralKey.java

@@ -5,15 +5,16 @@
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
-import androidx.annotation.VisibleForTesting;
 
 import com.stripe.android.model.StripeJsonModel;
+import com.stripe.android.utils.ObjectUtils;
 
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
 import java.lang.reflect.InvocationTargetException;
+import java.util.AbstractMap;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -33,14 +34,15 @@ abstract class AbstractEphemeralKey extends StripeJsonModel implements Parcelabl
     static final String FIELD_ASSOCIATED_OBJECTS = "associated_objects";
     static final String FIELD_TYPE = "type";
     static final String NULL = "null";
-    protected @NonNull String mObjectId;
-    private long mCreated;
-    private long mExpires;
-    private @NonNull String mId;
-    private boolean mLiveMode;
-    private @NonNull String mObject;
-    private @NonNull String mSecret;
-    private @NonNull String mType;
+
+    @NonNull final String mObjectId;
+    private final long mCreated;
+    private final long mExpires;
+    @NonNull private final String mId;
+    private final boolean mLiveMode;
+    @NonNull private final String mObject;
+    @NonNull private final String mSecret;
+    @NonNull private final String mType;
 
     /**
      * Parcel constructor for this {@link Parcelable} class.
@@ -50,7 +52,7 @@ abstract class AbstractEphemeralKey extends StripeJsonModel implements Parcelabl
      *
      * @param in the {@link Parcel} in which this Ephemeral Key has been stored.
      */
-    protected AbstractEphemeralKey(Parcel in) {
+    AbstractEphemeralKey(@NonNull Parcel in) {
         mCreated = in.readLong();
         mObjectId = in.readString();
         mExpires = in.readLong();
@@ -61,7 +63,7 @@ protected AbstractEphemeralKey(Parcel in) {
         mType = in.readString();
     }
 
-    protected AbstractEphemeralKey(
+    AbstractEphemeralKey(
             long created,
             @NonNull String objectId,
             long expires,
@@ -81,9 +83,7 @@ protected AbstractEphemeralKey(
         mType = type;
     }
 
-    protected AbstractEphemeralKey(
-            @Nullable JSONObject jsonObject
-    ) throws JSONException {
+    AbstractEphemeralKey(@Nullable JSONObject jsonObject) throws JSONException {
         mCreated = jsonObject.getLong(FIELD_CREATED);
         mExpires = jsonObject.getLong(FIELD_EXPIRES);
         mId = jsonObject.getString(FIELD_ID);
@@ -129,18 +129,17 @@ public JSONObject toJson() {
 
     @NonNull
     @Override
-    @SuppressWarnings("unchecked")
     public Map<String, Object> toMap() {
-        Map map = new HashMap<>();
+        final AbstractMap<String, Object> map = new HashMap<>();
         map.put(FIELD_CREATED, mCreated);
         map.put(FIELD_EXPIRES, mExpires);
         map.put(FIELD_OBJECT, mObject);
         map.put(FIELD_ID, mId);
         map.put(FIELD_SECRET, mSecret);
         map.put(FIELD_LIVEMODE, mLiveMode);
 
-        List<Object> associatedObjectsList = new ArrayList<>();
-        Map<String, String> associatedObjectMap = new HashMap<>();
+        final List<Object> associatedObjectsList = new ArrayList<>();
+        final Map<String, String> associatedObjectMap = new HashMap<>();
         associatedObjectMap.put(FIELD_ID, mObjectId);
         associatedObjectMap.put(FIELD_TYPE, mType);
         associatedObjectsList.add(associatedObjectMap);
@@ -183,11 +182,6 @@ long getExpires() {
         return mExpires;
     }
 
-    @VisibleForTesting
-    void setExpires(long value) {
-        mExpires = value;
-    }
-
     @NonNull
     String getId() {
         return mId;
@@ -223,7 +217,7 @@ String getType() {
         return fromJson(object, ephemeralKeyClass);
     }
 
-    @Nullable
+    @NonNull
     protected static <TEphemeralKey extends AbstractEphemeralKey> TEphemeralKey
     fromJson(@Nullable JSONObject jsonObject, Class ephemeralKeyClass) {
         if (jsonObject == null) {
@@ -256,4 +250,27 @@ String getType() {
                     " does not have an accessible (JSONObject) constructor", e);
         }
     }
+
+    @Override
+    public boolean equals(@Nullable Object obj) {
+        return this == obj
+                || (obj instanceof AbstractEphemeralKey && typedEquals((AbstractEphemeralKey) obj));
+    }
+
+    private boolean typedEquals(@NonNull AbstractEphemeralKey ephemeralKey) {
+        return ObjectUtils.equals(mObjectId, ephemeralKey.mObjectId)
+                && mCreated == ephemeralKey.mCreated
+                && mExpires == ephemeralKey.mExpires
+                && ObjectUtils.equals(mId, ephemeralKey.mId)
+                && mLiveMode == ephemeralKey.mLiveMode
+                && ObjectUtils.equals(mObject, ephemeralKey.mObject)
+                && ObjectUtils.equals(mSecret, ephemeralKey.mSecret)
+                && ObjectUtils.equals(mType, ephemeralKey.mType);
+    }
+
+    @Override
+    public int hashCode() {
+        return ObjectUtils.hash(mObjectId, mCreated, mExpires, mId, mLiveMode, mObject, mSecret,
+                mType);
+    }
 }

stripe/src/main/java/com/stripe/android/CustomerEphemeralKey.java

@@ -10,8 +10,21 @@
 import org.json.JSONObject;
 
 class CustomerEphemeralKey extends AbstractEphemeralKey {
+    public static final Parcelable.Creator<CustomerEphemeralKey> CREATOR
+            = new Parcelable.Creator<CustomerEphemeralKey>() {
+
+        @Override
+        public CustomerEphemeralKey createFromParcel(Parcel in) {
+            return new CustomerEphemeralKey(in);
+        }
 
-    protected CustomerEphemeralKey(Parcel in) {
+        @Override
+        public CustomerEphemeralKey[] newArray(int size) {
+            return new CustomerEphemeralKey[size];
+        }
+    };
+
+    private CustomerEphemeralKey(@NonNull Parcel in) {
         super(in);
     }
 
@@ -37,33 +50,15 @@ protected CustomerEphemeralKey(
     }
 
     @SuppressWarnings("checkstyle:RedundantModifier") // Not actually redundant :|
-    public CustomerEphemeralKey(
-            @Nullable JSONObject jsonObject
-    ) throws JSONException {
+    public CustomerEphemeralKey(@Nullable JSONObject jsonObject) throws JSONException {
         super(jsonObject);
-
     }
 
-
     @NonNull
     String getCustomerId() {
         return mObjectId;
     }
 
-    public static final Parcelable.Creator<CustomerEphemeralKey> CREATOR
-            = new Parcelable.Creator<CustomerEphemeralKey>() {
-
-        @Override
-        public CustomerEphemeralKey createFromParcel(Parcel in) {
-            return new CustomerEphemeralKey(in);
-        }
-
-        @Override
-        public CustomerEphemeralKey[] newArray(int size) {
-            return new CustomerEphemeralKey[size];
-        }
-    };
-
     @Nullable
     static CustomerEphemeralKey fromString(@Nullable String rawJson) throws JSONException {
         return (CustomerEphemeralKey) AbstractEphemeralKey

stripe/src/main/java/com/stripe/android/model/AccountParams.java

@@ -1,7 +1,11 @@
 package com.stripe.android.model;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 
+import com.stripe.android.utils.ObjectUtils;
+
+import java.util.AbstractMap;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -12,10 +16,11 @@
  */
 public class AccountParams {
 
-    static final String API_PARAM_LEGAL_ENTITY = "legal_entity";
-    static final String API_TOS_SHOWN_AND_ACCEPTED = "tos_shown_and_accepted";
-    private Boolean mTosShownAndAccepted;
-    private Map<String, Object> mLegalEntity;
+    private static final String API_PARAM_LEGAL_ENTITY = "legal_entity";
+    private static final String API_TOS_SHOWN_AND_ACCEPTED = "tos_shown_and_accepted";
+
+    @Nullable private Boolean mTosShownAndAccepted;
+    @Nullable private Map<String, Object> mLegalEntity;
 
     /**
      * @param tosShownAndAccepted indicates that the platform showed the user the appropriate text
@@ -25,20 +30,20 @@ public class AccountParams {
      *                    created. Can contain any of the fields specified by legal_entity in the
      *                    API docs.
      *
-     *                    See {@linktourl https://stripe.com/docs/api#account_object-legal_entity}
+     *                  See https://stripe.com/docs/api/accounts/object#account_object-legal_entity
      *
-     *                    The object in the map is expected to be a string or a list or map of
-     *                    strings. All {@link StripeJsonModel} types have a toMap() function that
-     *                    can be used to convert the {@link StripeJsonModel} to map representation
-     *                    that can be passed in here.
+     *                  The object in the map is expected to be a string or a list or map of
+     *                  strings. All {@link StripeJsonModel} types have a toMap() function that
+     *                  can be used to convert the {@link StripeJsonModel} to map representation
+     *                  that can be passed in here.
      */
+    @NonNull
     public static AccountParams createAccountParams(
             boolean tosShownAndAccepted,
             Map<String, Object> legalEntity) {
-        AccountParams accountParams = new AccountParams()
+        return new AccountParams()
                 .setTosShownAndAccepted(tosShownAndAccepted)
                 .setLegalEntity(legalEntity);
-        return accountParams;
     }
 
     /**
@@ -47,6 +52,7 @@ public static AccountParams createAccountParams(
      *                            when this is true.
      * @return {@code this}, for chaining purposes
      */
+    @NonNull
     public AccountParams setTosShownAndAccepted(boolean tosShownAndAccepted) {
         mTosShownAndAccepted = tosShownAndAccepted;
         return this;
@@ -65,6 +71,7 @@ public AccountParams setTosShownAndAccepted(boolean tosShownAndAccepted) {
      *                    that can be passed in here.
      * @return {@code this}, for chaining purposes
      */
+    @NonNull
     public AccountParams setLegalEntity(Map<String, Object> legalEntity) {
         mLegalEntity = legalEntity;
         return this;
@@ -78,13 +85,27 @@ public AccountParams setLegalEntity(Map<String, Object> legalEntity) {
      */
     @NonNull
     public Map<String, Object> toParamMap() {
-        Map<String, Object> networkReadyMap = new HashMap<>();
-        Map<String, Object> tokenMap = new HashMap<>();
+        final Map<String, Object> networkReadyMap = new HashMap<>();
+        final AbstractMap<String, Object> tokenMap = new HashMap<>();
         tokenMap.put(API_TOS_SHOWN_AND_ACCEPTED, mTosShownAndAccepted);
         tokenMap.put(API_PARAM_LEGAL_ENTITY, mLegalEntity);
         networkReadyMap.put("account", tokenMap);
         removeNullAndEmptyParams(networkReadyMap);
         return networkReadyMap;
     }
 
+    @Override
+    public int hashCode() {
+        return ObjectUtils.hash(mTosShownAndAccepted, mLegalEntity);
+    }
+
+    @Override
+    public boolean equals(@Nullable Object obj) {
+        return this == obj || (obj instanceof AccountParams && typedEquals((AccountParams) obj));
+    }
+
+    private boolean typedEquals(@NonNull AccountParams accountParams) {
+        return ObjectUtils.equals(mTosShownAndAccepted, accountParams.mTosShownAndAccepted)
+                && ObjectUtils.equals(mLegalEntity, accountParams.mLegalEntity);
+    }
 }

stripe/src/main/java/com/stripe/android/model/Address.java

@@ -199,13 +199,13 @@ public boolean equals(Object obj) {
         return this == obj || (obj instanceof Address && typedEquals((Address) obj));
     }
 
-    private boolean typedEquals(@NonNull Address obj) {
-        return ObjectUtils.equals(mCity, obj.mCity)
-                && ObjectUtils.equals(mCountry, obj.mCountry)
-                && ObjectUtils.equals(mLine1, obj.mLine1)
-                && ObjectUtils.equals(mLine2, obj.mLine2)
-                && ObjectUtils.equals(mPostalCode, obj.mPostalCode)
-                && ObjectUtils.equals(mState, obj.mState);
+    private boolean typedEquals(@NonNull Address address) {
+        return ObjectUtils.equals(mCity, address.mCity)
+                && ObjectUtils.equals(mCountry, address.mCountry)
+                && ObjectUtils.equals(mLine1, address.mLine1)
+                && ObjectUtils.equals(mLine2, address.mLine2)
+                && ObjectUtils.equals(mPostalCode, address.mPostalCode)
+                && ObjectUtils.equals(mState, address.mState);
     }
 
     @Override
@@ -291,6 +291,5 @@ public Builder setState(@Nullable String state) {
         public Address build() {
             return new Address(this);
         }
-
     }
 }

stripe/src/main/java/com/stripe/android/model/BankAccount.java

@@ -5,6 +5,8 @@
 import androidx.annotation.Size;
 import androidx.annotation.StringDef;
 
+import com.stripe.android.utils.ObjectUtils;
+
 import org.json.JSONException;
 import org.json.JSONObject;
 
@@ -204,4 +206,27 @@ public static BankAccount fromJson(@Nullable JSONObject jsonObject) {
                 StripeJsonUtils.optString(jsonObject, FIELD_LAST4),
                 StripeJsonUtils.optString(jsonObject, FIELD_ROUTING_NUMBER));
     }
+
+    @Override
+    public int hashCode() {
+        return ObjectUtils.hash(mAccountHolderName, mAccountHolderType, mAccountNumber,
+                mBankName, mCountryCode, mCurrency, mFingerprint, mLast4, mRoutingNumber);
+    }
+
+    @Override
+    public boolean equals(@Nullable Object obj) {
+        return super.equals(obj) || (obj instanceof BankAccount && typedEquals((BankAccount) obj));
+    }
+
+    private boolean typedEquals(@NonNull BankAccount bankAccount) {
+        return ObjectUtils.equals(mAccountHolderName, bankAccount.mAccountHolderName)
+                && ObjectUtils.equals(mAccountHolderType, bankAccount.mAccountHolderType)
+                && ObjectUtils.equals(mAccountNumber, bankAccount.mAccountNumber)
+                && ObjectUtils.equals(mBankName, bankAccount.mBankName)
+                && ObjectUtils.equals(mCountryCode, bankAccount.mCountryCode)
+                && ObjectUtils.equals(mCurrency, bankAccount.mCurrency)
+                && ObjectUtils.equals(mFingerprint, bankAccount.mFingerprint)
+                && ObjectUtils.equals(mLast4, bankAccount.mLast4)
+                && ObjectUtils.equals(mRoutingNumber, bankAccount.mRoutingNumber);
+    }
 }