shubham0204 / Text2Summary-Android

A library for Text Summarization on Android applications.

Text2Summary API

Text2Summary API uses on-device methods to perform text summarization on Android applications. It uses extractive text summarization to give you the most important sentences from a given text.

You may read the story of Text2Summary on Medium.

• Installation
• Usage
• More on Text2Summary
• Contribute

Please note that this library is in development. So, it will be prone to frequent changes. Developers are welcomed to open issues and share their feedback.

Installation

First, we need to add the JitPack Maven repository to the root-level build.gradle file,

allprojects {
    repositories {
        // Other dependencies
        maven { url 'https://jitpack.io' }
    }
}

Then in the module-level build.gradle file, add the Text2Summary dependency,

dependencies {
    // Other dependencies
    implementation 'com.github.shubham0204:Text2Summary-Android:alpha-05'
}

For the latest build, see Releases.

Usage

The text which needs to be summarized has to be a String object. Then, use Text2Summary.summarize() method to generate the summary.

var summary = Text2Summary.summarize( someLongText , compressionRate = 0.7 )

The number 0.7 is referred as the compression factor. Meaning, given a text of 10 sentences, a summary of 7 sentences will be produced. This number must lie in the interval ( 0 , 1 ].

You may extract text from a file and then pass it to Text2Summary,

val bufferedReader: BufferedReader = File( "poems.txt" ).bufferedReader()
val text = bufferedReader.use{ it.readText() }
val summary = Text2Summary.summarize( text , 0.7 )

Using Text2Summary for huge texts

As heavy operations are performed for the summarization, a huge text given to Text2Summary may block the Activity UI thread.
To counter this, use Text2Summary.summarizeAsync(),

val callback = object : Text2Summary.SummaryCallback {
    override fun onSummaryProduced(summary: String) {
        // The summary is ready!
    }
}
Text2Summary.summarizeAsync( someLongText , 0.7f , callback  )

The summarizeAsync() method internally calls the summarize() method itself wrapped in a AsyncTask.

More on Text2Summary

Text2Summary uses the TF-IDF algorithm for extractive text summarization. Note, this is not abstractive text summarization which use neural networks like the Seq2Seq model. As TensorFlow Lite does not support fully the conversion of Embedding and LSTM layers, we need to use the TF-IDF algorithm.

1. The text which is given to TextSummary.summarize() is broken down into sentences. These sentences are further brought down to words ( tokens ).
2. Using TF-IDF algorithm, a TF-IDF score is calculated for each word.
3. Next, we take the sum of such scores for all words present in the sentence.
4. Finally, we take the top N highest scores. The corresponding sentences hold most of the information present in the text. These sentences are then concatenated and returned as the summary.

Updates

With TensorFlow 2.3, some LSTM and Embedding ops are now supported with TensorFlow Lite. But I'll stick to TF-IDF as it is faster and efficient for Android.

Contribute

If you are facing any issues, open an issue on the repository. You may send your suggestion at [e-mail].