io.joshworks.snappy.maven.tools.DefaultLaunchScript Maven / Gradle / Ivy
/*
* Copyright 2012-2015 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 io.joshworks.snappy.maven.tools;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.Charset;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Default implementation of {@link LaunchScript}. Provides the default Spring Boot launch
* script or can load a specific script File. Also support mustache style template
* expansion of the form {{name:default}}.
*
* @author Phillip Webb
* @since 1.3.0
*/
public class DefaultLaunchScript implements LaunchScript {
private static final Charset UTF_8 = Charset.forName("UTF-8");
private static final int BUFFER_SIZE = 4096;
private static final Pattern PLACEHOLDER_PATTERN = Pattern
.compile("\\{\\{(\\w+)(:.*?)?\\}\\}");
private final String content;
/**
* Create a new {@link DefaultLaunchScript} instance.
*
* @param file the source script file or {@code null} to use the default
* @param properties an optional set of script properties used for variable expansion
* @throws IOException if the script cannot be loaded
*/
public DefaultLaunchScript(File file, Map properties) throws IOException {
String content = loadContent(file);
this.content = expandPlaceholders(content, properties);
}
private String loadContent(File file) throws IOException {
if (file == null) {
return loadContent(getClass().getResourceAsStream("launch.script"));
}
return loadContent(new FileInputStream(file));
}
private String loadContent(InputStream inputStream) throws IOException {
try {
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
copy(inputStream, outputStream);
return new String(outputStream.toByteArray(), UTF_8);
} finally {
inputStream.close();
}
}
private void copy(InputStream inputStream, OutputStream outputStream)
throws IOException {
byte[] buffer = new byte[BUFFER_SIZE];
int bytesRead = -1;
while ((bytesRead = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
}
outputStream.flush();
}
private String expandPlaceholders(String content, Map properties) {
StringBuffer expanded = new StringBuffer();
Matcher matcher = PLACEHOLDER_PATTERN.matcher(content);
while (matcher.find()) {
String name = matcher.group(1);
String value = matcher.group(2);
if (properties != null && properties.containsKey(name)) {
value = (String) properties.get(name);
} else {
value = (value == null ? matcher.group(0) : value.substring(1));
}
matcher.appendReplacement(expanded, value);
}
matcher.appendTail(expanded);
return expanded.toString();
}
@Override
public byte[] toByteArray() {
return this.content.getBytes(UTF_8);
}
}