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ByteBuffer POC [DO NOT MERGE] #1526

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ByteBuffer POC [DO NOT MERGE] #1526

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3b4d69a
byte buffer POC
VysotskiVadim Dec 15, 2022
7681a2c
use direct buffer
VysotskiVadim Dec 16, 2022
0b3affb
improve test
VysotskiVadim Dec 16, 2022
96c0c3a
improve performance
VysotskiVadim Jan 4, 2023
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50 changes: 50 additions & 0 deletions ...rections-models/src/main/java/com/mapbox/api/directions/v5/models/DirectionsResponse.java
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,14 @@
import com.mapbox.api.directions.v5.DirectionsAdapterFactory;
import com.mapbox.geojson.Point;
import com.mapbox.geojson.PointAsCoordinatesTypeAdapter;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;

Expand Down Expand Up @@ -146,6 +154,48 @@ public static DirectionsResponse fromJson(@NonNull String json) {
return gson.create().fromJson(json, DirectionsResponse.class).toBuilder().build();
}

public static DirectionsResponse fromJson(@NonNull ByteBuffer json, Charset charsets) {
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Thinking about ways we could access specific parts of the DirectionsResponse, rather than deserializing the entire object. The DirectionsResponse can be large, but if we could stream the components.

For example, could we stream the geometry? #1518

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@kmadsen , I'm not sure if I understood this idea correctly. Is the idea about keeping raw json response in memory and deserialise only during first access?

GsonBuilder gson = new GsonBuilder();
gson.registerTypeAdapterFactory(DirectionsAdapterFactory.create());
gson.registerTypeAdapter(Point.class, new PointAsCoordinatesTypeAdapter());
// rebuilding to ensure that underlying routes have assigned indices and UUID

InputStream is = new ByteBufferBackedInputStream(json);
InputStreamReader r = new InputStreamReader(is, charsets);
return gson.create().fromJson(r, DirectionsResponse.class).toBuilder().build();
}

private static class ByteBufferBackedInputStream extends InputStream {

ByteBuffer buf;

public ByteBufferBackedInputStream(ByteBuffer buf) {
this.buf = buf;
}

public synchronized int read() throws IOException {
if (!buf.hasRemaining()) {
return -1;
}
return buf.get() & 0xFF;
}

@Override
public int available() throws IOException {
return buf.remaining();
}

public synchronized int read(byte[] bytes, int off, int len) throws IOException {
if (!buf.hasRemaining()) {
return -1;
}

len = Math.min(len, buf.remaining());
buf.get(bytes, off, len);
return len;
}
}

/**
* Create a new instance of this class by passing in a formatted valid JSON String.
* <p>
Expand Down
23 changes: 23 additions & 0 deletions ...ions-models/src/test/java/com/mapbox/api/directions/v5/models/DirectionsResponseTest.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
package com.mapbox.api.directions.v5.models;

import androidx.annotation.NonNull;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonElement;
Expand All @@ -10,6 +11,9 @@
import com.mapbox.geojson.Point;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
Expand Down Expand Up @@ -83,6 +87,25 @@ public void fromJson_correctlyBuildsFromJson() throws Exception {
assertEquals(1, response.routes().size());
}

@Test
public void deserialization_from_byte_buffer() throws Exception {
String textJson = loadJsonFixture(DIRECTIONS_V5_PRECISION6_FIXTURE);
ByteBuffer buffer = putTextToDirectByteBuffer(textJson, StandardCharsets.UTF_8);

DirectionsResponse responseFromBuffer = DirectionsResponse.fromJson(buffer, StandardCharsets.UTF_8);
DirectionsResponse responseFromText = DirectionsResponse.fromJson(textJson);

assertEquals(responseFromText, responseFromBuffer);
}

@NonNull private ByteBuffer putTextToDirectByteBuffer(String textJson, Charset charset) {
byte[] json = textJson.getBytes(charset);
ByteBuffer buffer = ByteBuffer.allocateDirect(json.length);
buffer.put(json);
buffer.position(0);
return buffer;
}

@Test
public void testToFromJsonWithRealResponse() throws Exception {
Gson gson = new GsonBuilder().create();
Expand Down