small cleanups; documented the code

[chaz/vimcoder] / src / com / dogcows / Util.java

diff --git a/src/com/dogcows/Util.java b/src/com/dogcows/Util.java
new file mode 100644 (file)
index 0000000..bc5bdb8
--- /dev/null
+++ b/src/com/dogcows/Util.java
@@ -0,0 +1,158 @@
+
+package com.dogcows;
+
+import java.io.*;
+import java.util.Arrays;
+import java.util.Map;
+
+/**
+ * @author Charles McGarvey
+ * The TopCoder Arena editor plug-in providing support for Vim.
+ * 
+ * Distributable under the terms and conditions of the 2-clause BSD license;
+ * see the file COPYING for a complete text of the license.
+ */
+public abstract class Util
+{
+    /**
+     * Concatenate two arrays into a single array.
+     * @param a First array.
+     * @param b Second array.
+     * @return The combined array.
+     */
+    public static <T> T[] concat(T[] a, T[] b)
+    {
+        T[] result = Arrays.copyOf(a, a.length + b.length);
+        System.arraycopy(b, 0, result, a.length, b.length);
+        return result;
+    }
+    
+    /**
+     * Combined string elements from two arrays into a single array, gluing
+     * together elements of the same index with a delimiter string.
+     * @param a First string array.
+     * @param b Second string array.
+     * @param glue The delimiter string.
+     * @return The combined array.
+     */
+    public static String[] combine(String[] a, String[] b, String glue)
+    {
+        String[] result = new String[Math.min(a.length, b.length)];
+        for (int i = 0; i < result.length; ++i)
+        {
+            result[i] = a[i] + glue + b[i];
+        }
+        return result;
+    }
+
+    /**
+     * Join the elements of a string array with a delimiter.
+     * @param a The array.
+     * @param glue The delimiter string.
+     * @return The joined string.
+     */
+    public static String join(String[] a, String glue)
+    {
+        if (a.length == 0) return "";
+        StringBuilder result = new StringBuilder();
+        result.append(a[0]);
+        for (int i = 1; i < a.length; ++i) result.append(glue).append(a[i]);
+        return result.toString();
+    }
+    
+    /**
+     * Quote a string by replacing prepending backslashes and double
+     * quotation characters with an extra backslash.
+     * @param The string to be quoted.
+     * @return The quoted string.
+     */
+    public static String quote(String a)
+    {
+        a = a.replaceAll("\\\\", "\\\\\\\\");
+        a = a.replaceAll("\"",   "\\\\\\\"");
+        return a;
+    }
+    
+    /**
+     * Simply read a file's contents into a string object.
+     * @param file The file to read.
+     * @return The contents of the file.
+     * @throws IOException If the file is not readable.
+     */
+    public static String readFile(File file) throws IOException
+    {
+        StringBuilder text = new StringBuilder();
+    
+        BufferedReader reader = new BufferedReader(new FileReader(file.getPath()));
+        try
+        {
+            String line = null;
+            
+            while ((line = reader.readLine()) != null)
+            {
+                text.append(line + System.getProperty("line.separator"));
+            }
+        }
+        finally
+        {
+            reader.close();
+        }
+    
+        return text.toString();
+    }
+    
+    /**
+     * Read a resource file into a string object.  The resources should be
+     * placed in the directory `resources' underneath the parent directory of
+     * this class.  Reading resources packaged in a jar is allowable.
+     * @param path Relative path to the resource.
+     * @return The contents of the resource.
+     * @throws IOException If the resource is not readable.
+     */
+    public static String readResource(String path) throws IOException
+    {
+        StringBuilder text = new StringBuilder();
+        
+        InputStream stream = Util.class.getResourceAsStream("resources/" + path);
+        if (stream != null)
+        {
+            try
+            {
+                byte[]  buffer = new byte[4096];
+                int     numBytes = 0;
+                while (0 < (numBytes = stream.read(buffer)))
+                {
+                    text.append(new String(buffer, 0, numBytes));
+                }
+            }
+            finally
+            {
+                stream.close();
+            }
+        }
+        
+        return text.toString();
+    }
+    
+    /**
+     * The poor man's template package.  Provide a template and a map of terms
+     * to build the result with the terms expanded into the template.  Terms
+     * in the template should appear surrounded with dollar signs.  For example,
+     * if $MYTERM$ appears in the template, it will be replaced by the value
+     * into the terms map with the key MYTERM (if it exists in the map).
+     * @param template The template string.
+     * @param terms A map of key/value terms.
+     * @return The string expanded from the template and terms.
+     */
+    public static String expandTemplate(String template, Map<String,String> terms)
+    {
+        String text = template;
+        for (String key : terms.keySet())
+        {
+            text = text.replaceAll("\\$" + key + "\\$",
+                                   Util.quote(terms.get(key)));
+        }
+        return text;
+    }
+}
+