Refactor Prefs to PrefService

Using a static utility method for Prefs is limiting - it provides no way
to override preference saving/loading behavior. This creates problems
when there are errors or negative interactions with the Preferences
implementation - for example, in MATLAB there are known bugs regarding
the Java Preferences implementation.

By converting to a PrefService we can now control this behavior more
precisely, as needed. The Prefs utility class will remain for now, but
will delegate to the PrefService when it has been created - allowing the
utility method behavior to be overridden similarly.

Author: hinerm

src/main/java/org/scijava/preferences/AbstractPrefService.java

@@ -0,0 +1,58 @@
+/*
+ * #%L
+ * SciJava Common shared library for SciJava software.
+ * %%
+ * Copyright (C) 2009 - 2014 Board of Regents of the University of
+ * Wisconsin-Madison, Broad Institute of MIT and Harvard, and Max Planck
+ * Institute of Molecular Cell Biology and Genetics.
+ * %%
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ * #L%
+ */
+
+package org.scijava.preferences;
+
+import org.scijava.service.AbstractService;
+import org.scijava.util.Prefs;
+
+/**
+ * Abstract {@link PrefService} implementation. Provides a basic
+ * {@link #setStaticBehavior()} implementation, calling it during service
+ * {@link #initialize()} to set this as the delegate service.
+ *
+ * @author Mark Hiner
+ */
+public abstract class AbstractPrefService extends AbstractService implements
+	PrefService
+{
+
+	@Override
+	public void initialize() {
+		setStaticBehavior();
+	}
+
+	@Override
+	public void setStaticBehavior() {
+		Prefs.setDelegateService(this);
+	}
+
+}