Java: Add 'EnvironmentConfiguredTracer'

Adding 'ppaml_tracer_init_from_env' (commit b9dfb8d0) makes the Java
code substantially more complicated, as it introduces a second mechanism
to construct 'Tracer's.  While I could simply provide two constructors
in the 'Tracer' class, this would make for an ugly and dangerous
implementation; after all, the life cycle of a tracer configured
explicitly is noticeably different from the life cycle of a tracer
configured by sourcing environment variables.  Instead, I’ve changed
'Tracer' to be an interface implemented by 'ExplicitlyConfiguredTracer'
and 'EnvironmentConfiguredTracer'.

This is an API-breaking change.

1 files changed, 34 insertions, 0 deletions

diff --git a/bindings/java/src/java/com/galois/ppaml/tracer/UndefinedTracerBasePathException.java b/bindings/java/src/java/com/galois/ppaml/tracer/UndefinedTracerBasePathException.java
new file mode 100644
index 0000000..1a67826
--- /dev/null
+++ b/bindings/java/src/java/com/galois/ppaml/tracer/UndefinedTracerBasePathException.java
@@ -0,0 +1,34 @@
+/* UndefinedTracerBasePathException -- no tracer path specified
+ * Copyright (C) 2014  Galois, Inc.
+ *
+ * This library 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 3 of the License, or (at your option)
+ * any later version.
+ *
+ * This library 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 library.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * To contact Galois, complete the Web form at
+ * <http://corp.galois.com/contact/> or write to Galois, Inc., 421 Southwest
+ * 6th Avenue, Suite 300, Portland, Oregon, 97204-1622. */
+
+package com.galois.ppaml.tracer;
+
+/**
+ * Indicates that a tracer attempted to initialize with an undefined path.
+ */
+public class UndefinedTracerBasePathException extends ConfigurationException {
+
+    static final long serialVersionUID = 8041122764340259905L;
+
+    protected UndefinedTracerBasePathException() {
+        super("attempted to configure tracer with undefined base path");
+    }
+
+}