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JSON Codecs, Codec Factory and JSON utils for ActiveJ project.
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package io.activej.json;
import com.dslplatform.json.JsonReader;
import com.dslplatform.json.JsonWriter;
import io.activej.common.builder.AbstractBuilder;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import static com.dslplatform.json.JsonWriter.*;
public final class SubclassJsonCodec implements JsonCodec {
private final Map> tagToCodec = new HashMap<>();
private final Map, String> classToTag = new HashMap<>();
private SubclassJsonCodec() {
}
public static SubclassJsonCodec.Builder builder() {
return new SubclassJsonCodec().new Builder();
}
public final class Builder extends AbstractBuilder> {
private Builder() {}
public Builder with(Class type, JsonCodec codec) {
return with(type, type.getSimpleName(), codec);
}
public Builder with(Class type, String name, JsonCodec codec) {
tagToCodec.put(name, codec);
classToTag.put(type, name);
if (codec instanceof SubclassJsonCodec) {
tagToCodec.putAll(((SubclassJsonCodec) codec).tagToCodec);
classToTag.putAll(((SubclassJsonCodec) codec).classToTag);
}
return this;
}
@Override
protected SubclassJsonCodec doBuild() {
return SubclassJsonCodec.this;
}
}
@Override
public void write(JsonWriter writer, T value) {
writer.writeByte(OBJECT_START);
String tag = classToTag.get(value.getClass());
writer.writeString(tag);
writer.writeByte(SEMI);
//noinspection unchecked
JsonCodec codec = (JsonCodec) tagToCodec.get(tag);
codec.write(writer, value);
writer.writeByte(OBJECT_END);
}
@Override
public T read(JsonReader reader) throws IOException {
if (reader.last() != OBJECT_START) throw reader.newParseError("Expected '{'");
reader.getNextToken();
String key = reader.readKey();
JsonCodec codec = tagToCodec.get(key);
if (codec == null) throw reader.newParseError("Unexpected key: '" + key + "'");
T result = codec.read(reader);
if (reader.getNextToken() != OBJECT_END) throw reader.newParseError("Expected '}'");
return result;
}
}