org.sqlproc.engine.SqlFilesLoader Maven / Gradle / Ivy
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package org.sqlproc.engine;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The helper class for the file(s) loading. The file(s) can be located on the classpath, in the root directory or in
* the user's home directory. It's used for the purpose of the {@link SqlProcessorLoader} instance creation.
*
*
* For more info please see the Tutorials.
*
* @author Vladimir Hudec
*/
public class SqlFilesLoader {
/**
* The internal slf4j logger.
*/
protected final Logger logger = LoggerFactory.getLogger(getClass());
/**
* The string representation of the file(s) content.
*/
private StringBuilder sbStatements;
/**
* Reads the file(s) content and creates a new SqlFilesLoader instance.
*
* @param fileName
* The name of the file to be read.
* @param loaderClass
* Class used to detect the correct classloader.
*/
public SqlFilesLoader(String fileName, Class loaderClass) {
sbStatements = load(fileName, loaderClass);
}
/**
* Reads the file(s) content and creates a new SqlFilesLoader instance.
*
* @param fileName
* The name of the file to be read.
* @param loaderClass
* Class used to detect the correct classloader.
* @return the content of the specified file(s) as a String
*/
public static StringBuilder getStatements(Class loaderClass, String fileName) {
SqlFilesLoader loader = new SqlFilesLoader(fileName, loaderClass);
return loader.getStatements();
}
/**
* Reads the file(s) content and creates a new SqlFilesLoader instance.
*
* @param fileNames
* The names of the files to be read.
* @param loaderClass
* Class used to detect the correct classloader.
*/
public SqlFilesLoader(List fileNames, Class loaderClass) {
sbStatements = new StringBuilder();
if (fileNames == null || fileNames.isEmpty())
return;
for (String fileName : fileNames) {
StringBuilder statements = load(fileName, loaderClass);
sbStatements.append(statements);
}
}
/**
* Reads the file(s) content and creates a new SqlFilesLoader instance.
*
* @param fileNames
* The name sof the files to be read.
* @param loaderClass
* Class used to detect the correct classloader.
* @return the content of the specified file(s) as a String
*/
public static StringBuilder getStatements(Class loaderClass, String... fileNames) {
ArrayList propsNames = new ArrayList();
Collections.addAll(propsNames, fileNames);
SqlFilesLoader loader = new SqlFilesLoader(propsNames, loaderClass);
return loader.getStatements();
}
/**
* Reads the file content and creates a String representation of this content.
*
* @param fileName
* The name of the file to be read.
* @param loaderClass
* Class used to detect the correct classloader.
* @return the content of the specified file as a String
*/
private StringBuilder load(String fileName, Class loaderClass) {
if (logger.isTraceEnabled()) {
logger.trace(">> load, fileName=" + fileName + ", loaderClass=" + loaderClass);
}
StringBuilder statements = new StringBuilder();
try {
String configFile = "/" + fileName;
InputStream is = loaderClass.getResourceAsStream(configFile);
if (is == null) {
configFile = fileName;
is = loaderClass.getResourceAsStream(configFile);
}
if (is == null) {
try {
configFile = "/" + fileName;
is = new FileInputStream(configFile);
} catch (FileNotFoundException e) {
}
}
if (is == null) {
try {
configFile = System.getProperty("user.home") + configFile;
is = new FileInputStream(configFile);
} catch (FileNotFoundException e) {
}
}
if (is != null) {
try {
BufferedReader input = new BufferedReader(new InputStreamReader(is));
String line = null;
/*
* readLine is a bit quirky : it returns the content of a line MINUS the newline. it returns null
* only for the END of the stream. it returns an empty String if two newlines appear in a row.
*/
while ((line = input.readLine()) != null) {
statements.append(line);
statements.append(System.getProperty("line.separator"));
}
} catch (IOException ioe) {
} finally {
try {
is.close();
} catch (IOException ignore) {
}
}
}
return statements;
} finally {
if (logger.isTraceEnabled()) {
logger.trace("<< load, properties=" + statements);
}
}
}
/**
* Returns the content of all read files.
*
* @return the content of all read files
*/
public StringBuilder getStatements() {
return sbStatements;
}
/**
* Returns a string representation of the object.
*
* @return a string representation of the object
*/
@Override
public String toString() {
StringBuilder sb = new StringBuilder("Statements: ");
sb.append(sbStatements);
return sb.toString();
}
}