X-Git-Url: https://git.argeo.org/?a=blobdiff_plain;f=org.argeo.api.uuid%2Fsrc%2Forg%2Fargeo%2Fapi%2Fuuid%2FUuidHolder.java;fp=org.argeo.api.uuid%2Fsrc%2Forg%2Fargeo%2Fapi%2Fuuid%2FUuidHolder.java;h=253f0ad923842e78d1196b2268e7a2fe0963eb85;hb=e8e2c65f356b30b35e4d8a1de66691a789c183bb;hp=0000000000000000000000000000000000000000;hpb=5b33b0f7a92debf285b31d308add6470a31894a9;p=lgpl%2Fargeo-commons.git

diff --git a/org.argeo.api.uuid/src/org/argeo/api/uuid/UuidHolder.java b/org.argeo.api.uuid/src/org/argeo/api/uuid/UuidHolder.java
new file mode 100644
index 000000000..253f0ad92
--- /dev/null
+++ b/org.argeo.api.uuid/src/org/argeo/api/uuid/UuidHolder.java
@@ -0,0 +1,71 @@
+package org.argeo.api.uuid;
+
+import java.io.Serializable;
+import java.util.Objects;
+import java.util.UUID;
+import java.util.function.Supplier;
+
+/**
+ * An immutable wrapper for an {@link UUID}, which can be used as a base for a
+ * derivation hierarchy, while strongly enforcing semantic equality with the
+ * underlying {@link UUID}. It is therefore immutable, and all base methods are
+ * directly and trivially based on {@link UUID} methods; they do represent the
+ * same unique "thing" (be it an entity, a point in time, etc.), consistently
+ * with the fundamental concept of uuid.
+ */
+public class UuidHolder implements Supplier<UUID>, Serializable {
+	private static final long serialVersionUID = APM.SERIAL;
+
+	/**
+	 * The wrapped {@link UUID}. Protected rather than private, since it is
+	 * immutable and a {@link UUID} is itself immutable.
+	 */
+	protected final UUID uuid;
+
+	/**
+	 * Constructs a new {@link UuidHolder} based on this uuid.
+	 * 
+	 * @param uuid the UUID to wrap, cannot be null.
+	 * @throws NullPointerException if the provided uuid is null.
+	 */
+	protected UuidHolder(UUID uuid) {
+		Objects.requireNonNull(uuid, "UUID cannot be null");
+		this.uuid = uuid;
+	}
+
+	/** The wrapped {@link UUID}. */
+	public final UUID getUuid() {
+		return uuid;
+	}
+
+	/** The wrapped {@link UUID}. */
+	@Override
+	public final UUID get() {
+		return getUuid();
+	}
+
+	/** Calls {@link UUID#hashCode()} on the wrapped {@link UUID}. */
+	@Override
+	public final int hashCode() {
+		return uuid.hashCode();
+	}
+
+	/**
+	 * Equals only with non-null {@link UuidHolder} if and only if their wrapped
+	 * uuid are equals by calling {@link UUID#equals(Object)}.
+	 */
+	@Override
+	public final boolean equals(Object obj) {
+		if (obj == null || !(obj instanceof UuidHolder))
+			return false;
+		UuidHolder typedUuid = (UuidHolder) obj;
+		return uuid.equals(typedUuid.uuid);
+	}
+
+	/** Calls {@link UUID#toString()} on the wrapped {@link UUID}. */
+	@Override
+	public final String toString() {
+		return uuid.toString();
+	}
+
+}