liquibase.util.StreamUtil Maven / Gradle / Ivy

package liquibase.util;

import java.io.*;
import java.nio.charset.Charset;

import liquibase.resource.UtfBomAwareReader;

/**
 * Utilities for working with streams.
 */
public class StreamUtil {
	
	final public static String lineSeparator = System.getProperty("line.separator");
	
    public static String getLineSeparator() {
        return lineSeparator;
    }

    /**
     * Reads a stream until the end of file into a String and uses the machines
     * default encoding to convert to characters the bytes from the Stream.
     *
     * @param ins The InputStream to read.
     * @return The contents of the input stream as a String
     * @throws IOException If there is an error reading the stream.
     */
    public static String getStreamContents(InputStream ins) throws IOException {
        return getReaderContents(new UtfBomAwareReader(ins));
    }

    /**
     * Reads a stream until the end of file into a String and uses the machines
     * default encoding to convert to characters the bytes from the Stream.
     *
     * @param ins The InputStream to read.
     * @param  charsetName The name of a supported {@link java.nio.charset.Charset charset}
     * @return The contents of the input stream as a String
     * @throws IOException If there is an error reading the stream.
     */
	public static String getStreamContents(InputStream ins, String charsetName)
			throws IOException {
		UtfBomAwareReader reader;

		if (charsetName == null) {
			reader = new UtfBomAwareReader(ins);
		} else {
			String charsetCanonicalName = Charset.forName(charsetName).name();
			String encoding;

			reader = new UtfBomAwareReader(ins, charsetName);
			encoding = Charset.forName(reader.getEncoding()).name();

			if (charsetCanonicalName.startsWith("UTF")
					&& !charsetCanonicalName.equals(encoding)) {
				reader.close();
				throw new IllegalArgumentException("Expected encoding was '"
						+ charsetCanonicalName + "' but a BOM was detected for '"
						+ encoding + "'");
			}
		}
		return getReaderContents(reader);
	}
    
    /**
     * Reads all the characters into a String.
     *
     * @param reader The Reader to read.
     * @return The contents of the input stream as a String
     * @throws IOException If there is an error reading the stream.
     */
    public static String getReaderContents(Reader reader) throws IOException {
        try {
            StringBuffer result = new StringBuffer();

            char[] buffer = new char[2048];
            int read;
            while ((read = reader.read(buffer)) > -1) {
                result.append(buffer, 0, read);
            }
            return result.toString();
        } finally {
            try {
                reader.close();
            } catch (IOException ioe) {//NOPMD
                // can safely ignore
            }
        }
    }

    public static void copy(InputStream inputStream, OutputStream outputStream) throws IOException {
        byte[] bytes = new byte[1024];
        int r = inputStream.read(bytes);
        while (r > 0) {
            outputStream.write(bytes, 0, r);
            r = inputStream.read(bytes);
        }
    }
}