/// <summary>
/// Gets the value associated with the specified key.
/// </summary>
/// <param name="key">The key whose value to get.</param>
/// <param name="value">
/// When this method returns, the value associated with the specified key, if the key is found;
/// otherwise, the default value for the type of the value parameter.
/// This parameter is passed uninitialised.</param>
/// <returns>Returns true if an entry with the specified key exists; otherwise, false.</returns>
/// <exception cref="System.ArgumentNullException"><paramref name="key"/> is null.</exception>
public Boolean TryGetValue(String key, out String value)
{
// key can't be null
if (key == null)
{
throw new ArgumentNullException("key");
}
using (EtilicContext context = new EtilicContext())
{
// try to find the entry with the specified key
BundleConfigEntry entry = context.BundleConfiguration.SingleOrDefault(
x => x.BundleID.Equals(this.bundleID) && x.Key.Equals(key));
// return the default String value/false if it doesn't exist
if (entry == null)
{
value = default(String);
return(false);
}
// return the entry's value if it does
value = entry.Value;
// indicate success
return(true);
}
}
/// <summary>
/// Determines whether the current bundle's configuration contains
/// an entry with matching key and value.
/// </summary>
/// <param name="item">The entry to find.</param>
/// <returns>Returns true if the entry exists; otherwise, false.</returns>
public Boolean Contains(KeyValuePair <String, String> item)
{
using (EtilicContext context = new EtilicContext())
{
BundleConfigEntry entry = context.BundleConfiguration.SingleOrDefault(
x => x.BundleID.Equals(this.bundleID) && x.Key.Equals(item.Key) && x.Value.Equals(item.Value));
return(entry != null);
}
}
/// <summary>
///
/// </summary>
/// <param name="key"></param>
/// <param name="value"></param>
public void Add(String key, String value)
{
// the key cannot be null
if (key == null)
{
throw new ArgumentNullException("key");
}
// initialise a database connection
using (EtilicContext context = new EtilicContext())
{
// initialise a transaction to avoid a race condition which would allow
// a configuration entry with the specified key to be added between
// testing whether an entry for the specified key exists and adding
// the new entry
using (var transaction = context.Database.BeginTransaction())
{
try
{
// test whether the database contains an entry for this key
if (context.BundleConfiguration.Any(x => x.BundleID.Equals(this.bundleID) && x.Key.Equals(key)))
{
throw new ArgumentException("The specified key already exists.");
}
// initialise a new entry for this key, with the specified initial value
BundleConfigEntry entry = new BundleConfigEntry();
entry.BundleID = this.bundleID;
entry.Key = key;
entry.Value = value;
// add the key to the local collection
context.BundleConfiguration.Add(entry);
// save changes to the database and commit all changes
context.SaveChanges();
transaction.Commit();
}
catch (Exception ex)
{
// roll back the transaction
transaction.Rollback();
// throw an exception
throw new EtilicException(
@"Unable to add key to the bundle's configuration because the database transaction failed. See the inner exception for more details.", ex);
}
}
}
}
/// <summary>
/// Removes the entry with the specified key from the current bundle's configuration.
/// </summary>
/// <param name="key">The key of the entry to remove.</param>
/// <returns>Returns true if the entry is successfully removed; otherwise, false.</returns>
public Boolean Remove(String key)
{
if (key == null)
{
throw new ArgumentNullException("key");
}
using (EtilicContext context = new EtilicContext())
{
using (var transaction = context.Database.BeginTransaction())
{
try
{
// try to find the entry with the specified key
BundleConfigEntry entry = context.BundleConfiguration.SingleOrDefault(
x => x.BundleID.Equals(this.bundleID) && x.Key.Equals(key));
// return false if it doesn't exist
if (entry == null)
{
return(false);
}
// remove the entry from the local set
context.BundleConfiguration.Remove(entry);
// save all changes
context.SaveChanges();
transaction.Commit();
// the entry has successfully been removed
return(true);
}
catch (Exception)
{
// roll-back all changes
transaction.Rollback();
// indicate failure (the IDictionary specification doesn't want us to throw an exception)
return(false);
}
}
}
}
/// <summary>
/// Gets or sets the value of the entry with the specified key.
/// </summary>
/// <param name="key">The key of the entry whose value should be looked up.</param>
/// <returns>Returns the value of the entry with the specified key.</returns>
/// <exception cref="System.ArgumentNullException"><paramref name="key"/> is null.</exception>
/// <exception cref="System.Collections.Generic.KeyNotFoundException">No entry whose key is <paramref name="key"/> exists.</exception>
public String this[String key]
{
get
{
// key can't be null
if (key == null)
{
throw new ArgumentNullException("key");
}
using (EtilicContext context = new EtilicContext())
{
// try to get a configuration entry with the specified key
BundleConfigEntry entry = context.BundleConfiguration.SingleOrDefault(
x => x.BundleID.Equals(this.bundleID) && x.Key.Equals(key));
// throw an exception if it does not exist
if (entry == null)
{
throw new KeyNotFoundException();
}
// otherwise return the value
return(entry.Value);
}
}
set
{
// key can't be null
if (key == null)
{
throw new ArgumentNullException("key");
}
using (EtilicContext context = new EtilicContext())
{
using (var transaction = context.Database.BeginTransaction())
{
try
{
// try to get a configuration entry with the specified key
BundleConfigEntry entry = context.BundleConfiguration.SingleOrDefault(
x => x.BundleID.Equals(this.bundleID) && x.Key.Equals(key));
// create it if it doesn't exist
if (entry == null)
{
entry = new BundleConfigEntry();
entry.BundleID = this.bundleID;
entry.Key = key;
// add the entry to the local set
context.BundleConfiguration.Add(entry);
}
// update the entry
entry.Value = value;
// save all changes
context.SaveChanges();
transaction.Commit();
}
catch (Exception ex)
{
// roll-back all changes
transaction.Rollback();
// re-throw the exception
throw ex;
}
}
}
}
}
