refaractor(api/filesystems): move FileInputIterator implementation to commons-fs

This commits adds the new interfaces FileInputIteratorFactory and Storage
in order to decouple iterator from the underlying file-system

Author: fhussonnois

connect-file-pulse-api/src/main/java/io/streamthoughts/kafka/connect/filepulse/internal/StringUtils.java

@@ -39,6 +39,10 @@ public static boolean isFastSplit(final String regex) {
     }
 
     public static boolean isNotBlank(final String string) {
-        return !(Objects.isNull(string) || string.isBlank());
+        return !isBlank(string);
+    }
+
+    public static boolean isBlank(final String string) {
+        return Objects.isNull(string) || string.isBlank();
     }
 }

connect-file-pulse-api/src/main/java/io/streamthoughts/kafka/connect/filepulse/reader/FileInputIteratorFactory.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2019-2021 StreamThoughts.
+ *
+ * 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 io.streamthoughts.kafka.connect.filepulse.reader;
+
+import io.streamthoughts.kafka.connect.filepulse.data.TypedStruct;
+import io.streamthoughts.kafka.connect.filepulse.source.FileRecord;
+
+import java.net.URI;
+
+/**
+ * A {@code FileInputIteratorFactory} can be used to get a new {@link FileInputIterator}.
+ */
+public interface FileInputIteratorFactory {
+
+    /**
+     * Creates a new {@link FileInputIterator} for the given object file.
+     *
+     * @param objectURI         the {@link URI} of the object file.
+     * @return                  a new {@link FileInputIterator}.
+     */
+    FileInputIterator<FileRecord<TypedStruct>> newIterator(final URI objectURI);
+}

connect-file-pulse-api/src/main/java/io/streamthoughts/kafka/connect/filepulse/reader/FileInputReader.java

@@ -19,9 +19,8 @@
 package io.streamthoughts.kafka.connect.filepulse.reader;
 
 import io.streamthoughts.kafka.connect.filepulse.data.TypedStruct;
-import io.streamthoughts.kafka.connect.filepulse.source.FileContext;
-import io.streamthoughts.kafka.connect.filepulse.source.FileRecord;
 import io.streamthoughts.kafka.connect.filepulse.source.FileObjectMeta;
+import io.streamthoughts.kafka.connect.filepulse.source.FileRecord;
 import org.apache.kafka.common.Configurable;
 
 import java.net.URI;
@@ -30,7 +29,7 @@
 /**
  * A {@code FileInputReader} is the principal class used to read an input file/object.
  */
-public interface FileInputReader extends Configurable, AutoCloseable {
+public interface FileInputReader extends FileInputIteratorFactory, Configurable, AutoCloseable {
 
     /**
      * Configure this class with the given key-value pairs.
@@ -45,27 +44,27 @@ default void configure(final Map<String, ?> configs) {
     /**
      * Gets the metadata for the source object identified by the given {@link URI}.
      *
-     * @param sourceURI   the {@link URI} of the source object.
+     * @param objectURI   the {@link URI} of the file object.
      * @return            a new {@link FileObjectMeta} instance.
      */
-    FileObjectMeta readMetadata(final URI sourceURI);
+    FileObjectMeta getObjectMetadata(final URI objectURI);
 
     /**
      * Checks whether the source object identified by the given {@link URI} can be read.
      *
-     * @param sourceURI   the {@link URI} of the source object.
+     * @param objectURI   the {@link URI} of the file object.
      * @return            the {@code true}.
      */
-    boolean isReadable(final URI sourceURI);
+    boolean canBeRead(final URI objectURI);
 
     /**
-     * Creates a new {@link FileInputIterator} instance.
+     * Creates a new {@link FileInputIterator} for the given {@link URI}.
      *
-     * @param context   the context of the file on which to create the iterator.
+     * @param objectURI   the {@link URI} of the file object.
      * @return          a new {@link FileInputIterator} iterator instance.
      *
      */
-    FileInputIterator<FileRecord<TypedStruct>> newIterator(final FileContext context);
+    FileInputIterator<FileRecord<TypedStruct>> newIterator(final URI objectURI);
 
     /**
      * Close this reader and any remaining un-close iterators.

connect-file-pulse-api/src/main/java/io/streamthoughts/kafka/connect/filepulse/source/DelegateFileInputIterator.java

@@ -0,0 +1,158 @@
+/*
+ * Copyright 2019-2020 StreamThoughts.
+ *
+ * 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 io.streamthoughts.kafka.connect.filepulse.source;
+
+import io.streamthoughts.kafka.connect.filepulse.data.TypedStruct;
+import io.streamthoughts.kafka.connect.filepulse.reader.FileInputIterator;
+import io.streamthoughts.kafka.connect.filepulse.reader.FileInputReader;
+import io.streamthoughts.kafka.connect.filepulse.reader.RecordsIterable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.net.URI;
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * {@code DelegateFileInputIterator}.
+ */
+public class DelegateFileInputIterator implements FileInputIterator<FileRecord<TypedStruct>> {
+
+    private static final Logger LOG = LoggerFactory.getLogger(DelegateFileInputIterator.class);
+
+    private final URI objectURI;
+    private final FileInputReader reader;
+    private final AtomicBoolean isClosed = new AtomicBoolean(false);
+
+    private FileInputIterator<FileRecord<TypedStruct>> iterator;
+
+    /**
+     * Creates a new {@link DelegateFileInputIterator} instance.
+     *
+     * @param objectURI the input source file.
+     * @param reader    the input source reader used to create a new {@link FileInputIterator}.
+     */
+    DelegateFileInputIterator(final URI objectURI, final FileInputReader reader) {
+        this.objectURI = Objects.requireNonNull(objectURI, "source can't be null");
+        this.reader = Objects.requireNonNull(reader, "reader can't be null");
+    }
+
+    /**
+     * Gets the metadata of the backed object file.
+     *
+     * @return  the {@link FileObjectMeta}
+     */
+    public FileObjectMeta getMetadata() {
+        return reader.getObjectMetadata(objectURI);
+    }
+
+    /**
+     * Gets the URI of the backed object file.
+     *
+     * @return  the {@link URI}
+     */
+    public URI getObjectURI() {
+        return objectURI;
+    }
+
+    /**
+     * Gets the {@link FileInputIterator} or create a new one if none has been initialized yet.
+     */
+    public void open() {
+        if (isOpen()) throw new IllegalStateException("Iterator is already open");
+        LOG.info("Opening new iterator for: {}", objectURI);
+        iterator = reader.newIterator(objectURI);
+    }
+
+    /**
+     * @return {@code true} if an iterator is already opened.
+     */
+    boolean isOpen() {
+        return iterator != null && !iterator.isClose();
+    }
+
+    /**
+     *
+     * @return {@code true} if the backed object file can be read and is accessible.
+     */
+    boolean isValid() {
+        return reader.canBeRead(objectURI);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public FileContext context() {
+        checkIsOpen();
+        return iterator.context();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void seekTo(final FileObjectOffset offset) {
+        checkIsOpen();
+        iterator.seekTo(offset);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public RecordsIterable<FileRecord<TypedStruct>> next() {
+        checkIsOpen();
+        return iterator.next();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean hasNext() {
+        checkIsOpen();
+        return iterator.hasNext();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void close() {
+        if (!isClosed.get()) {
+            LOG.info("Closing iterator for: {} ", iterator.context().metadata());
+            iterator.close();
+            isClosed.set(true);
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean isClose() {
+        return isClosed.get();
+    }
+
+    private void checkIsOpen() {
+        if (!isOpen()) throw new IllegalStateException("This iterator is not initialized yet or already closed");
+    }
+
+}

connect-file-pulse-api/src/main/java/io/streamthoughts/kafka/connect/filepulse/source/FileInputIterable.java

@@ -53,13 +53,13 @@ default String stringURI() {
      * @return the content-length of the source object.
      */
     @JsonProperty("contentLength")
-    long contentLength();
+    Long contentLength();
 
     /**
      * @return the creation date or the last modified date, whichever is the latest.
      */
     @JsonProperty("lastModified")
-    long lastModified();
+    Long lastModified();
 
     /**
      * @return the digest of the source object content.