br.com.esec.icpm.util.StreamUtils Maven / Gradle / Ivy

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package br.com.esec.icpm.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

import org.apache.commons.lang.StringUtils;

public class StreamUtils {

	public static InputStream load(String path) {
		InputStream stream = null;
		
		if (StringUtils.isEmpty(path))
			return null;
		
		if (stream == null || isEmpty(stream))
			stream = tryGetOnClass(path);
		if (stream == null || isEmpty(stream))
			stream = tryGetOnClass("/" + path);

		if (stream == null || isEmpty(stream))
			stream = tryGetOnClassLoader(path);
		if (stream == null || isEmpty(stream))
			stream = tryGetOnClassLoader("/" + path);

		if (stream == null || isEmpty(stream))
			stream = tryGetByFilePath(path);
		if (stream == null || isEmpty(stream))
			stream = tryGetByFilePath("/" + path);

		if (stream == null || isEmpty(stream))
			stream = tryMountUrl(path);
		if (stream == null || isEmpty(stream))
			stream = tryMountUrl("/" + path);

		if (stream == null || isEmpty(stream))
			throw new IllegalStateException("The system can not found the path '" + path + "'.");

		return stream;
	}

	private static boolean isEmpty(InputStream stream) {
		try {
			return stream.available() <= 0;
		} catch (IOException e) {
			return false;
		}
	}

	private static InputStream tryGetOnClass(String path) {
		try {
			return UrlUtils.class.getResourceAsStream(path);
		} catch (Exception e) {
			return null;
		}
	}

	private static InputStream tryGetOnClassLoader(String path) {
		try {
			ClassLoader loader = Thread.currentThread().getContextClassLoader();
			return loader.getResourceAsStream(path);
		} catch (Exception e) {
			return null;
		}
	}

	private static InputStream tryGetByFilePath(String path) {
		try {
			File file = new File(path);
			if (!file.exists()) {
				return null;
			}
			return new FileInputStream(file);
		} catch (Exception e) {
			return null;
		}
	}

	private static InputStream tryMountUrl(String path) {
		try {
			InputStream stream = new URL(path).openStream();
			if (stream.available() > 0)
				return stream;
			return null;
		} catch (IOException e) {
			return null;
		}
	}

}