Add support endpoint for balance of multiple addresses at a given hei…

…ght (#74)

src/main/java/com/wavesplatform/wavesj/Balance.java

@@ -0,0 +1,47 @@
+package com.wavesplatform.wavesj;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import im.mak.waves.transactions.account.Address;
+
+import java.util.Objects;
+
+public class Balance {
+    private final Address address;
+    private final long balance;
+
+    public Balance(@JsonProperty("id") Address address,
+                   @JsonProperty("balance") long balance) {
+        this.address = Common.notNull(address, "Id");
+        this.balance = balance;
+    }
+
+    public Address getAddress() {
+        return address;
+    }
+
+    public long getBalance() {
+        return balance;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof Balance)) return false;
+        Balance balance1 = (Balance) o;
+        return getBalance() == balance1.getBalance() &&
+                Objects.equals(getAddress(), balance1.getAddress());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(getAddress(), getBalance());
+    }
+
+    @Override
+    public String toString() {
+        return "Balance{" +
+                "address=" + address +
+                ", balance=" + balance +
+                '}';
+    }
+}

src/main/java/com/wavesplatform/wavesj/Node.java

@@ -105,7 +105,18 @@ public long getBalance(Address address, int confirmations) throws IOException, N
                 .get("balance").asLong();
     }
 
-    //todo getBalances(height, Address...) for several addresses at height
+    public List<Balance> getBalances(List<Address> addresses) throws IOException, NodeException {
+        RequestBuilder request = get("/addresses/balance");
+        addresses.forEach(address -> request.addParameter("address", address.toString()));
+        return asType(request, TypeRef.BALANCES);
+    }
+
+    public List<Balance> getBalances(List<Address> addresses, int height) throws IOException, NodeException {
+        RequestBuilder request = get("/addresses/balance");
+        addresses.forEach(address -> request.addParameter("address", address.toString()));
+        request.addParameter("height", String.valueOf(height));
+        return asType(request, TypeRef.BALANCES);
+    }
 
     public BalanceDetails getBalanceDetails(Address address) throws IOException, NodeException {
         return asType(get("/addresses/balance/details/" + address.toString()), TypeRef.BALANCE_DETAILS);

src/main/java/com/wavesplatform/wavesj/json/TypeRef.java

@@ -26,6 +26,8 @@ public class TypeRef {
 
     public static final TypeReference<List<AssetDetails>> ASSETS_DETAILS = new TypeReference<List<AssetDetails>>() {};
 
+    public static final TypeReference<List<Balance>> BALANCES = new TypeReference<List<Balance>>() {};
+
     public static final TypeReference<BalanceDetails> BALANCE_DETAILS = new TypeReference<BalanceDetails>() {};
 
     public static final TypeReference<Block> BLOCK = new TypeReference<Block>() {};