Add LangMap and tests

Author: idodeclare

opengrok-indexer/src/main/java/org/opengrok/indexer/analysis/LangMap.java

@@ -0,0 +1,89 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * See LICENSE.txt included in this distribution for the specific
+ * language governing permissions and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at LICENSE.txt.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2019, Chris Fraire <[email protected]>.
+ */
+
+package org.opengrok.indexer.analysis;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Represents an API for mapping file specifications versus languages and
+ * getting the ctags options representation (--langmap-&lt;LANG&gt; or
+ * --map-&lt;LANG&gt;) thereof.
+ */
+public interface LangMap {
+
+    /**
+     * Removes all settings from this map.
+     */
+    void clear();
+
+    /**
+     * Adds the specified mapping of a file specification to a language. Any
+     * matching exclusion via {@link #exclude(String)} is undone.
+     * @param fileSpec a value starting with a period ({@code '.'}) to specify
+     *                 a file extension; otherwise specifying a prefix.
+     * @throws IllegalArgumentException if {@code fileSpec} is {@code null} or
+     * is an extension (i.e. starting with a period) but contains any other
+     * periods, as that is not ctags-compatible
+     */
+    void add(String fileSpec, String ctagsLang);
+
+    /**
+     * Exclude the specified mapping of a file specification to any language.
+     * Any matching addition via {@link #add(String, String)} is undone.
+     * @throws IllegalArgumentException if {@code fileSpec} is {@code null}
+     */
+    void exclude(String fileSpec);
+
+    /**
+     * Gets the transformation of the instance's mappings to ctags arguments.
+     */
+    List<String> getCtagsArgs();
+
+    /**
+     * Creates a new instance, merging the settings from the current instance
+     * overlaying a specified {@code other}. Additions from the current instance
+     * take precedence, and exclusions from the {@code other} only take effect
+     * if the current instance has no matching addition.
+     * @param other a defined instance
+     * @return a defined instance
+     */
+    LangMap mergeSecondary(LangMap other);
+
+    /**
+     * Gets an unmodifiable view of the current instance.
+     */
+    LangMap unmodifiable();
+
+    /**
+     * Gets an unmodifiable view of the current additions.
+     */
+    Map<String, String> getAdditions();
+
+    /**
+     * Gets an unmodifiable view of the current exclusions.
+     */
+    Set<String> getExclusions();
+}