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/*
* Copyright 2006-2023 Prowide
*
* 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 com.prowidesoftware.swift.utils;
import java.io.*;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import org.apache.commons.lang3.StringUtils;
/**
* Miscellaneous helper functions.
*/
public class Lib {
private Lib() {}
/**
* Read the content of the given file into a string.
*
* @param filename the name of the file to be read
* @throws IOException if an error occurs during read
* @see #readFile(File)
* @since 7.6
*/
public static String readFile(final String filename) throws IOException {
return readFile(new File(filename));
}
/**
* Read the content of the given file into a string, using UTF8 as default encoding
*
* @param file the file to read
* @return file contents
* @throws IOException if an error occurs during read
* @see #readFile(File, String)
*/
public static String readFile(final File file) throws IOException {
return readFile(file, null);
}
/**
* Read the content of the given file into a string.
*
* @param file the file to be read
* @param encoding encoding to use, may be null in which case UTF-8 is used as default
* @return the file contents or null if file is null or does not exist, or can't be read, or is not a file
* @throws IOException if an error occurs during read
*/
public static String readFile(final File file, final String encoding) throws IOException {
if (file == null || !file.exists() || !file.canRead() || !file.isFile()) {
return null;
}
final String charset = encoding != null ? encoding : "UTF-8";
final StringBuilder sb = new StringBuilder((int) file.length());
try (FileInputStream fileStream = new FileInputStream(file);
BufferedReader in = new BufferedReader(new InputStreamReader(fileStream, charset))) {
int c;
while ((c = in.read()) != -1) {
sb.append((char) c);
}
}
return sb.toString();
}
/**
* Read a resource from classpath using the context classloader, using UTF8 as default encoding
*
* @param resource the resource name to read, must not be null
* @see #readResource(String, String)
* @since 7.10.0
*/
public static String readResource(final String resource) throws IOException {
return readResource(resource, null);
}
/**
* Read a resource from classpath using the current thread classloader
*
* @param resource the resource name to read, must not be null
* @param encoding optional, may be null in which case UTF-8 is used as default
* @return read content or empty string if resource cannot be loaded
* @throws IOException if the resource stream cannot be read
* @see #readResource(String, String, Class)
* @since 7.7
*/
public static String readResource(final String resource, final String encoding) throws IOException {
return readResource(resource, encoding, null);
}
/**
* Read a resource from classpath.
*
* The implementation will attempt first to use the current thread classloader, and if the resource is not found
* it will use the classloader from the parameter class. This class parameter should be the class that is calling
* this method.
*
* @param resource the resource name to read, must not be null
* @param encoding optional, may be null in which case UTF-8 is used as default
* @param clazz optional parameter with the loading object class, for the fallback attempt
* @return read content or empty string if resource cannot be loaded
* @throws IOException if the resource stream cannot be read
* @since 8.0.3
*/
public static String readResource(final String resource, final String encoding, Class clazz) throws IOException {
InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(resource);
if (is == null && clazz != null) {
// if not found we fallback with this loading object classloader
is = clazz.getClassLoader().getResourceAsStream(resource);
}
if (is == null) {
return StringUtils.EMPTY;
}
return readStream(is, encoding);
}
/**
* Read the content of the given stream into a string.
*
* @param stream the contents to read
* @return the read content
* @throws IOException if the resource stream cannot be read
* @see #readStream(InputStream, String)
* @since 7.7
*/
public static String readStream(final InputStream stream) throws IOException {
return readStream(stream, (Charset) null);
}
/**
* Read the content of the given stream into a string.
*
* @param stream the contents to read
* @param enconding encoding to use, , may be null in which case UTF-8 is used as default
* @return the read content
* @throws IOException if the resource stream cannot be read
* @since 7.7
*/
public static String readStream(final InputStream stream, final String enconding) throws IOException {
if (stream == null) {
return null;
}
final StringBuilder out = new StringBuilder();
final String enc = enconding != null ? enconding : "UTF-8";
try (Reader in = new InputStreamReader(stream, enc)) {
int c;
while ((c = in.read()) != -1) {
out.append((char) c);
}
}
return out.toString();
}
/**
* Reads the content of the given input stream into a string using the specified encoding.
*
* @param stream the contents to read
* @param charset the encoding to use, defaults to UTF-8 if null
* @return the read content
* @throws IOException if the resource stream cannot be read
* @since 9.2.12
*/
public static String readStream(final InputStream stream, final Charset charset) throws IOException {
if (stream == null) {
return null;
}
final StringBuilder out = new StringBuilder();
try (Reader in = new InputStreamReader(stream, charset != null ? charset : StandardCharsets.UTF_8)) {
int c;
while ((c = in.read()) != -1) {
out.append((char) c);
}
}
return out.toString();
}
/**
* Read the content of the given reader into a string.
*
* @param reader the contents to read
* @return the read content
* @throws IOException if the resource stream cannot be read
* @since 7.7
*/
public static String readReader(final Reader reader) throws IOException {
if (reader == null) {
return null;
}
final StringBuilder out = new StringBuilder();
try {
int c;
while ((c = reader.read()) != -1) {
out.append((char) c);
}
} finally {
reader.close();
}
return out.toString();
}
}