de.pawlidi.openaletheia.license.LicenseGenerator.java Source code

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Here is the source code for de.pawlidi.openaletheia.license.LicenseGenerator.java

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/*
 * Copyright (C) 2016 Maximilian Pawlidi
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package de.pawlidi.openaletheia.license;

import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Serializable;
import java.security.interfaces.RSAPrivateKey;
import java.util.Properties;

import org.apache.commons.io.FileUtils;
import org.apache.commons.lang.StringUtils;

import de.pawlidi.openaletheia.LicenseException;
import de.pawlidi.openaletheia.base.model.License;
import de.pawlidi.openaletheia.utils.CipherUtils;
import de.pawlidi.openaletheia.utils.Converter;
import de.pawlidi.openaletheia.utils.PropertiesUtils;

/**
 * 
 * 
 * @author PAWLIDIM
 * 
 *         Create: 23:27:42 2015
 * 
 */
final class LicenseGenerator implements Serializable {

    private String privateKey;
    private Properties properties;

    /**
     * Constructor to construct new license generator.
     */
    public LicenseGenerator(final String privateKey) {
        super();
        this.properties = new Properties();
        this.privateKey = privateKey;
    }

    /**
     * Generate license properties for given license object.
     * 
     * @param license
     * @return licenseProperties
     * @throws LicenseException
     */
    public Properties generate(License license) throws LicenseException {

        // clear properties
        properties.clear();

        if (!StringUtils.isBlank(privateKey)) {

            // create license properties
            LicenseProperties.createProperties(properties, license);

            // create signature
            String signature = createSignature();

            // add signature
            PropertiesUtils.setStringProperty(properties, LicenseProperties.SIGNATURE, signature);
        }
        return properties;
    }

    private String createSignature() {
        // compute signature for properties
        String signature = CipherUtils.computeSignatureString(properties);
        // create rsa key object for private key
        RSAPrivateKey rsaPrivateKey = CipherUtils.buildPrivateKey(privateKey);
        // encrypt signature
        byte[] encryptedSignature = CipherUtils.encrypt(Converter.toBytes(signature), rsaPrivateKey);
        // covert encrypted signature to string
        signature = Converter.toString(encryptedSignature);
        return signature;
    }

    /**
     * Store properties to file with given file name and file description.
     * 
     * @param fileName
     * @param description
     * @throws LicenseException
     */
    public void storeLicense(final String fileName, final String description) throws LicenseException {
        if (properties.isEmpty()) {
            return;
        }

        OutputStream outputStream;

        try {
            outputStream = FileUtils.openOutputStream(new File(fileName));
        } catch (IOException openOutputStreamException) {
            throw new LicenseException("Could not write license information to file " + fileName);
        }

        try {
            properties.store(outputStream, description);
            outputStream.flush();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    /**
     * Dispose reserved fields.
     */
    public void dispose() {
        privateKey = null;
        properties.clear();
        properties = null;
    }
}