SynchronizedMutable; Mutables utility class

#3188

de.metas.util/src/main/java/org/adempiere/util/lang/Mutables.java

@@ -0,0 +1,44 @@
+package org.adempiere.util.lang;
+
+import lombok.experimental.UtilityClass;
+
+/*
+ * #%L
+ * de.metas.util
+ * %%
+ * Copyright (C) 2017 metas GmbH
+ * %%
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, either version 2 of the
+ * License, or (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public
+ * License along with this program. If not, see
+ * <http://www.gnu.org/licenses/gpl-2.0.html>.
+ * #L%
+ */
+
+@UtilityClass
+public class Mutables
+{
+	public static <T> IMutable<T> of(final T value)
+	{
+		return new Mutable<>(value);
+	}
+
+	public static <T> SynchronizedMutable<T> synchronizedMutable()
+	{
+		return SynchronizedMutable.of(null);
+	}
+
+	public static <T> SynchronizedMutable<T> synchronizedMutable(final T value)
+	{
+		return SynchronizedMutable.of(value);
+	}
+}

de.metas.util/src/main/java/org/adempiere/util/lang/SynchronizedMutable.java

@@ -0,0 +1,83 @@
+package org.adempiere.util.lang;
+
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+import lombok.NonNull;
+
+/*
+ * #%L
+ * de.metas.util
+ * %%
+ * Copyright (C) 2017 metas GmbH
+ * %%
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program. If not, see
+ * <http://www.gnu.org/licenses/gpl-2.0.html>.
+ * #L%
+ */
+
+public final class SynchronizedMutable<T> implements IMutable<T>
+{
+	public static <T> SynchronizedMutable<T> of(final T value)
+	{
+		return new SynchronizedMutable<>(value);
+	}
+
+	private T value;
+
+	private SynchronizedMutable(final T value)
+	{
+		this.value = value;
+	}
+
+	@Override
+	public synchronized T getValue()
+	{
+		return value;
+	}
+
+	@Override
+	public synchronized void setValue(final T value)
+	{
+		this.value = value;
+	}
+
+	@Override
+	public synchronized T compute(@NonNull final Function<T, T> remappingFunction)
+	{
+		this.value = remappingFunction.apply(this.value);
+		return this.value;
+	}
+
+	public synchronized T computeIfNull(@NonNull final Supplier<T> supplier)
+	{
+		if (value == null)
+		{
+			this.value = supplier.get();
+		}
+
+		return this.value;
+	}
+
+	public synchronized T computeIfNotNull(@NonNull final Function<T, T> remappingFunction)
+	{
+		if (value != null)
+		{
+			this.value = remappingFunction.apply(this.value);
+		}
+
+		return this.value;
+	}
+
+}