/*
* Copyright 2002-2012 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.xquery.support;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.io.Resource;
import org.springframework.integration.MessagingException;
import org.springframework.util.Assert;
/**
* The common utility class that is used to perform all common operations
* amongst XQuery modules. To contain all common operations that would be used
* by the router, transformer etc along with all the parsers for these components
*
* @author Amol Nayak
*
* @since 1.0
*
*/
public final class XQueryUtils {
private static final Log logger = LogFactory.getLog(XQueryUtils.class);
private XQueryUtils() {
//prevent instantiation
throw new AssertionError("Cannot instantiate a utility class");
}
/**
* Reads the XQuery string from the resource file specified
*
* @param resource the {@link Resource} instance of the file that contains the XQuery
* currently only classpath and file resources are supported
*
* @return the XQuery string from the resource specified
*/
public static String readXQueryFromResource(Resource resource) {
Assert.notNull(resource, "null resource provided");
Assert.isTrue(resource.exists(), "Provided XQuery resource does not exist");
Assert.isTrue(resource.isReadable(), "Provided XQuery resource is not readable");
BufferedReader reader = null;
try {
URL url = resource.getURL();
InputStream inStream = url.openStream();
reader = new BufferedReader(new InputStreamReader(inStream));
String line = reader.readLine();
StringBuilder builder = new StringBuilder();
while(line != null) {
builder.append(line).append("\n");
line = reader.readLine();
}
String xQuery = builder.toString();
reader.close();
return xQuery;
} catch (IOException e) {
throw new MessagingException("Error while reading the xQuery resource", e);
} finally {
if(reader != null) {
try {
reader.close();
} catch (IOException e) {
logger.error("Exception while closing reader", e);
}
}
}
}
}