Add Smart Quotes canonicizer

src/com/jgaap/canonicizers/SmartQuotes.java

@@ -0,0 +1,74 @@
+/*
+ * JGAAP -- a graphical program for stylometric authorship attribution
+ * Copyright (C) 2009,2011 by Patrick Juola
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.jgaap.canonicizers;
+
+import com.jgaap.generics.Canonicizer;
+
+/**
+ * Replaces Unicode smart/curly quotes with plain ASCII equivalents so that
+ * typographic and straight quotes are treated identically during feature
+ * extraction.
+ */
+public class SmartQuotes extends Canonicizer {
+
+	@Override
+	public String displayName() {
+		return "Smart Quotes";
+	}
+
+	@Override
+	public String tooltipText() {
+		return "Replace Unicode smart/curly quotes with plain ASCII quote characters.";
+	}
+
+	@Override
+	public boolean showInGUI() {
+		return true;
+	}
+
+	@Override
+	public char[] process(char[] procText) {
+		StringBuilder sb = new StringBuilder(procText.length);
+		for (char c : procText) {
+			switch (c) {
+				case '‘': // ' left single quotation mark
+				case '’': // ' right single quotation mark
+				case '‛': // ‛ single high-reversed-9 quotation mark
+				case '′': // ′ prime
+					sb.append('\'');
+					break;
+				case '“': // " left double quotation mark
+				case '”': // " right double quotation mark
+				case '„': // „ double low-9 quotation mark
+				case '‟': // ‟ double high-reversed-9 quotation mark
+				case '″': // ″ double prime
+				case '«': // « left-pointing double angle quotation mark
+				case '»': // » right-pointing double angle quotation mark
+					sb.append('"');
+					break;
+				case '‹': // ‹ single left-pointing angle quotation mark
+				case '›': // › single right-pointing angle quotation mark
+					sb.append('\'');
+					break;
+				default:
+					sb.append(c);
+			}
+		}
+		return sb.toString().toCharArray();
+	}
+}

unittests/com/jgaap/canonicizers/SmartQuotesTest.java

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+package com.jgaap.canonicizers;
+
+import static org.junit.Assert.*;
+
+import java.util.Arrays;
+
+import org.junit.Test;
+
+public class SmartQuotesTest {
+
+	@Test
+	public void testProcess() {
+		SmartQuotes canon = new SmartQuotes();
+
+		// Curly single quotes → '
+		assertTrue(Arrays.equals(new char[]{'\''},
+				canon.process(new char[]{'‘'})));
+		assertTrue(Arrays.equals(new char[]{'\''},
+				canon.process(new char[]{'’'})));
+
+		// Curly double quotes → "
+		assertTrue(Arrays.equals(new char[]{'"'},
+				canon.process(new char[]{'“'})));
+		assertTrue(Arrays.equals(new char[]{'"'},
+				canon.process(new char[]{'”'})));
+
+		// Double low-9 quotation mark → "
+		assertTrue(Arrays.equals(new char[]{'"'},
+				canon.process(new char[]{'„'})));
+
+		// Angle quotation marks → "
+		assertTrue(Arrays.equals(new char[]{'"'},
+				canon.process(new char[]{'«'})));
+		assertTrue(Arrays.equals(new char[]{'"'},
+				canon.process(new char[]{'»'})));
+
+		// Plain ASCII characters pass through unchanged
+		String plain = "Hello, \"world\"! It's fine.";
+		assertTrue(Arrays.equals(plain.toCharArray(),
+				canon.process(plain.toCharArray())));
+
+		// Mixed smart and plain text
+		String input   = "“Hello” ‘world’";
+		String expected = "\"Hello\" 'world'";
+		assertTrue(Arrays.equals(expected.toCharArray(),
+				canon.process(input.toCharArray())));
+	}
+}