add MultiReader and RegexFilterReaderTest, also tests MultiReader

src/main/java/org/cobbzilla/util/io/MultiReader.java

@@ -0,0 +1,47 @@
+package org.cobbzilla.util.io;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.util.ArrayList;
+import java.util.List;
+
+public class MultiReader extends Reader {
+
+    private final List<Reader> readers = new ArrayList<>();
+    private Reader currentReader;
+    private int readerIndex = 0;
+    private boolean endOfReaders = false;
+
+    public MultiReader (Reader r) {
+        addReader(r);
+        currentReader = r;
+    }
+
+    public void addReader (Reader r) {
+        synchronized (readers) {
+            readers.add(r);
+        }
+    }
+    public void addLastReader (Reader r) {
+        addReader(r);
+        endOfReaders = true;
+    }
+
+    @Override public int read(char[] buf, int off, int len) throws IOException {
+        int count = currentReader.read(buf, off, len);
+        if (count == -1) {
+            if (readerIndex == readers.size()-1) {
+                return endOfReaders ? -1 : 0;
+            }
+            currentReader.close();
+            readerIndex++;
+            currentReader = readers.get(readerIndex);
+            return read(buf, off, len);
+        }
+        return count;
+    }
+
+    @Override public void close() throws IOException {
+        if (currentReader != null) currentReader.close();
+    }
+}

src/test/java/org/cobbzilla/util/io/regex/RegexFilterReaderTest.java

@@ -0,0 +1,118 @@
+package org.cobbzilla.util.io.regex;
+
+import org.apache.commons.io.IOUtils;
+import org.cobbzilla.util.io.MultiReader;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.io.StringReader;
+import java.io.StringWriter;
+
+import static org.cobbzilla.util.daemon.ZillaRuntime.background;
+import static org.cobbzilla.util.daemon.ZillaRuntime.die;
+import static org.cobbzilla.util.system.Sleep.sleep;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+
+public class RegexFilterReaderTest {
+
+    public static final String TEST_STRING_1 = "this is a string\nand another string with a lone a near the end\nfoo.";
+    public static final String EXPECTED_STRING = "this is X string\nand another string with X lone X near the end\nfoo.";
+
+    @Test public void testSimpleRegexReader() throws Exception {
+        final Reader reader = new StringReader(TEST_STRING_1);
+        final RegexStreamFilter regexStreamFilter = new RegexReplacementFilter(" a ", 0, " X ");
+        final RegexFilterReader regexFilterReader = new RegexFilterReader(reader, 1024, regexStreamFilter);
+        final StringWriter result = new StringWriter();
+        IOUtils.copyLarge(regexFilterReader, result);
+        assertEquals("multi reader failed to get expected output", EXPECTED_STRING, result.toString());
+    }
+
+    @Test public void testSmallBufferRegexReader() throws Exception {
+        final Reader reader = new StringReader(TEST_STRING_1);
+        final RegexStreamFilter regexStreamFilter = new RegexReplacementFilter(" a ", 0, " X ");
+        final RegexFilterReader regexFilterReader = new RegexFilterReader(reader, 8, regexStreamFilter);
+        final StringWriter result = new StringWriter();
+        IOUtils.copyLarge(regexFilterReader, result);
+        assertEquals("multi reader failed to get expected output", EXPECTED_STRING, result.toString());
+    }
+
+    public static final String MULTI_TEST_STRING_1 = "this is a multi-stream test string\nthat should has a lot of stuff";
+    public static final String MULTI_TEST_STRING_2 = "in it but why should that matter?\nit is a bad thing to have multiple streams?";
+    public static final String MULTI_TEST_STRING_3 = "maybe some people think so\nbut a good person would never say that";
+
+    public static final String EXPECTED_MULTI_RESULT
+            = "this is X multi-stream test string\nthat should has X lot of stuff"
+            + "in it but why should that matter?\nit is X bad thing to have multiple streams?"
+            + "maybe some people think so\nbut X good person would never say that";
+
+    @Test public void testMultiStreamRegexReader() throws Exception {
+        final Reader reader1 = new StringReader(MULTI_TEST_STRING_1);
+        final Reader reader2 = new StringReader(MULTI_TEST_STRING_2);
+        final Reader reader3 = new StringReader(MULTI_TEST_STRING_3);
+        final MultiReader multiReader = new MultiReader(reader1);
+
+        final RegexStreamFilter regexStreamFilter = new RegexReplacementFilter(" a ", 0, " X ");
+        final RegexFilterReader regexFilterReader = new RegexFilterReader(multiReader, 8, regexStreamFilter);
+        final StringWriter result = new StringWriter();
+
+        final Thread t = background(() -> {
+            try {
+                IOUtils.copyLarge(regexFilterReader, result);
+            } catch (IOException e) {
+                die("Error copying in background: "+e, e);
+            }
+        });
+
+        sleep(500);
+        multiReader.addReader(reader2);
+        sleep(500);
+        multiReader.addLastReader(reader3);
+
+        t.join(1000);
+        assertFalse("Expected copy thread to finish", t.isAlive());
+        assertEquals("multi reader failed to get expected output", EXPECTED_MULTI_RESULT, result.toString());
+    }
+
+    public static final String MULTI2_TEST_STRING_1 = "this is a multi-stream barbecue string\nthat should has a lot of barbe";
+    public static final String MULTI2_TEST_STRING_2 = "cue stuff in it but why should that matter?\nit is a bad thing to barbecue multiple barbecues?";
+    public static final String MULTI2_TEST_STRING_3 = "maybe some people think so\nbut a good person would never say that about ba";
+    public static final String MULTI2_TEST_STRING_4 = "rbecues because barbecues are so totally awesome";
+
+    public static final String EXPECTED_MULTI_RESULT2
+            = "this is a multi-stream BBQ string\nthat should has a lot of BBQ "
+            + "stuff in it but why should that matter?\nit is a bad thing to BBQ multiple BBQs?"
+            + "maybe some people think so\nbut a good person would never say that about BBQs "
+            + "because BBQs are so totally awesome";
+
+    @Test public void testMultiStreamRegexReaderWithRegexAcrossBoundary() throws Exception {
+        final Reader reader1 = new StringReader(MULTI2_TEST_STRING_1);
+        final Reader reader2 = new StringReader(MULTI2_TEST_STRING_2);
+        final Reader reader3 = new StringReader(MULTI2_TEST_STRING_3);
+        final Reader reader4 = new StringReader(MULTI2_TEST_STRING_4);
+        final MultiReader multiReader = new MultiReader(reader1);
+
+        final RegexStreamFilter regexStreamFilter = new RegexReplacementFilter(" barbecue", 0, " BBQ");
+        final RegexFilterReader regexFilterReader = new RegexFilterReader(multiReader, 8, regexStreamFilter);
+        final StringWriter result = new StringWriter();
+
+        final Thread t = background(() -> {
+            try {
+                IOUtils.copyLarge(regexFilterReader, result);
+            } catch (IOException e) {
+                die("Error copying in background: "+e, e);
+            }
+        });
+
+        sleep(500);
+        multiReader.addReader(reader2);
+        sleep(500);
+        multiReader.addReader(reader3);
+        sleep(500);
+        multiReader.addLastReader(reader4);
+
+        t.join(1000);
+        assertFalse("Expected copy thread to finish", t.isAlive());
+        assertEquals("multi reader failed to get expected output", EXPECTED_MULTI_RESULT2, result.toString());
+    }}