BATCH-1033: Created PrefixMatchingCompositeLineMapper and reorganized PrefixMatchingCompositeLineTokenizer so that its lookup functionality could be reused. Also updated the multiRecordType sample by removing PrefixMatchingCompositeFieldSetMapper in favor of the new class.

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/mapping/PrefixMatchingCompositeLineMapper.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2006-2007 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.file.mapping;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.springframework.batch.item.file.transform.LineTokenizer;
+import org.springframework.batch.item.file.transform.PrefixMatchingCompositeLineTokenizer;
+import org.springframework.util.Assert;
+
+/**
+ * <p>
+ * A {@link LineMapper} implementation that stores a mapping of String prefixes
+ * to delegate {@link LineTokenizer}s as well as a mapping of String prefixes
+ * to delegate {@link LineTokenizer}s. Each line received will be tokenized and
+ * then mapped to a field set.
+ * 
+ * <p>
+ * Both the tokenizing and the mapping work in a similar way. The line will be
+ * checked for its prefix. If the prefix matches a key in the map of delegates,
+ * then the corresponding delegate will be used. Otherwise, the default
+ * tokenizer or mapper will be used. The default can be configured in the
+ * delegate map by setting its corresponding prefix to the empty string.
+ * 
+ * @author Dan Garrette
+ */
+public class PrefixMatchingCompositeLineMapper<T> extends PrefixMatchingCompositeLineTokenizer implements LineMapper<T> {
+
+	private Map<String, FieldSetMapper<T>> fieldSetMappers = null;
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see org.springframework.batch.item.file.mapping.LineMapper#mapLine(java.lang.String,
+	 *      int)
+	 */
+	public T mapLine(String line, int lineNumber) throws Exception {
+		return this.matchPrefix(line, this.fieldSetMappers).mapFieldSet(this.tokenize(line));
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
+	 */
+	public void afterPropertiesSet() throws Exception {
+		super.afterPropertiesSet();
+		Assert.isTrue(this.fieldSetMappers != null && this.fieldSetMappers.size() > 0,
+				"The 'fieldSetMappers' property must be non-empty");
+	}
+
+	public void setFieldSetMappers(Map<String, FieldSetMapper<T>> fieldSetMappers) {
+		this.fieldSetMappers = new LinkedHashMap<String, FieldSetMapper<T>>(fieldSetMappers);
+	}
+}

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/PrefixMatchingCompositeLineTokenizer.java

@@ -16,10 +16,11 @@
 
 package org.springframework.batch.item.file.transform;
 
-import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.util.Assert;
 
 /**
  * A {@link LineTokenizer} implementation that stores a mapping of String
@@ -30,46 +31,69 @@ import java.util.Map;
  * {@link LineTokenizer} can be configured in the delegate map by setting its
  * corresponding prefix to the empty string.
  * 
+ * @author Dan Garrette
  */
-public class PrefixMatchingCompositeLineTokenizer implements LineTokenizer {
+public class PrefixMatchingCompositeLineTokenizer implements LineTokenizer, InitializingBean {
 
-	private Map<String, LineTokenizer> tokenizers = new HashMap<String, LineTokenizer>();
+	private Map<String, LineTokenizer> tokenizers = null;
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see org.springframework.batch.item.file.transform.LineTokenizer#tokenize(java.lang.String)
+	 */
+	public FieldSet tokenize(String line) {
+		return this.matchPrefix(line, this.tokenizers).tokenize(line);
+	}
+
+	/**
+	 * @param line
+	 * @return the delegate whose prefix matches the given line
+	 */
+	protected <S> S matchPrefix(String line, Map<String, S> delegates) {
+		S delegate = null;
+		S defaultDelegate = null;
+
+		if (line != null) {
+			for (String key : delegates.keySet()) {
+				if ("".equals(key)) {
+					defaultDelegate = delegates.get(key);
+					// don't break here or the delegate may not be found
+				}
+				else if (line.startsWith(key)) {
+					delegate = delegates.get(key);
+					break;
+				}
+			}
+
+			if (delegate == null) {
+				delegate = defaultDelegate;
+			}
+		}
+		else if (delegates.containsKey(null)) {
+			delegate = delegates.get(null);
+		}
+		else {
+			throw new IllegalStateException("Could not handle a null line");
+		}
+
+		if (delegate == null) {
+			throw new IllegalStateException("Could not find a matching prefix for line=[" + line + "]");
+		}
+		return delegate;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
+	 */
+	public void afterPropertiesSet() throws Exception {
+		Assert.isTrue(this.tokenizers != null && this.tokenizers.size() > 0,
+				"The 'tokenizers' property must be non-empty");
+	}
 
 	public void setTokenizers(Map<String, LineTokenizer> tokenizers) {
 		this.tokenizers = new LinkedHashMap<String, LineTokenizer>(tokenizers);
 	}
-
-	public FieldSet tokenize(String line) {
-
-		if (line == null) {
-			return new DefaultFieldSet(new String[0]);
-		}
-
-		LineTokenizer tokenizer = null;
-		LineTokenizer defaultTokenizer = null;
-
-		for (String key : tokenizers.keySet()) {
-
-			if ("".equals(key)) {
-				defaultTokenizer = (LineTokenizer) tokenizers.get(key);
-				// don't break here or the tokenizer may not be found
-				continue;
-			}
-			if (line.startsWith(key)) {
-				tokenizer = (LineTokenizer) tokenizers.get(key);
-				break;
-			}
-		}
-
-		if (tokenizer == null) {
-			tokenizer = defaultTokenizer;
-		}
-
-		if (tokenizer == null) {
-			throw new IllegalStateException("Could not match record to tokenizer for line=[" + line + "]");
-		}
-
-		return tokenizer.tokenize(line);
-	}
-
 }