From: David ‘Bombe’ Roden <bombe@pterodactylus.net>
Date: Mon, 25 Oct 2010 05:26:27 +0000 (+0200)
Subject: Add containers for various run-time options.
X-Git-Tag: 0.1-RC1~39
X-Git-Url: https://git.pterodactylus.net/?a=commitdiff_plain;h=a93ce25138d3799324bb0fba0cff589f9b83cc23;p=Sone.git

Add containers for various run-time options.
---

diff --git a/src/main/java/net/pterodactylus/sone/core/Options.java b/src/main/java/net/pterodactylus/sone/core/Options.java
new file mode 100644
index 0000000..04010da
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sone/core/Options.java
@@ -0,0 +1,181 @@
+package net.pterodactylus.sone.core;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Stores various options that influence Sone’s behaviour.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public class Options {
+
+	/**
+	 * Contains current and default value of an option.
+	 *
+	 * @param <T>
+	 *            The type of the option
+	 * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+	 */
+	public static interface Option<T> {
+
+		/**
+		 * Returns the default value of the option.
+		 *
+		 * @return The default value of the option
+		 */
+		public T getDefault();
+
+		/**
+		 * Returns the current value of the option. If the current value is not
+		 * set (usually {@code null}), the default value is returned.
+		 *
+		 * @return The current value of the option
+		 */
+		public T get();
+
+		/**
+		 * Returns the real value of the option. This will also return an unset
+		 * value (usually {@code null})!
+		 *
+		 * @return The real value of the option
+		 */
+		public T getReal();
+
+		/**
+		 * Sets the current value of the option.
+		 *
+		 * @param value
+		 *            The new value of the option
+		 */
+		public void set(T value);
+
+	}
+
+	/**
+	 * Interface for objects that want to be notified when an option changes its
+	 * value.
+	 *
+	 * @param <T>
+	 *            The type of the option
+	 * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+	 */
+	public static interface OptionWatcher<T> {
+
+		/**
+		 * Notifies an object that an option has been changed.
+		 *
+		 * @param option
+		 *            The option that has changed
+		 * @param oldValue
+		 *            The old value of the option
+		 * @param newValue
+		 *            The new value of the option
+		 */
+		public void optionChanged(Option<T> option, T oldValue, T newValue);
+
+	}
+
+	/**
+	 * Basic implementation of an {@link Option} that notifies an
+	 * {@link OptionWatcher} if the value changes.
+	 *
+	 * @param <T>
+	 *            The type of the option
+	 * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+	 */
+	public static class DefaultOption<T> implements Option<T> {
+
+		/** The default value. */
+		private final T defaultValue;
+
+		/** The current value. */
+		private T value;
+
+		/** The option watcher. */
+		private final OptionWatcher<T> optionWatcher;
+
+		/**
+		 * Creates a new default option.
+		 *
+		 * @param defaultValue
+		 *            The default value of the option
+		 * @param optionWatcher
+		 *            The option watcher
+		 */
+		public DefaultOption(T defaultValue, OptionWatcher<T> optionWatcher) {
+			this.defaultValue = defaultValue;
+			this.optionWatcher = optionWatcher;
+		}
+
+		/**
+		 * {@inheritDoc}
+		 */
+		@Override
+		public T getDefault() {
+			return defaultValue;
+		}
+
+		/**
+		 * {@inheritDoc}
+		 */
+		@Override
+		public T get() {
+			return (value != null) ? value : defaultValue;
+		}
+
+		/**
+		 * Returns the real value of the option. This will also return an unset
+		 * value (usually {@code null})!
+		 *
+		 * @return The real value of the option
+		 */
+		@Override
+		public T getReal() {
+			return value;
+		}
+
+		/**
+		 * {@inheritDoc}
+		 */
+		@Override
+		public void set(T value) {
+			T oldValue = this.value;
+			this.value = value;
+			if (!get().equals(oldValue)) {
+				optionWatcher.optionChanged(this, oldValue, get());
+			}
+		}
+
+	}
+
+	/** Holds all {@link Integer} {@link Option}s. */
+	private final Map<String, Option<Integer>> integerOptions = new HashMap<String, Option<Integer>>();
+
+	/**
+	 * Adds an {@link Integer} {@link Option}.
+	 *
+	 * @param name
+	 *            The name of the option
+	 * @param integerOption
+	 *            The option
+	 * @return The given option
+	 */
+	public Option<Integer> addIntegerOption(String name, Option<Integer> integerOption) {
+		integerOptions.put(name, integerOption);
+		return integerOption;
+	}
+
+	/**
+	 * Returns an {@link Integer} {@link Option}.
+	 *
+	 * @param name
+	 *            The name of the integer option to get
+	 * @return The integer option, or {@code null} if there is no option with
+	 *         the given name
+	 */
+	public Option<Integer> getIntegerOption(String name) {
+		return integerOptions.get(name);
+	}
+
+}