code: public INDArray textsToMatrix(String[] texts, TokenizerMode mode) {
          Integer[][] sequences = textsToSequences(texts);
          return sequencesToMatrix(sequences, mode);
      }
docs: Turns an array of texts into an ND4J matrix of shape
  (number of texts, number of words in vocabulary)
  
  @param texts input texts
  @param mode TokenizerMode that controls how to vectorize data
  @return resulting matrix representation