com.weaverplatform.protocol.SortedWriteOperationParser Maven / Gradle / Ivy

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package com.weaverplatform.protocol;

import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import com.google.gson.reflect.TypeToken;
import com.google.gson.stream.JsonReader;
import com.weaverplatform.protocol.model.*;

import java.io.*;

import java.util.Set;
import java.util.TreeSet;

import static com.weaverplatform.util.SortUtil.*;

/**
 * @author bastbijl
 */
public class SortedWriteOperationParser extends WriteOperationParser {

  public SortedWriteOperationParser(Reader reader) {
    super(reader);
  }

  public SortedWriteOperationParser(InputStream stream) throws UnsupportedEncodingException {
    super(stream);
  }

  public static Character sortChar(String id) {
    if(id == null || id.trim().isEmpty()) {
      return Character.MIN_VALUE;
    }
    return id.charAt(id.length()-1); // use last character
  }

  public static Set startChars(InputStream stream) throws IOException {
    TreeSet set = new TreeSet<>(charComparator);
    JsonReader reader = new JsonReader(new InputStreamReader(stream, "UTF-8"));
    reader.beginArray();

    while(reader.hasNext()) {
      String id = sortKey(gson.fromJson(reader, new TypeToken(){}.getType()));
      Character sc = sortChar(id);
      set.add(sc);
    }
    return set;
  }

  public TreeSet parseNextSorted(int chunkSize, Character filter) throws IOException {

    if(jsonReader == null) {
      jsonReader = new JsonReader(sourceReader);
      jsonReader.beginArray();
    }

    TreeSet set = new TreeSet<>(writeOperationComparator);
    while(jsonReader.hasNext() && (chunkSize == -1 || set.size() < chunkSize)) {
      WriteOperation operation;
      if(includePayload) {
        JsonObject source = JsonParser.parseReader(jsonReader).getAsJsonObject();
        operation = gson.fromJson(source, new TypeToken() {}.getType());
        operation.setPayload(source.toString());
      } else {
        operation = gson.fromJson(jsonReader, new TypeToken() {}.getType());
      }
      if (filter == null || filter.equals(sortChar(sortKey(operation)))) {
        if(defaultCreator != null) {
          operation.setUser(defaultCreator);
        }
        set.add(operation);
      }
    }

    return set;
  }
}