ByteSizeValue to implement Writeable rather than Streamable

With this we can make ByteSizeValue immutable for real.

core/src/main/java/org/elasticsearch/common/unit/ByteSizeValue.java

@@ -23,20 +23,25 @@ import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
-import org.elasticsearch.common.io.stream.Streamable;
+import org.elasticsearch.common.io.stream.Writeable;
 
 import java.io.IOException;
 import java.util.Locale;
 import java.util.Objects;
 
-public class ByteSizeValue implements Streamable {
+public class ByteSizeValue implements Writeable {
 
-    private long size;
+    private final long size;
+    private final ByteSizeUnit sizeUnit;
 
-    private ByteSizeUnit sizeUnit;
-
-    private ByteSizeValue() {
+    public ByteSizeValue(StreamInput in) throws IOException {
+        size = in.readVLong();
+        sizeUnit = ByteSizeUnit.BYTES;
+    }
 
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        out.writeVLong(bytes());
     }
 
     public ByteSizeValue(long bytes) {
@@ -218,23 +223,6 @@ public class ByteSizeValue implements Streamable {
         return new ByteSizeValue(bytes, ByteSizeUnit.BYTES);
     }
 
-    public static ByteSizeValue readBytesSizeValue(StreamInput in) throws IOException {
-        ByteSizeValue sizeValue = new ByteSizeValue();
-        sizeValue.readFrom(in);
-        return sizeValue;
-    }
-
-    @Override
-    public void readFrom(StreamInput in) throws IOException {
-        size = in.readVLong();
-        sizeUnit = ByteSizeUnit.BYTES;
-    }
-
-    @Override
-    public void writeTo(StreamOutput out) throws IOException {
-        out.writeVLong(bytes());
-    }
-
     @Override
     public boolean equals(Object o) {
         if (this == o) {

core/src/main/java/org/elasticsearch/indices/recovery/RecoverFilesRecoveryException.java

@@ -57,7 +57,7 @@ public class RecoverFilesRecoveryException extends ElasticsearchException implem
     public RecoverFilesRecoveryException(StreamInput in) throws IOException{
         super(in);
         numberOfFiles = in.readInt();
-        totalFilesSize = ByteSizeValue.readBytesSizeValue(in);
+        totalFilesSize = new ByteSizeValue(in);
     }
 
     @Override

core/src/test/java/org/elasticsearch/common/unit/ByteSizeValueTests.java

@@ -20,9 +20,13 @@
 package org.elasticsearch.common.unit;
 
 import org.elasticsearch.ElasticsearchParseException;
+import org.elasticsearch.common.io.stream.BytesStreamOutput;
+import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.test.ESTestCase;
 import org.hamcrest.MatcherAssert;
 
+import java.io.IOException;
+
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
@@ -165,4 +169,20 @@ public class ByteSizeValueTests extends ESTestCase {
             assertThat(e.getMessage(), containsString("failed to parse setting [test]"));
         }
     }
+
+    public void testSerialization() throws IOException {
+        //negative values cannot be serialized at the moment, we do abs but that is not enough with Long.MIN_VALUE
+        long l = Long.MIN_VALUE;
+        while (l == Long.MIN_VALUE) {
+            l = randomLong();
+        }
+        ByteSizeValue byteSizeValue = new ByteSizeValue(Math.abs(l), randomFrom(ByteSizeUnit.values()));
+        try (BytesStreamOutput out = new BytesStreamOutput()) {
+            byteSizeValue.writeTo(out);
+            try (StreamInput in = out.bytes().streamInput()) {
+                ByteSizeValue deserializedByteSizeValue = new ByteSizeValue(in);
+                assertEquals(byteSizeValue, deserializedByteSizeValue);
+            }
+        }
+    }
 }