INT-664 Added a FileListFilterFactoryBean to create the filter based on the combined settings of a custom filter reference, a filename pattern, and the boolean preventDuplicates flag.

org.springframework.integration.file/src/main/java/org/springframework/integration/file/config/FileListFilterFactoryBean.java

@@ -0,0 +1,122 @@
+/*
+ * Copyright 2002-2009 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.integration.file.config;
+
+import java.io.File;
+import java.util.regex.Pattern;
+
+import org.springframework.beans.factory.FactoryBean;
+import org.springframework.integration.file.AbstractFileListFilter;
+import org.springframework.integration.file.AcceptOnceFileListFilter;
+import org.springframework.integration.file.CompositeFileListFilter;
+import org.springframework.integration.file.FileListFilter;
+import org.springframework.integration.file.PatternMatchingFileListFilter;
+
+/**
+ * @author Mark Fisher
+ * @since 1.0.3
+ */
+public class FileListFilterFactoryBean implements FactoryBean {
+
+	private volatile FileListFilter fileListFilter;
+
+	private volatile FileListFilter filterReference;
+
+	private volatile Pattern filenamePattern;
+
+	private volatile Boolean preventDuplicates;
+
+	private final Object monitor = new Object();
+
+
+	public void setFilterReference(FileListFilter filterReference) {
+		this.filterReference = filterReference;
+	}
+
+	public void setFilenamePattern(Pattern filenamePattern) {
+		this.filenamePattern = filenamePattern;
+	}
+
+	public void setPreventDuplicates(Boolean preventDuplicates) {
+		this.preventDuplicates = preventDuplicates;
+	}
+
+	public Object getObject() throws Exception {
+		if (this.fileListFilter == null) {
+			synchronized (this.monitor) {
+				this.intializeFileListFilter();
+			}
+		}
+		return this.fileListFilter;
+	}
+
+	public Class<?> getObjectType() {
+		return (this.fileListFilter != null)
+			? this.fileListFilter.getClass() : FileListFilter.class;
+	}
+
+	public boolean isSingleton() {
+		return true;
+	}
+
+	private void intializeFileListFilter() {
+		if (this.fileListFilter != null) {
+			return;
+		}
+		FileListFilter flf = null;
+		if (this.filterReference != null && this.filenamePattern != null) {
+			throw new IllegalArgumentException("The 'filter' reference and " +
+					"'filename-pattern' attributes are mutually exclusive.");
+		}
+		if (this.filterReference != null) {
+			if (Boolean.TRUE.equals(this.preventDuplicates)) {
+				flf = this.createCompositeWithAcceptOnceFilter(this.filterReference);
+			}
+			else { // preventDuplicates is either FALSE or NULL 
+				flf = this.filterReference; 
+			}
+		}
+		else if (this.filenamePattern != null) {
+			PatternMatchingFileListFilter patternFilter = new PatternMatchingFileListFilter(this.filenamePattern);
+			if (Boolean.FALSE.equals(this.preventDuplicates)) {
+				flf = patternFilter;
+			}
+			else { // preventDuplicates is either TRUE or NULL
+				flf = this.createCompositeWithAcceptOnceFilter(patternFilter);
+			}
+		}
+		else if (Boolean.FALSE.equals(this.preventDuplicates)) {
+			flf = new AbstractFileListFilter() {
+				@Override
+				protected boolean accept(File file) {
+					return true;
+				}
+			};
+		}
+		else { // preventDuplicates is either TRUE or NULL
+			flf = new AcceptOnceFileListFilter();
+		}
+		this.fileListFilter = flf;
+	}
+
+	private FileListFilter createCompositeWithAcceptOnceFilter(FileListFilter otherFilter) {
+		CompositeFileListFilter compositeFilter = new CompositeFileListFilter();
+		compositeFilter.addFilter(new AcceptOnceFileListFilter(), otherFilter);
+		return compositeFilter;
+	}
+
+}