com.github.ibole.infrastructure.common.properties.ConfigurationBuilder Maven / Gradle / Ivy
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package com.github.ibole.infrastructure.common.properties;
import org.codehaus.plexus.interpolation.EnvarBasedValueSource;
import org.codehaus.plexus.interpolation.Interpolator;
import org.codehaus.plexus.interpolation.MapBasedValueSource;
import org.codehaus.plexus.interpolation.StringSearchInterpolator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;
/*********************************************************************************************
* .
*
*
* Copyright 2016, iBole Inc. All rights reserved.
*
*********************************************************************************************/
public class ConfigurationBuilder {
protected final Logger log = LoggerFactory.getLogger(ConfigurationBuilder.class);
private final PropertyMap properties = new PropertyMap();
/**
* Add all properties from external Map.
*
* @param props the properties to add
* @return the instance of ConfigurationBuilder
*/
public ConfigurationBuilder properties(final Map props) {
if (props == null) {
throw new NullPointerException();
}
if (log.isDebugEnabled()) {
log.debug("Adding properties:");
for (Entry entry : props.entrySet()) {
log.debug(" {}='{}'", entry.getKey(), entry.getValue());
}
}
this.properties.putAll(props);
return this;
}
/**
* Add all properties from external URL.
*
* @param url the url to load
* @return the instance of ConfigurationBuilder
* @throws IOException exception when url is null
*/
public ConfigurationBuilder properties(final URL url) throws IOException {
if (url == null) {
throw new NullPointerException();
}
log.debug("Reading properties from: {}", url);
PropertyMap props = new PropertyMap();
props.load(url);
return properties(props);
}
public ConfigurationBuilder properties(final String resource, final boolean required)
throws IOException {
return properties(getClass(), resource, required);
}
/**
* @since 3.0
* @param clazz Class
* @param resource String
* @param required boolean
* @return the instance of ConfigurationBuilder
* @throws IOException IOException
*/
public ConfigurationBuilder properties(final Class clazz, final String resource,
final boolean required) throws IOException {
URL url = clazz.getResource(resource);
if (url == null) {
if (required) {
throw new IllegalStateException("Missing required resource: " + resource);
}
return this;
}
return properties(url);
}
/**
* Add all properties from external File.
* @param resource File
* @param required boolean
* @return the instance of ConfigurationBuilder
* @throws IOException IOException
*/
public ConfigurationBuilder properties(final File resource, final boolean required)
throws IOException {
if (resource == null || !resource.exists()) {
if (required) {
throw new IllegalStateException("Missing required resource: " + resource);
}
return this;
}
return properties(resource.toURI().toURL());
}
public ConfigurationBuilder defaults() throws IOException {
return properties("/default.properties", true);
}
/**
* Set the key/value to the properties.
*
* @param name the property key
* @param value the property value
* @return the the instance of ConfigurationBuilder
*/
public ConfigurationBuilder set(final String name, final String value) {
if (name == null) {
throw new NullPointerException();
}
if (value == null) {
throw new NullPointerException();
}
log.debug("Set: {}={}", name, value);
properties.put(name, value);
return this;
}
/**
* Provides customization of configuration.
*/
public interface Customizer {
void apply(ConfigurationBuilder builder) throws Exception;
}
/**
* custom configuration builder.
*
* @param customizer the Customizer
* @return ConfigurationBuilder
* @throws Exception exception when customizer is null
*/
public ConfigurationBuilder custom(final Customizer customizer) throws Exception {
if (customizer == null) {
throw new NullPointerException();
}
log.debug("Customizing: {}", customizer);
customizer.apply(this);
return this;
}
/**
* Override any existing properties with values from the given set of overrides.
* @param overrides Map
* @return ConfigurationBuilder
*/
public ConfigurationBuilder override(final Map overrides) {
if (overrides == null) {
throw new NullPointerException();
}
for (Entry entry : overrides.entrySet()) {
String name = entry.getKey();
if (properties.containsKey(name)) {
String value = entry.getValue();
log.debug("Override: {}={}", name, value);
properties.put(name, value);
}
}
return this;
}
/**
* Override existing properties by the specified properties.
* @see #override(Map)
* @param overrides Properties
* @return ConfigurationBuilder
*/
public ConfigurationBuilder override(final Properties overrides) {
return override(new PropertyMap(overrides));
}
/**
* Load external property file and override the existed properties. Normally the external file can
* be specified in system environment or JVM properties setting.
* @param name String
*/
private void loadExternalProperties(final String name) throws IOException {
String value = properties.get(name);
if (value == null) {
value = System.getProperty(JVMSystemProperties.EXTERNAL_CONFIG_PATH.getValue());
}
if (value == null) {
value = System.getenv(SystemEnvironmentVariables.EXTERNAL_CONFIG_PATH.getValue());
}
if (value == null) {
log.warn("Unable to load external properties null entry: {}", name);
return;
}
File file = new File(value).getCanonicalFile();
PropertyMap props = new PropertyMap();
props.load(file.toURI().toURL());
this.override(props);
properties.put(name, file.getPath());
}
/**
* underTest.set("foo", "bar"); underTest.set("baz", "${foo}"); assertThat(config.get("foo"),
* is("bar")); assertThat(config.get("baz"), is("bar"));
*
* @throws Exception Exception
*/
private void interpolate() throws Exception {
Interpolator interpolator = new StringSearchInterpolator();
interpolator.addValueSource(new MapBasedValueSource(properties));
interpolator.addValueSource(new MapBasedValueSource(System.getProperties()));
interpolator.addValueSource(new EnvarBasedValueSource());
for (Entry entry : properties.entrySet()) {
properties.put(entry.getKey(), interpolator.interpolate(entry.getValue()));
}
}
/**
* Build properties.
*
* @return the properties
* @throws Exception exception when not configured
*/
public Map build() throws Exception {
if (properties.isEmpty()) {
throw new IllegalStateException("Not configured");
}
loadExternalProperties("external.properties");
interpolate();
// return copy
PropertyMap props = new PropertyMap(properties);
log.info("Properties at the end:");
for (String key : props.keys()) {
log.info(" {}='{}'", key, props.get(key));
}
return props;
}
}