Add builder for ScriptItemProcessor

resolves #BATCH-2616

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/builder/ScriptItemProcessorBuilder.java

@@ -0,0 +1,125 @@
+/*
+ * 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.support.builder;
+
+import org.springframework.batch.item.support.ScriptItemProcessor;
+import org.springframework.core.io.Resource;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * Creates a fully qualified ScriptItemProcessor.
+ *
+ * @author Glenn Renfro
+ *
+ * @since 4.0
+ */
+public class ScriptItemProcessorBuilder<I, O> {
+
+	private String language;
+
+	private Resource scriptResource;
+
+	private String scriptSource;
+
+	private String itemBindingVariableName;
+
+	/**
+	 * Sets the {@link org.springframework.core.io.Resource} location of the script to
+	 * use. The script language will be deduced from the filename extension.
+	 *
+	 * @param resource the {@link org.springframework.core.io.Resource} location of the
+	 * script to use.
+	 * @return this instance for method chaining
+	 * @see ScriptItemProcessor#setScript(Resource)
+	 * 
+	 */
+	public ScriptItemProcessorBuilder<I, O> scriptResource(Resource resource) {
+		this.scriptResource = resource;
+
+		return this;
+	}
+
+	/**
+	 * Establishes the language of the script.
+	 *
+	 * @param language the language of the script.
+	 * @return this instance for method chaining
+	 * @see ScriptItemProcessor#setScriptSource(String, String)
+	 */
+	public ScriptItemProcessorBuilder<I, O> language(String language) {
+		this.language = language;
+
+		return this;
+	}
+
+	/**
+	 * Sets the provided {@link String} as the script source code to use. Language must
+	 * not be null nor empty when using script.
+	 *
+	 * @param scriptSource the {@link String} form of the script source code to use.
+	 * @return this instance for method chaining
+	 * @see ScriptItemProcessor#setScriptSource(String, String)
+	 */
+	public ScriptItemProcessorBuilder<I, O> scriptSource(String scriptSource) {
+		this.scriptSource = scriptSource;
+
+		return this;
+	}
+
+	/**
+	 * Provides the ability to change the key name that scripts use to obtain the current
+	 * item to process if the variable represented by:
+	 * {@link ScriptItemProcessor#ITEM_BINDING_VARIABLE_NAME}
+	 * is not suitable ("item").
+	 *
+	 * @param itemBindingVariableName the desired binding variable name
+	 * @return this instance for method chaining
+	 * @see ScriptItemProcessor#setItemBindingVariableName(String)
+	 */
+	public ScriptItemProcessorBuilder<I, O> itemBindingVariableName(String itemBindingVariableName) {
+		this.itemBindingVariableName = itemBindingVariableName;
+
+		return this;
+	}
+
+	/**
+	 * Returns a fully constructed {@link ScriptItemProcessor}.
+	 *
+	 * @return a new {@link ScriptItemProcessor}
+	 */
+	public ScriptItemProcessor<I, O> build() {
+		if (this.scriptResource == null && !StringUtils.hasText(this.scriptSource)) {
+			throw new IllegalArgumentException("scriptResource or scriptSource is required.");
+		}
+		if (StringUtils.hasText(this.scriptSource)) {
+			Assert.hasText(this.language, "language is required when using scriptSource.");
+		}
+
+		ScriptItemProcessor<I, O> processor = new ScriptItemProcessor<>();
+		if (StringUtils.hasText(this.itemBindingVariableName)) {
+			processor.setItemBindingVariableName(this.itemBindingVariableName);
+		}
+		if (this.scriptResource != null) {
+			processor.setScript(this.scriptResource);
+		}
+		if (this.scriptSource != null) {
+			processor.setScriptSource(this.scriptSource, this.language);
+		}
+		return processor;
+	}
+}