Implement Horizon Protocol 14 API changes (#295)

This PR implements support for Horizon's Protocol 14 API changes.

build.gradle

@@ -47,7 +47,8 @@ dependencies {
     compile 'com.google.code.gson:gson:2.8.5'
     compile 'commons-io:commons-io:2.6'
     compile 'net.i2p.crypto:eddsa:0.3.0'
-
+    compile 'org.threeten:threetenbp:1.4.4'
+
     testCompile 'org.mockito:mockito-core:2.21.0'
     testCompile "com.squareup.okhttp3:mockwebserver:${okhttpclientVersion}"
     testCompile 'junit:junit:4.12'

src/main/java/org/stellar/sdk/Asset.java

@@ -7,6 +7,23 @@
 public abstract class Asset {
   Asset() {}
 
+  /**
+   * Parses an asset string and returns the equivalent Asset instance.
+   * The asset string is expected to either be "native" or a string of the form "CODE:ISSUER"
+   *
+   * @param canonicalForm Canonical string representation of an asset
+   */
+  public static Asset create(String canonicalForm) {
+    if (canonicalForm.equals("native")) {
+      return new AssetTypeNative();
+    }
+    String [] parts = canonicalForm.split(":");
+    if (parts.length != 2) {
+      throw new IllegalArgumentException("invalid asset "+ canonicalForm);
+    }
+    return Asset.createNonNativeAsset(parts[0], parts[1]);
+  }
+
   public static Asset create(String type, String code, String issuer) {
     if (type.equals("native")) {
       return new AssetTypeNative();

src/main/java/org/stellar/sdk/AssetTypeCreditAlphaNum.java

@@ -34,6 +34,11 @@ public String getIssuer() {
         return new String(mIssuer);
     }
 
+    @Override
+    public String toString() {
+        return getCode() + ":" + getIssuer();
+    }
+
     @Override
     public int hashCode() {
         return Objects.hashCode(this.mCode, this.mIssuer);

src/main/java/org/stellar/sdk/AssetTypeNative.java

@@ -10,6 +10,11 @@ public final class AssetTypeNative extends Asset {
 
   public AssetTypeNative() {}
 
+  @Override
+  public String toString() {
+    return "native";
+  }
+
   @Override
   public String getType() {
     return "native";

src/main/java/org/stellar/sdk/Claimant.java

@@ -0,0 +1,28 @@
+package org.stellar.sdk;
+
+import com.google.gson.annotations.SerializedName;
+import org.stellar.sdk.Predicate;
+
+/**
+ * Represents an entity who is eligible to claim the claimable balance.
+ */
+public class Claimant {
+  @SerializedName("destination")
+  private final String destination;
+  @SerializedName("predicate")
+  private final Predicate predicate;
+
+  public Claimant(String destination, Predicate predicate) {
+    this.destination = destination;
+    this.predicate = predicate;
+  }
+
+  public String getDestination() {
+    return destination;
+  }
+
+  public Predicate getPredicate() {
+    return predicate;
+  }
+
+}

src/main/java/org/stellar/sdk/Predicate.java

@@ -0,0 +1,255 @@
+package org.stellar.sdk;
+
+import com.google.common.base.Objects;
+import com.google.common.collect.Lists;
+import org.stellar.sdk.xdr.ClaimPredicate;
+import org.stellar.sdk.xdr.ClaimPredicateType;
+import org.stellar.sdk.xdr.Int64;
+import org.threeten.bp.Instant;
+
+import java.util.Date;
+import java.util.List;
+
+public abstract class Predicate {
+
+  private static List<Predicate> convertXDRPredicates(ClaimPredicate[] predicates) {
+    List<Predicate> list = Lists.newArrayList();
+    for (ClaimPredicate p : predicates) {
+      list.add(fromXdr(p));
+    }
+    return list;
+  }
+
+  /**
+   * Generates Predicate object from a given XDR object
+   * @param xdr XDR object
+   */
+  public static Predicate fromXdr(org.stellar.sdk.xdr.ClaimPredicate xdr) {
+    switch (xdr.getDiscriminant()) {
+      case CLAIM_PREDICATE_UNCONDITIONAL:
+        return new Unconditional();
+      case CLAIM_PREDICATE_AND:
+        return new And(convertXDRPredicates(xdr.getAndPredicates()));
+      case CLAIM_PREDICATE_OR:
+        return new Or(convertXDRPredicates(xdr.getOrPredicates()));
+      case CLAIM_PREDICATE_NOT:
+        return new Not(fromXdr(xdr.getNotPredicate()));
+      case CLAIM_PREDICATE_BEFORE_RELATIVE_TIME:
+        return new RelBefore(xdr.getRelBefore().getInt64());
+      case CLAIM_PREDICATE_BEFORE_ABSOLUTE_TIME:
+        return new AbsBefore(xdr.getAbsBefore().getInt64());
+      default:
+        throw new IllegalArgumentException("Unknown asset type " + xdr.getDiscriminant());
+    }
+  }
+
+  @Override
+  public abstract boolean equals(Object object);
+
+  /**
+   * Generates XDR object from a given Asset object
+   */
+  public abstract org.stellar.sdk.xdr.ClaimPredicate toXdr();
+
+  public static class Unconditional extends Predicate {
+    @Override
+    public boolean equals(Object o) {
+      return (this == o) || (getClass() == o.getClass());
+    }
+
+    @Override
+    public int hashCode() {
+      return 0;
+    }
+
+    @Override
+    public ClaimPredicate toXdr() {
+      org.stellar.sdk.xdr.ClaimPredicate xdr = new org.stellar.sdk.xdr.ClaimPredicate();
+      xdr.setDiscriminant(ClaimPredicateType.CLAIM_PREDICATE_UNCONDITIONAL);
+      return xdr;
+    }
+  }
+
+  public static class Not extends Predicate {
+    private final Predicate inner;
+    public Not(Predicate inner) {
+      this.inner = inner;
+    }
+
+    public Predicate getInner() {
+      return inner;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      if (this == o) {
+        return true;
+      }
+      return (getClass() == o.getClass()) && Objects.equal(inner, ((Not)o).inner);
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hashCode(inner);
+    }
+
+    @Override
+    public ClaimPredicate toXdr() {
+      org.stellar.sdk.xdr.ClaimPredicate xdr = new org.stellar.sdk.xdr.ClaimPredicate();
+      xdr.setDiscriminant(ClaimPredicateType.CLAIM_PREDICATE_NOT);
+      xdr.setNotPredicate(inner.toXdr());
+      return xdr;
+    }
+  }
+
+  public static class Or extends Predicate {
+    private final List<Predicate> inner;
+
+    public Or(List<Predicate> inner) {
+      this.inner = inner;
+    }
+
+    public List<Predicate> getInner() {
+      return inner;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      if (this == o) {
+        return true;
+      }
+      return (getClass() == o.getClass()) && Objects.equal(inner, ((Or)o).inner);
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hashCode(inner);
+    }
+
+    @Override
+    public ClaimPredicate toXdr() {
+      org.stellar.sdk.xdr.ClaimPredicate xdr = new org.stellar.sdk.xdr.ClaimPredicate();
+      xdr.setDiscriminant(ClaimPredicateType.CLAIM_PREDICATE_OR);
+      ClaimPredicate[] xdrInner = new ClaimPredicate[inner.size()];
+      for (int i = 0; i < inner.size(); i++) {
+        xdrInner[i] = inner.get(i).toXdr();
+      }
+      xdr.setOrPredicates(xdrInner);
+      return xdr;
+    }
+  }
+
+
+  public static class And extends Predicate {
+    private final List<Predicate> inner;
+
+    public And(List<Predicate> inner) {
+      this.inner = inner;
+    }
+
+    public List<Predicate> getInner() {
+      return inner;
+    }
+
+
+    @Override
+    public boolean equals(Object o) {
+      if (this == o) {
+        return true;
+      }
+      return (getClass() == o.getClass()) && Objects.equal(inner, ((And)o).inner);
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hashCode(inner);
+    }
+
+    @Override
+    public ClaimPredicate toXdr() {
+      org.stellar.sdk.xdr.ClaimPredicate xdr = new org.stellar.sdk.xdr.ClaimPredicate();
+      xdr.setDiscriminant(ClaimPredicateType.CLAIM_PREDICATE_AND);
+      ClaimPredicate[] xdrInner = new ClaimPredicate[inner.size()];
+      for (int i = 0; i < inner.size(); i++) {
+        xdrInner[i] = inner.get(i).toXdr();
+      }
+      xdr.setAndPredicates(xdrInner);
+      return xdr;
+    }
+  }
+
+  public static class AbsBefore extends Predicate {
+    private final long epochSeconds;
+
+    public AbsBefore(long epochSeconds) {
+      this.epochSeconds = epochSeconds;
+    }
+
+    public long getTimestampSeconds() {
+      return epochSeconds;
+    }
+
+    public Instant getDate() {
+      return Instant.ofEpochSecond(epochSeconds);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      if (this == o) {
+        return true;
+      }
+      return (getClass() == o.getClass()) && Objects.equal(epochSeconds, ((AbsBefore)o).epochSeconds);
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hashCode(epochSeconds);
+    }
+
+    @Override
+    public ClaimPredicate toXdr() {
+      org.stellar.sdk.xdr.ClaimPredicate xdr = new org.stellar.sdk.xdr.ClaimPredicate();
+      xdr.setDiscriminant(ClaimPredicateType.CLAIM_PREDICATE_BEFORE_ABSOLUTE_TIME);
+      Int64 t = new Int64();
+      t.setInt64(epochSeconds);
+      xdr.setAbsBefore(t);
+      return xdr;
+    }
+  }
+
+  public static class RelBefore extends Predicate {
+    private final long secondsSinceClose;
+
+    public RelBefore(long secondsSinceClose) {
+      this.secondsSinceClose = secondsSinceClose;
+    }
+
+    public long getSecondsSinceClose() {
+      return secondsSinceClose;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      if (this == o) {
+        return true;
+      }
+      return (getClass() == o.getClass()) && Objects.equal(secondsSinceClose, ((RelBefore)o).secondsSinceClose);
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hashCode(secondsSinceClose);
+    }
+
+    @Override
+    public ClaimPredicate toXdr() {
+      org.stellar.sdk.xdr.ClaimPredicate xdr = new org.stellar.sdk.xdr.ClaimPredicate();
+      xdr.setDiscriminant(ClaimPredicateType.CLAIM_PREDICATE_BEFORE_RELATIVE_TIME);
+      Int64 t = new Int64();
+      t.setInt64(secondsSinceClose);
+      xdr.setRelBefore(t);
+      return xdr;
+    }
+  }
+
+  }

src/main/java/org/stellar/sdk/Server.java

@@ -126,6 +126,13 @@ public AssetsRequestBuilder assets() {
         return new AssetsRequestBuilder(httpClient, serverURI);
     }
 
+    /**
+     * Returns {@link ClaimableBalancesRequestBuilder} instance.
+     */
+    public ClaimableBalancesRequestBuilder claimableBalances() {
+        return new ClaimableBalancesRequestBuilder(httpClient, serverURI);
+    }
+
     /**
      * Returns {@link EffectsRequestBuilder} instance.
      */