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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.fs4;
import com.yahoo.tensor.Tensor;
import com.yahoo.tensor.serialization.TypedBinaryFormat;
import com.yahoo.text.Utf8;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* A static utility for encoding values to the binary map representation used in fs4 packets.
*
* @author bratseth
*/
public class MapEncoder {
// TODO: Time to refactor
private static byte [] getUtf8(Object value) {
if (value == null) {
return Utf8.toBytes("");
} else if (value instanceof Tensor) {
return TypedBinaryFormat.encode((Tensor)value);
} else {
return Utf8.toBytes(value.toString());
}
}
/**
* Encodes a single value as a complete binary map.
* Does nothing if the value is null.
*
* Returns the number of maps encoded - 0 or 1
*/
public static int encodeSingleValue(String mapName, String key, Object value, ByteBuffer buffer) {
if (value == null) return 0;
byte [] utf8 = Utf8.toBytes(mapName);
buffer.putInt(utf8.length);
buffer.put(utf8);
buffer.putInt(1);
utf8 = Utf8.toBytes(key);
buffer.putInt(utf8.length);
buffer.put(utf8);
utf8 = getUtf8(value);
buffer.putInt(utf8.length);
buffer.put(utf8);
return 1;
}
/**
* Encodes a map as binary.
* Does nothing if the value is null.
*
* Returns the number of maps encoded - 0 or 1
*/
public static int encodeMap(String mapName, Map<String,?> map, ByteBuffer buffer) {
if (map.isEmpty()) return 0;
byte [] utf8 = Utf8.toBytes(mapName);
buffer.putInt(utf8.length);
buffer.put(utf8);
buffer.putInt(map.size());
for (Map.Entry<String, ?> entry : map.entrySet()) {
String key = entry.getKey();
utf8 = Utf8.toBytes(key);
buffer.putInt(utf8.length);
buffer.put(utf8);
Object value = entry.getValue();
utf8 = getUtf8(value);
buffer.putInt(utf8.length);
buffer.put(utf8);
}
return 1;
}
/**
* Encodes a multi-map as binary.
* Does nothing if the value is null.
*
* Returns the number of maps encoded - 0 or 1
*/
public static <T> int encodeMultiMap(String mapName, Map<String,List<T>> map, ByteBuffer buffer) {
if (map.isEmpty()) return 0;
byte[] utf8 = Utf8.toBytes(mapName);
buffer.putInt(utf8.length);
buffer.put(utf8);
buffer.putInt(countEntries(map));
for (Map.Entry<String, List<T>> property : map.entrySet()) {
String key = property.getKey();
for (Object value : property.getValue()) {
utf8 = Utf8.toBytes(key);
buffer.putInt(utf8.length);
buffer.put(utf8);
utf8 = getUtf8(value);
buffer.putInt(utf8.length);
buffer.put(utf8);
}
}
return 1;
}
private static <T> int countEntries(Map<String, List<T>> value) {
int entries = 0;
for (Map.Entry<String, List<T>> property : value.entrySet())
entries += property.getValue().size();
return entries;
}
}
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