com.bluecatcode.common.io.Resources Maven / Gradle / Ivy
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package com.bluecatcode.common.io;
import com.google.common.base.Objects;
import com.google.common.io.LineProcessor;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.net.URLDecoder;
import java.nio.charset.Charset;
import java.util.Properties;
import static com.bluecatcode.common.contract.Checks.checkNotEmpty;
import static com.bluecatcode.common.contract.Postconditions.ensure;
import static com.bluecatcode.common.predicates.Predicates.isNotNull;
import static com.google.common.base.Charsets.UTF_8;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.io.Resources.readLines;
/**
* Provides utility methods for working with resources in the classpath.
*
* @see com.google.common.io.Resources
*/
public final class Resources {
private Resources() {
throw new UnsupportedOperationException();
}
/**
* @param loader the class loader to use
* @param resourceName the resource name
* @return the loaded content
* @see com.google.common.io.Resources#getResource(Class, String)
* @see com.google.common.io.Resources#toString(java.net.URL, java.nio.charset.Charset)
*/
public static String getResourceAsString(ClassLoader loader, String resourceName) {
checkArgument(loader != null, "Expected non-null class loader");
checkNotEmpty(resourceName);
URL url = loader.getResource(resourceName);
ensure(url, isNotNull(), "Expected non-null url for resourceName '%s'", resourceName);
return toString(url, UTF_8);
}
/**
* @param contextClass the class the resource is relative to
* @param resourceName the resource name
* @return the loaded content
* @throws IllegalArgumentException if the resource is not found
* @throws IllegalStateException if an I/O error occurs
* @see com.google.common.io.Resources#getResource(Class, String)
* @see com.google.common.io.Resources#toString(java.net.URL, java.nio.charset.Charset)
*/
public static String getResourceAsString(Class contextClass, String resourceName) {
checkArgument(contextClass != null, "Expected non-null contextClass");
checkNotEmpty(resourceName);
URL url = getResource(contextClass, resourceName);
return toString(url, UTF_8);
}
/**
* @param contextClass the class the resource is relative to
* @param resourceName the resource name
* @param lineProcessor the line processor to use
* @param the type of object to load into
* @return the loaded object of type T
* @see com.google.common.io.LineProcessor
* @see com.google.common.io.Resources#getResource(String)
* @see com.google.common.io.Resources#readLines(java.net.URL, java.nio.charset.Charset, LineProcessor)
*/
public static T getResourceWith(Class contextClass, String resourceName, LineProcessor lineProcessor) {
checkArgument(contextClass != null, "Expected non-null contextClass");
checkNotEmpty(resourceName);
checkArgument(lineProcessor != null, "Expected non-null lineProcessor");
URL url = getResource(contextClass, resourceName);
try {
return readLines(url, UTF_8, lineProcessor);
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/**
* @param url the URL to read from
* @param charset the charset to use
* @return the content
* @throws IllegalStateException if an I/O error occurs
* @see com.google.common.io.Resources#toString(java.net.URL, java.nio.charset.Charset)
*/
public static String toString(URL url, Charset charset) {
try {
return com.google.common.io.Resources.toString(checkNotNull(url), checkNotNull(charset));
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/**
* @param loader the class loader to use
* @param resourceName the resource name
* @return the file path
* @see com.google.common.io.Resources#getResource(String)
* @see java.net.URLDecoder#decode(String, String)
*/
public static String getResourceAsFilePath(ClassLoader loader, String resourceName) {
try {
return URLDecoder.decode(getResource(loader, resourceName).getFile(), UTF_8.toString());
} catch (UnsupportedEncodingException e) {
throw new IllegalArgumentException(e);
}
}
/**
* @param contextClass the class the resource is relative to
* @param resourceName the resource name
* @return the file path
* @see com.google.common.io.Resources#getResource(String)
* @see java.net.URLDecoder#decode(String, String)
*/
public static String getResourceAsFilePath(Class contextClass, String resourceName) {
try {
return URLDecoder.decode(getResource(contextClass, resourceName).getFile(), UTF_8.toString());
} catch (UnsupportedEncodingException e) {
throw new IllegalArgumentException(e);
}
}
/**
* @param contextClass the class the resource is relative to
* @param resourceName the resource name
* @return the loaded properties
*/
public static Properties getResourceAsProperties(Class contextClass, String resourceName) {
try (InputStream stream = getResourceAsStream(contextClass, resourceName)) {
Properties properties = new Properties();
properties.load(stream);
ensure(properties, isNotNull(), "Can't find %s on classpath for %s", resourceName, contextClass);
return properties;
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/**
* @param contextClass the class the resource is relative to
* @param resourceName the resource name
* @return the input stream
*/
public static InputStream getResourceAsStream(Class contextClass, String resourceName) {
checkArgument(contextClass != null, "Expected non-null contextClass");
checkNotEmpty(resourceName);
URL url = getResource(contextClass, resourceName);
try {
return url.openStream();
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
/**
* @param contextClass the class the resource is relative to
* @param resourceName the resource name
* @return the URL
* @see com.google.common.io.Resources#getResource(Class, String)
*/
public static URL getResource(Class contextClass, String resourceName) {
return com.google.common.io.Resources.getResource(contextClass, resourceName);
}
/**
* @param loader the class loader to use
* @param resourceName the resource name
* @return the input stream
*/
public static URL getResource(ClassLoader loader, String resourceName) {
URL url = loader.getResource(resourceName);
checkArgument(url != null, "resource %s not found.", resourceName);
return url;
}
/**
* Returns current thread context class loader or {@link Resources} class loader
*
* @return the context class loader
*/
public static ClassLoader getContextClassLoader() {
return getContextClassLoader(Resources.class);
}
/**
* Returns current thread context class loader or context class's class loader
*
* @param contextClass context class to use
* @return the context class loader
*/
public static ClassLoader getContextClassLoader(Class contextClass) {
return Objects.firstNonNull(
Thread.currentThread().getContextClassLoader(),
contextClass.getClassLoader()
);
}
}