DataReader.java - Convert Byte Array To Integer/Long/Float/Double

DataReader.java

package references;

import java.io.IOException;
import java.io.InputStream;

import android.util.Log;

abstract class DataReader {

	public static final int INVALID_DATA = -1;
	private InputStream dis = null;
	
	protected DataReader(InputStream is) {
		dis = is;
	}
	
	public abstract boolean read();
	
	protected float readFloat() {
		int value = readInt();
		if (value != INVALID_DATA) {
			return Float.intBitsToFloat(value);
		}
		return INVALID_DATA;
	}
	
	protected int readInt() {
		byte[] bytes = readBytes(4);
		if (bytes != null) {
			int value = 0;
			value += (bytes[3] & 0x000000FF) << 24;
			value += (bytes[2] & 0x000000FF) << 16;
			value += (bytes[1] & 0x000000FF) << 8;
			value += (bytes[0] & 0x000000FF);
			return value;
		}
		return INVALID_DATA;
	}
	
	protected double readDouble() {
		long value = readLong();
		if (value != INVALID_DATA) {
			return Double.longBitsToDouble(value);
		}
		return INVALID_DATA;
	}
	
	protected long readLong() {
		byte[] bytes = readBytes(8);
		if (bytes != null) {
			long value = 0;
			value += (long) (bytes[7] & 0x000000FF) << 56;
			value += (long) (bytes[6] & 0x000000FF) << 48;
			value += (long) (bytes[5] & 0x000000FF) << 40;
			value += (long) (bytes[4] & 0x000000FF) << 32;
			value += (bytes[3] & 0x000000FF) << 24;
			value += (bytes[2] & 0x000000FF) << 16;
			value += (bytes[1] & 0x000000FF) << 8;
			value += (bytes[0] & 0x000000FF);
			return value;
		}
		return INVALID_DATA;
	}
	
	protected void skipBytes(int length) {
		try {
			int count = (int) dis.skip(length);
			if (count != length) {
				Log.i("Incorrect Data Size (Intended:Actual): ",
					String.valueOf(length) + ":" + String.valueOf(count));
			}
		} catch (IOException ex) {
			Log.w("[email protected]()", ex);
		}
	}
	
	protected void readBytes(int length) {
		byte[] bytes = new byte[length];
		try {
			int count = dis.read(bytes, 0, length);
			if (count != length) {
				Log.i("Incorrect Data Size (Intended:Actual): ",
					String.valueOf(length) + ":" + String.valueOf(count));
				return null;
			}
			return bytes;
		} catch (IOException ex) {
			Log.w("[email protected]()", ex);
		}
		return null;
	}
}

i will share other solution in java convert string to int
In Java 8 using stream API we can convert set of String to set of Integer, it involves following steps like,

1. The Set.Stream() is used to convert set to stream.

2. The Steam.map() is used to convert stream to stream.

3. The Collectorts.toset() is used to Accumulate stream to set.

4. The map() operation is used to throw NumberFormatException, if string does not contains parsable integer.

Is the return type of the readBytes wrong? Its returns a bytes array on line 86, yet the return type is void.