public interface IBlockChain {

    /**
     * Put data on the blockchain
     *
     * @param key  the key being used to put the data on the blockchain
     * @param data the data being put on the blockchain
     */
    public boolean put(String key, Record data);

    /**
     * Get data from the blockchain
     *
     * @param key the key being queried
     * @return
     */
    public List<Record> get(String key);

    /**
     * Get all data from the blockchain
     * @return
     */
    public List<Record> all();
}

	// define a multichain instance
	IBlockChain mc = new MultiChain(
                "http://127.0.0.1",
                4352,
                "chain1",
                "stream1",
                "multichainrpc",
                "BHcXLKwR218R883P6pjiWdBffdMx398im4R8BEwfAxMm");

	// provide the details about signing and hashing
	sign.AbstractExternalSignature sgn = new sign.DefaultExternalSignature(new File("path_to_keystore"), "demo", "password");

	// file being handled
	File inputFile = new File("input.pdf");

	// instantiate blockchain
	pdfchain.PdfChain blockchain = new pdfchain.PdfChain(mc, sgn);
	
	blockchain.put(inputFile);

	IBlockChain mc = new MultiChain(
                "http://127.0.0.1",
                4352,
                "chain1",
                "stream1",
                "multichainrpc",
                "BHcXLKwR218R883P6pjiWdBffdMx398im4R8BEwfAxMm");

	sign.AbstractExternalSignature sgn = new sign.DefaultExternalSignature(new File("path_to_keystore"), "demo", "password");

	File inputFile = new File("input.pdf");

	pdfchain.PdfChain blockchain = new pdfchain.PdfChain(mc, sgn);
	for (Map<String, Object> docEntry : blockchain.get(inputFile)) {
		for (Map.Entry<String, Object> entry : docEntry.entrySet())
			System.out.println(padRight(entry.getKey(), 32) + " : " + entry.getValue());
		System.out.println("");
	}

blocktime                        : 1499691151
id2                              : �Ʊ��B�}ә`�-o�R
id1                              : z�L{�Wd=������G�
publishers                       : [14pwDpkcfRvSiw6DJWpP7RdcYgv5NfRRn6Dudr]
txid                             : b0092d7eb967ac2e45671742ddf1a0a96bc049a4bbfe3528888b6d9ff396b7a2
hsh                              : ��B�������șo�$'�A�d��L����xR�U
confirmations                    : 22
key                              : ��B����ï¿½ï¿½ï¿½È o�$'�A�d��L����xR�U
shsh                             : <garbled>

	/* build query
	 * This query selects only those items with a specific id,
	 * with either less than 5, or more than 10 confirmations.
	 * It reduces the columns to ["id1", "id2", "blocktime", "confirmations"]
	 * and sorts the records (default ascending order) by the field "confirmations"
	 */
	AbstractBQLOperator op = new SortBy(new Select(
                                                new And(
                                                    new Or(
                                                        new Greater("confirmations", 10),
                                                        new Smaller("confirmations", 5)
                                                    ),
                                                    new EqualID("z�L{�Wd=��\u007F\u0010��G�")
                                                ),
                                                new String[]{"id1", "id2", "blocktime", "confirmations"}
                                            ),
                                            "confirmations");
	// set up blockchain
	IBlockChain mc = new MultiChain(
                "http://127.0.0.1",
                4352,
                "chain1",
                "stream1",
                "multichainrpc",
                "BHcXLKwR218R883P6pjiWdBffdMx398im4R8BEwfAxMm");
				
	Executor exe = new Executor(mc);
	Collection<Record> resultSet = exe.execute(op);

	IBlockChain mc = new MultiChain(
                "http://127.0.0.1",
                4352,
                "chain1",
                "stream1",
                "multichainrpc",
                "BHcXLKwR218R883P6pjiWdBffdMx398im4R8BEwfAxMm");

	// build query
	AbstractBQLOperator op = BQLCompiler.compile("SELECT [id1, id2, confirmations,hsh]( confirmations > 10 AND confirmations < 50 ) SORT confirmations");

	// build executor
	Executor exe = new Executor(mc);

	// execute query
	Collection<Record> resultSet = exe.execute(op);
	Assert.assertFalse(resultSet.isEmpty());

        // check signature
        for(Record r : chain.get("z�L{�Wd=��\u007F\u0010��G�")){
            if(chain.isSigned(r, sgn.getPublicKey()))
                System.out.println("This record is signed");
        }