copy 'springy' branch to heritrix3

commons/src/main/java/org/archive/io/GenerationFileHandler.java

@@ -0,0 +1,136 @@
+/*
+ *  This file is part of the Heritrix web crawler (crawler.archive.org).
+ *
+ *  Licensed to the Internet Archive (IA) by one or more individual 
+ *  contributors. 
+ *
+ *  The IA 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.archive.io;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.logging.FileHandler;
+
+import org.archive.util.FileUtils;
+
+
+/**
+ * FileHandler with support for rotating the current file to
+ * an archival name with a specified integer suffix, and
+ * provision of a new replacement FileHandler with the current
+ * filename.
+ *
+ * @author gojomo
+ */
+public class GenerationFileHandler extends FileHandler {
+    private LinkedList<String> filenameSeries = new LinkedList<String>();
+    private boolean shouldManifest = false;
+
+    /**
+     * @return Returns the filenameSeries.
+     */
+    public List<String> getFilenameSeries() {
+        return filenameSeries;
+    }
+
+    /**
+     * Constructor.
+     * @param pattern
+     * @param append
+     * @param shouldManifest
+     * @throws IOException
+     * @throws SecurityException
+     */
+    public GenerationFileHandler(String pattern, boolean append,
+            boolean shouldManifest)
+    throws IOException, SecurityException {
+        super(pattern, append);
+        filenameSeries.addFirst(pattern);
+        this.shouldManifest = shouldManifest;
+    }
+
+    /**
+     * @param filenameSeries
+     * @param shouldManifest
+     * @throws IOException
+     */
+    public GenerationFileHandler(LinkedList<String> filenameSeries,
+            boolean shouldManifest)
+    throws IOException {
+        super((String)filenameSeries.getFirst(), false); // Never append in this case
+        this.filenameSeries = filenameSeries;
+        this.shouldManifest = shouldManifest;
+    }
+
+    /**
+     * Move the current file to a new filename with the storeSuffix in place
+     * of the activeSuffix; continuing logging to a new file under the
+     * original filename.
+     *
+     * @param storeSuffix Suffix to put in place of <code>activeSuffix</code>
+     * @param activeSuffix Suffix to replace with <code>storeSuffix</code>.
+     * @return GenerationFileHandler instance.
+     * @throws IOException
+     */
+    public GenerationFileHandler rotate(String storeSuffix,
+            String activeSuffix)
+    throws IOException {
+        close();
+        String filename = (String)filenameSeries.getFirst();
+        if (!filename.endsWith(activeSuffix)) {
+            throw new FileNotFoundException("Active file does not have" +
+                " expected suffix");
+        }
+        String storeFilename = filename.substring(0,
+             filename.length() - activeSuffix.length()) +
+             storeSuffix;
+        File activeFile = new File(filename);
+        File storeFile = new File(storeFilename);
+        if (!activeFile.renameTo(storeFile)) {
+            throw new IOException("Unable to move " + filename + " to " +
+                storeFilename);
+        }
+        filenameSeries.add(1, storeFilename);
+        GenerationFileHandler newGfh = 
+            new GenerationFileHandler(filenameSeries, shouldManifest);
+        newGfh.setFormatter(this.getFormatter());
+        return newGfh;
+    }
+    
+    /**
+     * @return True if should manifest.
+     */
+    public boolean shouldManifest() {
+        return this.shouldManifest;
+    }
+
+    /**
+     * Constructor-helper that rather than clobbering any existing 
+     * file, moves it aside with a timestamp suffix. 
+     * 
+     * @param filename
+     * @param append
+     * @param shouldManifest
+     * @return
+     * @throws SecurityException
+     * @throws IOException
+     */
+    public static GenerationFileHandler makeNew(String filename, boolean append, boolean shouldManifest) throws SecurityException, IOException {
+        FileUtils.moveAsideIfExists(new File(filename));
+        return new GenerationFileHandler(filename, append, shouldManifest);
+    }
+}