Poll Directory for files
Hi
I'm new to Spring Integration and I've encountered few obstacles, I'm unable to resolve. I've gone thru latest spring ref. I didn't find solution particular to my solution requirement.
Requirement:
Poll a specified input directory periodically
Get list of files satisfying specified format (I've regular expr. to validate)
Sort the list of files based on file property like last modified timestamp
Here is the code/config I've followed to achive this.
My configuration file (config.xml):
================================================== ===============================================
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
..............................
">
<bean id="propertiesFile"
class="org.springframework.beans.factory.config.Pr opertyPlaceholderConfigurer">
<property name="locations">
<list>
<value>File.properties</value>
</list>
</property>
</bean>
<integration:service-activator
input-channel="inputChannel" output-channel="outChannel" ref="handler"
method="process" />
<file:inbound-channel-adapter id="inputChannel"
directory="file:${inputDir}" filter="filter"
scanner="myScanner">
<integrationoller id="poller" fixed-delay="${polling.interval}" />
</file:inbound-channel-adapter>
<file:outbound-channel-adapter id="outChannel"
delete-source-files="true" directory="${archiveDir}" />
<bean id="dirHandler" class="org.test.sample.poller.Handler">
<property name="scanner" ref="myScanner" />
<property name="inputDir" value="${inputDir}" />
<property name="job" ref="myJob" />
<property name="jobLauncher" ref="jobLauncher" />
</bean>
<bean id="filter"
class="org.springframework.integration.file.filter s.RegexPatternFileListFilter">
<constructor-arg value="${fileName.regex}" />
</bean>
<bean id="myScanner" class="org.test.sample.poller.myScanner"/>
<!-- <bean id="recursiveScanner" class="org.springframework.integration.file.Recurs iveLeafOnlyDirectoryScanner" /> -->
...................
...................
</bean>
================================================== ===============================================
The Handler Class call is :
-------------------------------------------------------------------------------------------------
public class Handler {
private MyScanner scanner;
private String inputDir;
public void processFile() {
List<File> listFiles = scanner.listFiles(new File(inputDir), String sortType);
// process my business logic of the list of files
}
public MyScanner getMyScanner() {
return scanner;
}
public void setMyScanner(MyScanner ffaFileSortScanner) {
this.scanner = scanner;
}
public String getInputDir() {
return inputDir;
}
public void setInputDir(String inputDir) {
this.inputDir = inputDir;
}
}
The MyScanner class is :
public class MyScanner extends RecursiveLeafOnlyDirectoryScanner implements DirectoryScanner {
MyScanner() {
super();
}
public File[] listEligibleFiles(String inputDir, String sortType) {
File[] listFiles = super.listEligibleFiles(new File(inputDir));
return sort(listEligibleFiles(new File(inputDir)), sortType);
}
private File[] sort(File[] inputDir, String sortType) {
if (sortType.equalsIgnoreCase("Asc")) {
sortFilesAsc(inputDir);
}
if (sortType.equalsIgnoreCase("Desc")) {
sortFilesDesc(inputDir);
}
return inputDir;
}
public void sortFilesDesc(File[] files) {
Arrays.sort(files, new Comparator<File>() {
public int compare(File o1, File o2) {
if (o1.lastModified() > o2.lastModified()) {
return -1;
} else if (o1.lastModified() < o2.lastModified()) {
return +1;
} else {
return 0;
}
}
});
}
public void sortFilesAsc(File[] files) {
Arrays.sort(files, new Comparator<File>() {
public int compare(File o1, File o2) {
if (o1.lastModified() < o2.lastModified()) {
return -1;
} else if (o1.lastModified() > o2.lastModified()) {
return +1;
} else {
return 0;
}
}
});
}
}
-------------------------------------------------------------------------------------------------
The application is run while calling new ClassPathXmlApplicationContext(<config.xml>) from a JobRunner java class.
The Handler class has process method should have the list of filtered files from the directory. The files in the input folder are filtered by RegexPatternFileListFilter at the in-bound channel adapter level. I've used a scanner (like RecursiveLeafOnlyDirectoryScanner) to get the list of files.
Questions:
1. The framework class RegexPatternFileListFilter expects constructor argument value. If I hard-code the regular expression then only this work. But, if I put like: <constructor-arg value="${fileName.regex}" /> as above. It doesnot return any files. If you see I've already define PropertyPlaceConfigurer to File.properties and fileName.regex is defined as well. My requirement is to read from a properties file only. Can you please help me how read the value from a properties file instead of hard-code it?
2. As my requirement is to get list of files of particular format from an input directory. Since, in-bound-channel adapter returns only one file at a time, so, I've to use a scanner to get a list of files. Also, I need sort the files based on file property like lastModified. Due to this, I've to write a custom scanner extending RecursiveLeafOnlyDirectoryScanner with additional functionality to return ordered(Asc/Desc) list of files. But I think this is duplication of responsibilty as scanner and handler both are configured in the inbound adapter, So, in the Handler bean we don't need to inject the scanner and inputDir again.
a) Is there any way to get the list of files in the Handler class from the in-bound-channel without need to inject inputDir and scanner in the Handler bean again?
It would be very helpfull if you provide the code snippet to achieve that.
b) The use of the custom scanner, MyScanner above gives me error:
--------------------------------------------------------
INFO : org.springframework.scheduling.concurrent.ThreadPo olTaskScheduler - Shutting down ExecutorService 'taskScheduler'
ERROR: org.test.sample.poller.JobRunner - Error in runJob method: Error creating bean with name 'org.springframework.integration.config.ServiceAct ivatorFactoryBean#0':
Cannot resolve reference to bean 'handler' while setting bean property 'targetObject'; nested exception is org.springframework.beans.factory.BeanCreationExce ption:
Error creating bean with name 'handler' defined in class path resource [config.xml]: Initialization of bean failed;
nested exception is org.springframework.beans.ConversionNotSupportedEx ception:
Failed to convert property value of type '$Proxy12 implementing org.springframework.integration.file.DirectoryScan ner,
org.springframework.aop.SpringProxy,org.springfram ework.aop.framework.Advised' to required type 'org.test.sample.poller.myScanner' for property 'scanner';
nested exception is java.lang.IllegalStateException: Cannot convert value of type [$Proxy12 implementing org.springframework.integration.file.DirectoryScan ner,
org.springframework.aop.SpringProxy,org.springfram ework.aop.framework.Advised] to required type [org.test.sample.poller.myScanner] for property 'scanner':
no matching editors or conversion strategy found java.lang.IllegalStateException:
Cannot convert value of type [$Proxy12 implementing org.springframework.integration.file.DirectoryScan ner,
org.springframework.aop.SpringProxy,org.springfram ework.aop.framework.Advised] to required type [org.test.sample.poller.myScanner] for property 'scanner':
no matching editors or conversion strategy found
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What is mistake I've done in writing the scanner? why the spring integration framework in-bound adapter is not recognizing it?
Any suggestion or better approach without required to change my requirement is also highly appreciated.
Appreciate your assistance.
Pankaj
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