com.github.datalking.io.ClassPathResource Maven / Gradle / Ivy

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package com.github.datalking.io;

import com.github.datalking.util.Assert;
import com.github.datalking.util.ClassUtils;
import com.github.datalking.util.ObjectUtils;
import com.github.datalking.util.StringUtils;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

public class ClassPathResource implements Resource {

    private final String path;

    private ClassLoader classLoader;

    private Class clazz;

    public ClassPathResource(String path) {
        this(path, (ClassLoader) null);
    }

    public ClassPathResource(String path, ClassLoader classLoader) {
        Assert.notNull(path, "Path must not be null");
        String pathToUse = StringUtils.cleanPath(path);
        if (pathToUse.startsWith("/")) {
            pathToUse = pathToUse.substring(1);
        }
        this.path = pathToUse;
        this.classLoader = (classLoader != null ? classLoader : ClassUtils.getDefaultClassLoader());
    }

    public ClassPathResource(String path, Class clazz) {
        Assert.notNull(path, "Path must not be null");
        this.path = StringUtils.cleanPath(path);
        this.clazz = clazz;
    }

    protected ClassPathResource(String path, ClassLoader classLoader, Class clazz) {
        this.path = StringUtils.cleanPath(path);
        this.classLoader = classLoader;
        this.clazz = clazz;
    }

    public final String getPath() {
        return this.path;
    }

    public final ClassLoader getClassLoader() {
        return (this.clazz != null ? this.clazz.getClassLoader() : this.classLoader);
    }

    @Override
    public boolean exists() {
        return (resolveURL() != null);
    }

    protected URL resolveURL() {
        if (this.clazz != null) {
            return this.clazz.getResource(this.path);
        } else if (this.classLoader != null) {
            return this.classLoader.getResource(this.path);
        } else {
            return ClassLoader.getSystemResource(this.path);
        }
    }

    @Override
    public InputStream getInputStream() throws IOException {
        InputStream is;
        if (this.clazz != null) {
            is = this.clazz.getResourceAsStream(this.path);
        } else if (this.classLoader != null) {
            is = this.classLoader.getResourceAsStream(this.path);
        } else {
            is = ClassLoader.getSystemResourceAsStream(this.path);
        }
        if (is == null) {
            throw new FileNotFoundException(getDescription() + " cannot be opened because it does not exist");
        }
        return is;
    }

    public URL getURL() throws IOException {
        URL url = resolveURL();
        if (url == null) {
            throw new FileNotFoundException(getDescription() + " cannot be resolved to URL because it does not exist");
        }
        return url;
    }

    public ClassPathResource createRelative(String relativePath) {
        String pathToUse = StringUtils.applyRelativePath(this.path, relativePath);
        return new ClassPathResource(pathToUse, this.classLoader, this.clazz);
    }


    public String getFilename() {
        return StringUtils.getFilename(this.path);
    }

    public String getDescription() {
        StringBuilder builder = new StringBuilder("class path resource [");
        String pathToUse = path;
        if (this.clazz != null && !pathToUse.startsWith("/")) {
            builder.append(ClassUtils.classPackageAsResourcePath(this.clazz));
            builder.append('/');
        }
        if (pathToUse.startsWith("/")) {
            pathToUse = pathToUse.substring(1);
        }
        builder.append(pathToUse);
        builder.append(']');
        return builder.toString();
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (obj instanceof ClassPathResource) {
            ClassPathResource otherRes = (ClassPathResource) obj;
            return (this.path.equals(otherRes.path) &&
                    ObjectUtils.nullSafeEquals(this.classLoader, otherRes.classLoader) &&
                    ObjectUtils.nullSafeEquals(this.clazz, otherRes.clazz));
        }
        return false;
    }

    @Override
    public int hashCode() {
        return this.path.hashCode();
    }

}