[IO-318] Add Charset sister APIs to method that take a String charset name.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/io/trunk@1307568 13f79535-47bb-0310-9956-ffa450edef68

Author: garydgregory

src/main/java/org/apache/commons/io/Charsets.java

@@ -26,14 +26,17 @@
  * @since 2.3
  */
 public class Charsets {
+    //
+    // This class should only contain Charset instances for required encodings. This guarantees that it will load correctly and
+    // without delay on all Java platforms.
+    //
 
     /**
      * Returns the given Charset or the default Charset if the given Charset is null. 
      * 
      * @param charset
      *            A charset or null.
      * @return the given Charset or the default Charset if the given Charset is null
-     * @since 2.3
      */
     public static Charset toCharset(Charset charset) {
         return charset == null ? Charset.defaultCharset() : charset;
@@ -47,10 +50,79 @@ public static Charset toCharset(Charset charset) {
      * @return a Charset for the named charset
      * @throws UnsupportedCharsetException
      *             If the named charset is unavailable
-     * @since 2.3
      */
     public static Charset toCharset(String charset) {
         return charset == null ? Charset.defaultCharset() : Charset.forName(charset);
     }
 
+    /**
+     * CharEncodingISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1. </p>
+     * <p>
+     * Every implementation of the Java platform is required to support this character encoding.
+     * </p>
+     * 
+     * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
+     */
+    public static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
+
+    /**
+     * <p>
+     * Seven-bit ASCII, also known as ISO646-US, also known as the Basic Latin block of the Unicode character set.
+     * </p>
+     * <p>
+     * Every implementation of the Java platform is required to support this character encoding.
+     * </p>
+     * 
+     * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
+     */
+    public static final Charset US_ASCII = Charset.forName("US-ASCII");
+
+    /**
+     * <p>
+     * Sixteen-bit Unicode Transformation Format, The byte order specified by a mandatory initial byte-order mark
+     * (either order accepted on input, big-endian used on output)
+     * </p>
+     * <p>
+     * Every implementation of the Java platform is required to support this character encoding.
+     * </p>
+     * 
+     * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
+     */
+    public static final Charset UTF_16 = Charset.forName("UTF-16");
+
+    /**
+     * <p>
+     * Sixteen-bit Unicode Transformation Format, big-endian byte order.
+     * </p>
+     * <p>
+     * Every implementation of the Java platform is required to support this character encoding.
+     * </p>
+     * 
+     * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
+     */
+    public static final Charset UTF_16BE = Charset.forName("UTF-16BE");
+
+    /**
+     * <p>
+     * Sixteen-bit Unicode Transformation Format, little-endian byte order.
+     * </p>
+     * <p>
+     * Every implementation of the Java platform is required to support this character encoding.
+     * </p>
+     * 
+     * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
+     */
+    public static final Charset UTF_16LE = Charset.forName("UTF-16LE");
+
+    /**
+     * <p>
+     * Eight-bit Unicode Transformation Format.
+     * </p>
+     * <p>
+     * Every implementation of the Java platform is required to support this character encoding.
+     * </p>
+     * 
+     * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
+     */
+    public static final Charset UTF_8 = Charset.forName("UTF-8");
 }

src/test/java/org/apache/commons/io/CharsetsTestCase.java

@@ -0,0 +1,71 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.io;
+
+import java.nio.charset.Charset;
+
+import junit.framework.Assert;
+
+import org.junit.Test;
+
+/**
+ * Tests {@link Charsets}.
+ * 
+ * @version $Id: CharEncodingTest.java 1298985 2012-03-09 19:12:49Z ggregory $
+ */
+public class CharsetsTestCase {
+
+    @Test
+    public void testToCharset() {
+        Assert.assertEquals(Charset.defaultCharset(), Charsets.toCharset((String) null));
+        Assert.assertEquals(Charset.defaultCharset(), Charsets.toCharset((Charset) null));
+        Assert.assertEquals(Charset.defaultCharset(), Charsets.toCharset(Charset.defaultCharset()));
+        Assert.assertEquals(Charset.forName("UTF-8"), Charsets.toCharset(Charset.forName("UTF-8")));
+    }
+    
+    @Test
+    public void testIso8859_1() {
+        Assert.assertEquals("ISO-8859-1", Charsets.ISO_8859_1.name());
+    }
+
+    @Test
+    public void testUsAscii() {
+        Assert.assertEquals("US-ASCII", Charsets.US_ASCII.name());
+    }
+
+    @Test
+    public void testUtf16() {
+        Assert.assertEquals("UTF-16", Charsets.UTF_16.name());
+    }
+
+    @Test
+    public void testUtf16Be() {
+        Assert.assertEquals("UTF-16BE", Charsets.UTF_16BE.name());
+    }
+
+    @Test
+    public void testUtf16Le() {
+        Assert.assertEquals("UTF-16LE", Charsets.UTF_16LE.name());
+    }
+
+    @Test
+    public void testUtf8() {
+        Assert.assertEquals("UTF-8", Charsets.UTF_8.name());
+    }
+
+}

src/test/java/org/apache/commons/io/IOUtilsTestCase.java

@@ -46,8 +46,6 @@
 import org.apache.commons.io.testtools.FileBasedTestCase;
 import org.junit.Assert;
 
-// Note: jdk1.2 dependency
-
 /**
  * This is used to test IOUtils for correctness. The following checks are performed:
  * <ul>
@@ -291,12 +289,6 @@ public void testToByteArray_Reader() throws IOException {
         Assert.assertArrayEquals(expecteds, actuals);
     }
 
-    public void testToCharset() {
-        Assert.assertEquals(Charset.defaultCharset(), Charsets.toCharset((String) null));
-        Assert.assertEquals(Charset.defaultCharset(), Charsets.toCharset((Charset) null));
-        Assert.assertEquals(Charset.defaultCharset(), Charsets.toCharset(Charset.defaultCharset()));
-        Assert.assertEquals(Charset.forName("UTF-8"), Charsets.toCharset(Charset.forName("UTF-8")));
-    }
     public void testInputStreamToByteArray() throws Exception {
         FileInputStream fin = new FileInputStream(m_testFile);
         try {