SaveStateManager.java

/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * 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 com.motorolamobility.studio.android.certmanager.core;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Calendar;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Properties;
import java.util.Set;
import java.util.StringTokenizer;

import com.motorola.studio.android.common.log.StudioLogger;
import com.motorolamobility.studio.android.certmanager.CertificateManagerActivator;
import com.motorolamobility.studio.android.certmanager.views.KeystoreManagerView;

/**
 * Saves the state of the {@link KeystoreManagerView} with:
 * - the keystores mapped
 * - the last backup date from a keystore
 */
class SaveStateManager
{
    private static final String FILE_COMMENT = "-- Signing and keys view persistence --";

    private static final String STATE_FILENAME = "state.properties";

    private final File persistenceFile = new File(System.getProperty("user.home") + File.separator
            + "." + CertificateManagerActivator.PLUGIN_ID, STATE_FILENAME);

    private static final String KEYSTORE_TYPE = "keystore_type=";

    private static final String BACKUP_DATE = "backup_date=";

    protected class ViewStateEntry
    {
        private final File keystoreFile;

        private String keystoreType;

        private Date backupDate;

        public ViewStateEntry(File keystoreFile)
        {

            this.keystoreFile = keystoreFile;
        }

        public ViewStateEntry(File keystoreFile, String keystoreType)
        {

            this.keystoreFile = keystoreFile;
            this.keystoreType = keystoreType;
        }

        /**
         * @return the backupDate
         */
        public Date getBackupDate()
        {
            return backupDate;
        }

        /**
         * @param backupDate the backupDate to set
         */
        public void setBackupDate(Date backupDate)
        {
            this.backupDate = backupDate;
        }

        /**
         * @return the keystoreType
         */
        public String getKeystoreType()
        {
            return keystoreType;
        }

        /**
         * @param keystoreType the keystoreType to set
         */
        public void setKeystoreType(String keystoreType)
        {
            this.keystoreType = keystoreType;
        }

        /* (non-Javadoc)
         * @see java.lang.Object#toString()
         */
        @Override
        public String toString()
        {
            return "ViewStateEntry [keystoreFile=" + keystoreFile + ", keystoreType="
                    + keystoreType + ", backupDate=" + backupDate + "]";
        }

        /**
         * @return the keystoreFile
         */
        protected File getKeystoreFile()
        {
            return keystoreFile;
        }
    }

    private static SaveStateManager _instance;

    /**
     * This class is a singleton.
     * @return The unique instance of this class.
     * */
    public synchronized static SaveStateManager getInstance() throws IOException
    {
        if (_instance == null)
        {
            _instance = new SaveStateManager();
        }
        return _instance;
    }

    private SaveStateManager() throws IOException
    {
        //create folder if it does not exist
        if (!persistenceFile.getParentFile().exists())
        {
            persistenceFile.getParentFile().mkdirs();
        }
        if (!persistenceFile.exists())
        {
            //init file
            persistenceFile.createNewFile();
            store(new Properties());
        }
    }

    private String write(ViewStateEntry entry)
    {
        StringBuffer buffer = new StringBuffer();
        if (entry.getKeystoreType() != null)
        {
            buffer.append(KEYSTORE_TYPE + entry.getKeystoreType() + File.pathSeparator);
        }
        if (entry.getBackupDate() != null)
        {
            buffer.append(BACKUP_DATE + entry.getBackupDate().getTime());
        }
        return buffer.toString();
    }

    /**
     * List all mapped keystores.
     * @throws IOException If there are problems loading the persistence file.
     */
    public Set<File> getMappedKeystores() throws IOException
    {
        Set<File> mappedKeystores = new HashSet<File>();
        Properties properties = load();
        Enumeration<Object> enumeration = properties.keys();
        while (enumeration.hasMoreElements())
        {
            Object k = enumeration.nextElement();
            if (k instanceof String)
            {
                String key = (String) k;
                File keystoreFile = new File(key);
                mappedKeystores.add(keystoreFile);
            }
        }
        return mappedKeystores;
    }

    /**
     * Get a representation of the entry saved in the persistence.
     * @param keystoreFile The file that will have its state retrieved.     
     * @return 
     * @throws IOException If there are problems loading the persistence file.
     */
    public ViewStateEntry getEntry(File keystoreFile) throws IOException
    {
        Properties properties = load();
        Object v = properties.get(keystoreFile.getAbsolutePath());
        ViewStateEntry entry = null;
        if (v instanceof String)
        {
            String value = (String) v;
            StringTokenizer stringTokenizer = new StringTokenizer(value, File.pathSeparator);
            entry = new ViewStateEntry(keystoreFile);
            while (stringTokenizer.hasMoreTokens())
            {
                String token = stringTokenizer.nextToken();
                if (token.contains(KEYSTORE_TYPE))
                {
                    token = token.substring(KEYSTORE_TYPE.length());
                    entry.setKeystoreType(token);
                }
                else if (token.contains(BACKUP_DATE))
                {
                    token = token.substring(BACKUP_DATE.length());
                    Calendar calendar = Calendar.getInstance();
                    calendar.setTimeInMillis(Long.parseLong(token));
                    Date date = calendar.getTime();
                    entry.setBackupDate(date);
                }
            }
        }
        return entry;
    }

    /**
     * Check if a keystore is mapped on the persistence mechanism.
     * @param keystoreFile The keystore to be checked.
     * @return true if keystore mapped, false otherwise
     * @throws IOException If there are problems loading the persistence file.
     */
    public boolean isKeystoreMapped(File keystoreFile) throws IOException
    {
        Properties properties = load();
        return properties.containsKey(keystoreFile.getAbsolutePath());
    }

    /**
     * Adds (maps) a keystore.
     * @param keystoreFile The keystore to be added to the persistence mechanism.
     * @param keystoreType The type of the keystore.
     * @throws IOException If there are problems loading the persistence file.
     */
    public void addEntry(File keystoreFile, String keystoreType) throws IOException
    {
        ViewStateEntry stateEntry = new ViewStateEntry(keystoreFile, keystoreType);
        addEntry(keystoreFile, stateEntry);
    }

    private void addEntry(File keystoreFile, ViewStateEntry stateEntry) throws IOException
    {
        Properties prop = load();
        prop.setProperty(keystoreFile.getAbsolutePath(), write(stateEntry));
        store(prop);
    }

    /**
     * Removes a keystore from the persistence mechanism.
     * @param keystoreFile
     * @throws IOException
     */
    public void removeEntry(File keystoreFile) throws IOException
    {
        Properties properties = load();
        properties.remove(keystoreFile.getAbsolutePath());
        store(properties);
    }

    /**
     * Sets backup date from a keystore 
     * @param keystoreFile The keystore file.
     * @param backupDate The date of the backup.
     * @throws IOException If there are problems loading the persistence file.
     */
    public void setBackupDate(File keystoreFile, Date backupDate) throws IOException
    {
        ViewStateEntry entry = getEntry(keystoreFile);
        entry.setBackupDate(backupDate);
        addEntry(keystoreFile, entry);
    }

    private Properties load() throws IOException
    {
        FileInputStream in = null;
        Properties props = new Properties();

        try
        {
            in = new FileInputStream(persistenceFile);
            props.loadFromXML(in);
        }
        finally
        {
            if (in != null)
            {
                in.close();
            }
        }
        return props;
    }

    private void store(Properties prop) throws IOException
    {
        FileOutputStream out = null;

        try
        {
            out = new FileOutputStream(persistenceFile);
            prop.storeToXML(out, FILE_COMMENT);
        }
        finally
        {
            if (out != null)
            {
                try
                {
                    out.close();
                }
                catch (IOException e)
                {
                    StudioLogger.error("Could not close stream while saving properties. "
                            + e.getMessage());
                }
            }
        }
    }
}