Add Builder for MappingLdifReader.

Resolves #BATCH-2601

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/ldif/builder/MappingLdifReaderBuilder.java

@@ -0,0 +1,200 @@
+/*
+ * Copyright 2017 the original author or authors.
+ *
+ *  Licensed 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.springframework.batch.item.ldif.builder;
+
+import org.springframework.batch.item.ldif.MappingLdifReader;
+import org.springframework.batch.item.ldif.RecordCallbackHandler;
+import org.springframework.batch.item.ldif.RecordMapper;
+import org.springframework.core.io.Resource;
+import org.springframework.util.Assert;
+
+/**
+ * Creates a fully qualified MappingLdifReader.
+ *
+ * @author Glenn Renfro
+ *
+ * @since 4.0
+ */
+public class MappingLdifReaderBuilder<T>  {
+	private Resource resource;
+
+	private int recordsToSkip = 0;
+
+	private boolean strict = true;
+
+	private RecordCallbackHandler skippedRecordsCallback;
+
+	private RecordMapper<T> recordMapper;
+
+	private boolean saveState = true;
+
+	private String name;
+
+	private int maxItemCount = Integer.MAX_VALUE;
+
+	private int currentItemCount;
+
+	/**
+	 * Configure if the state of the {@link org.springframework.batch.item.ItemStreamSupport}
+	 * should be persisted within the {@link org.springframework.batch.item.ExecutionContext}
+	 * for restart purposes.
+	 *
+	 * @param saveState defaults to true
+	 * @return The current instance of the builder.
+	 */
+	public MappingLdifReaderBuilder<T> saveState(boolean saveState) {
+		this.saveState = saveState;
+
+		return this;
+	}
+
+	/**
+	 * The name used to calculate the key within the
+	 * {@link org.springframework.batch.item.ExecutionContext}. Required if
+	 * {@link #saveState(boolean)} is set to true.
+	 *
+	 * @param name name of the reader instance
+	 * @return The current instance of the builder.
+	 * @see org.springframework.batch.item.ItemStreamSupport#setName(String)
+	 */
+	public MappingLdifReaderBuilder<T> name(String name) {
+		this.name = name;
+
+		return this;
+	}
+
+	/**
+	 * Configure the max number of items to be read.
+	 *
+	 * @param maxItemCount the max items to be read
+	 * @return The current instance of the builder.
+	 * @see org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader#setMaxItemCount(int)
+	 */
+	public MappingLdifReaderBuilder<T> maxItemCount(int maxItemCount) {
+		this.maxItemCount = maxItemCount;
+
+		return this;
+	}
+
+	/**
+	 * Index for the current item. Used on restarts to indicate where to start from.
+	 *
+	 * @param currentItemCount current index
+	 * @return this instance for method chaining
+	 * @see org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader#setCurrentItemCount(int)
+	 */
+	public MappingLdifReaderBuilder<T> currentItemCount(int currentItemCount) {
+		this.currentItemCount = currentItemCount;
+
+		return this;
+	}
+
+	/**
+	 * In strict mode the reader will throw an exception on
+	 * {@link MappingLdifReader#open(org.springframework.batch.item.ExecutionContext)} if
+	 * the input resource does not exist.
+	 *
+	 * @param strict true by default
+	 * @return this instance for method chaining.
+	 * @see MappingLdifReader#setStrict(boolean)
+	 */
+	public MappingLdifReaderBuilder<T> strict(boolean strict) {
+		this.strict = strict;
+
+		return this;
+	}
+
+	/**
+	 * {@link RecordCallbackHandler RecordCallbackHandler} implementations can be used to
+	 * take action on skipped records.
+	 *
+	 * @param skippedRecordsCallback will be called for each one of the initial skipped
+	 * lines before any items are read.
+	 * @return this instance for method chaining.
+	 * @see MappingLdifReader#setSkippedRecordsCallback(RecordCallbackHandler)
+	 */
+	public MappingLdifReaderBuilder<T> skippedRecordsCallback(RecordCallbackHandler skippedRecordsCallback) {
+		this.skippedRecordsCallback = skippedRecordsCallback;
+
+		return this;
+	}
+
+	/**
+	 * Public setter for the number of lines to skip at the start of a file. Can be used
+	 * if the file contains a header without useful (column name) information, and without
+	 * a comment delimiter at the beginning of the lines.
+	 *
+	 * @param recordsToSkip the number of lines to skip
+	 * @return this instance for method chaining.
+	 * @see MappingLdifReader#setRecordsToSkip(int)
+	 */
+	public MappingLdifReaderBuilder<T> recordsToSkip(int recordsToSkip) {
+		this.recordsToSkip = recordsToSkip;
+
+		return this;
+	}
+
+	/**
+	 * Establishes the resource that will be used as the input for the MappingLdifReader.
+	 *
+	 * @param resource the resource that will be read.
+	 * @return this instance for method chaining.
+	 * @see MappingLdifReader#setResource(Resource)
+	 */
+	public MappingLdifReaderBuilder<T> resource(Resource resource) {
+		this.resource = resource;
+
+		return this;
+	}
+
+	/**
+	 * Setter for object mapper. This property is required to be set.
+	 * @param recordMapper maps record to an object
+	 */
+	public MappingLdifReaderBuilder<T> recordMapper(RecordMapper<T> recordMapper) {
+		this.recordMapper = recordMapper;
+
+		return this;
+	}
+
+	/**
+	 * Returns a fully constructed {@link MappingLdifReader}.
+	 *
+	 * @return a new {@link org.springframework.batch.item.ldif.MappingLdifReader}
+	 */
+	public MappingLdifReader<T> build() {
+		Assert.notNull(this.resource, "Resource is required.");
+		Assert.notNull(this.recordMapper, "RecordMapper is required.");
+		if (this.saveState) {
+			Assert.hasText(this.name, "A name is required when saveState is set to true");
+		}
+		MappingLdifReader<T> reader = new MappingLdifReader<>();
+		reader.setResource(this.resource);
+		reader.setRecordsToSkip(this.recordsToSkip);
+		reader.setSaveState(saveState);
+		reader.setCurrentItemCount(this.currentItemCount);
+		reader.setMaxItemCount(this.maxItemCount);
+		reader.setRecordMapper(this.recordMapper);
+		reader.setName(this.name);
+		if (this.skippedRecordsCallback != null) {
+			reader.setSkippedRecordsCallback(this.skippedRecordsCallback);
+		}
+		reader.setStrict(this.strict);
+
+		return reader;
+	}
+}