/*
 * [TestZipRead.java]
 *
 * Summary: Example to read the elements of a Zip file sequentially.
 *
 * Copyright: (c) 2009-2017 Roedy Green, Canadian Mind Products, http://mindprod.com
 *
 * Licence: This software may be copied and used freely for any purpose but military.
 *          http://mindprod.com/contact/nonmil.html
 *
 * Requires: JDK 1.8+
 *
 * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/
 *
 * Version History:
 *  1.0 2008-06-06
 */
package com.mindprod.example;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import static java.lang.System.*;
/**
 * Example to read the elements of a Zip file sequentially.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.0 2008-06-06
 * @since 2008-06-06
 */
public final class TestZipRead
    {
    /**
     * read the elements of a Zip file sequentially.
     *
     * @param args not used
     *
     * @throws java.io.IOException if problems writing file a.zip
     */
    public static void main( String[] args ) throws IOException
        {
        // specify the name of the zip we are going to read
        final String zipFileName = "in.zip";
        // specify the name of the directory where extracted data will go.
        final String targetdir = "targetdir";
        final FileInputStream fis = new FileInputStream( zipFileName );
        final ZipInputStream zip = new ZipInputStream( fis );
        // loop for each entry
        while ( true )
            {
            final ZipEntry entry = zip.getNextEntry();
            if ( entry == null )
                {
                break;
                }
            // relative name with slashes to separate dirnames.
            final String elementName = entry.getName();
            // This code won't work if ZipOutputStream
            // was used to create the zip file. ZipEntry.getSize will
            // return -1. You will have to read the element in chunks
            // or estimate a biggest possible size.
            // See http://mindprod.com/products.html#FILETRANSFER
            // Filetransfer.copy will handle the chunking and does
            // not need to know the length in advance.
            final int fileLength = ( int ) entry.getSize();
            final byte[] wholeFile = new byte[ fileLength ];
            // read directly from ZIP after the zip entry.
            final int bytesRead = zip.read( wholeFile, 0, fileLength );
            // checking bytesRead, and repeating if you don't get item all is not shown.
            out.println( bytesRead + " bytes read from " + elementName );
            // were we will write the element as an external file
            final File elementFile = new File( targetdir, elementName );
            // make sure dirs exist to hold the external file
            //noinspection ResultOfMethodCallIgnored
            elementFile.getParentFile().mkdirs();
            final FileOutputStream fos = new FileOutputStream( elementFile );
            fos.write( wholeFile, 0, fileLength );
            fos.close();
            //noinspection ResultOfMethodCallIgnored
            elementFile.setLastModified( entry.getTime() );
            zip.closeEntry();
            }
        zip.close();
        }
    }