/*
 * Copyright 2002-2018 the original author or authors.
 *
 * 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 org.springframework.core.io.support;

import java.io.IOException;
import java.util.Map;
import java.util.Properties;

import org.springframework.core.env.PropertiesPropertySource;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.Resource;
import org.springframework.lang.Nullable;
import org.springframework.util.StringUtils;

Subclass of PropertiesPropertySource that loads a Properties object from a given Resource or resource location such as "classpath:/com/myco/foo.properties" or "file:/path/to/file.xml". 
Both traditional and XML-based properties file formats are supported; however, in order for XML processing to take effect, the underlying Resource's getFilename() method must return a non-null value that ends in ".xml". 
Author:
Chris Beams, Juergen Hoeller
See Also:
Resource
EncodedResource
Since:
3.1/**
 * Subclass of {@link PropertiesPropertySource} that loads a {@link Properties} object
 * from a given {@link org.springframework.core.io.Resource} or resource location such as
 * {@code "classpath:/com/myco/foo.properties"} or {@code "file:/path/to/file.xml"}.
 *
 * <p>Both traditional and XML-based properties file formats are supported; however, in
 * order for XML processing to take effect, the underlying {@code Resource}'s
 * {@link org.springframework.core.io.Resource#getFilename() getFilename()} method must
 * return a non-{@code null} value that ends in {@code ".xml"}.
 *
 * @author Chris Beams
 * @author Juergen Hoeller
 * @since 3.1
 * @see org.springframework.core.io.Resource
 * @see org.springframework.core.io.support.EncodedResource
 */
public class ResourcePropertySource extends PropertiesPropertySource {

	
The original resource name, if different from the given name. /** The original resource name, if different from the given name. */
	@Nullable
	private final String resourceName;


	
Create a PropertySource having the given name based on Properties
loaded from the given encoded resource.
/**
	 * Create a PropertySource having the given name based on Properties
	 * loaded from the given encoded resource.
	 */
	public ResourcePropertySource(String name, EncodedResource resource) throws IOException {
		super(name, PropertiesLoaderUtils.loadProperties(resource));
		this.resourceName = getNameForResource(resource.getResource());
	}

	
Create a PropertySource based on Properties loaded from the given resource. The name of the PropertySource will be generated based on the description of the given resource. /**
	 * Create a PropertySource based on Properties loaded from the given resource.
	 * The name of the PropertySource will be generated based on the
	 * {@link Resource#getDescription() description} of the given resource.
	 */
	public ResourcePropertySource(EncodedResource resource) throws IOException {
		super(getNameForResource(resource.getResource()), PropertiesLoaderUtils.loadProperties(resource));
		this.resourceName = null;
	}

	
Create a PropertySource having the given name based on Properties
loaded from the given encoded resource.
/**
	 * Create a PropertySource having the given name based on Properties
	 * loaded from the given encoded resource.
	 */
	public ResourcePropertySource(String name, Resource resource) throws IOException {
		super(name, PropertiesLoaderUtils.loadProperties(new EncodedResource(resource)));
		this.resourceName = getNameForResource(resource);
	}

	
Create a PropertySource based on Properties loaded from the given resource. The name of the PropertySource will be generated based on the description of the given resource. /**
	 * Create a PropertySource based on Properties loaded from the given resource.
	 * The name of the PropertySource will be generated based on the
	 * {@link Resource#getDescription() description} of the given resource.
	 */
	public ResourcePropertySource(Resource resource) throws IOException {
		super(getNameForResource(resource), PropertiesLoaderUtils.loadProperties(new EncodedResource(resource)));
		this.resourceName = null;
	}

	
Create a PropertySource having the given name based on Properties loaded from the given resource location and using the given class loader to load the resource (assuming it is prefixed with classpath:). /**
	 * Create a PropertySource having the given name based on Properties loaded from
	 * the given resource location and using the given class loader to load the
	 * resource (assuming it is prefixed with {@code classpath:}).
	 */
	public ResourcePropertySource(String name, String location, ClassLoader classLoader) throws IOException {
		this(name, new DefaultResourceLoader(classLoader).getResource(location));
	}

	
Create a PropertySource based on Properties loaded from the given resource location and use the given class loader to load the resource, assuming it is prefixed with classpath:. The name of the PropertySource will be generated based on the description of the resource. /**
	 * Create a PropertySource based on Properties loaded from the given resource
	 * location and use the given class loader to load the resource, assuming it is
	 * prefixed with {@code classpath:}. The name of the PropertySource will be
	 * generated based on the {@link Resource#getDescription() description} of the
	 * resource.
	 */
	public ResourcePropertySource(String location, ClassLoader classLoader) throws IOException {
		this(new DefaultResourceLoader(classLoader).getResource(location));
	}

	
Create a PropertySource having the given name based on Properties loaded from the given resource location. The default thread context class loader will be used to load the resource (assuming the location string is prefixed with classpath:. /**
	 * Create a PropertySource having the given name based on Properties loaded from
	 * the given resource location. The default thread context class loader will be
	 * used to load the resource (assuming the location string is prefixed with
	 * {@code classpath:}.
	 */
	public ResourcePropertySource(String name, String location) throws IOException {
		this(name, new DefaultResourceLoader().getResource(location));
	}

	
Create a PropertySource based on Properties loaded from the given resource location. The name of the PropertySource will be generated based on the description of the resource. /**
	 * Create a PropertySource based on Properties loaded from the given resource
	 * location. The name of the PropertySource will be generated based on the
	 * {@link Resource#getDescription() description} of the resource.
	 */
	public ResourcePropertySource(String location) throws IOException {
		this(new DefaultResourceLoader().getResource(location));
	}

	private ResourcePropertySource(String name, @Nullable String resourceName, Map<String, Object> source) {
		super(name, source);
		this.resourceName = resourceName;
	}


	
Return a potentially adapted variant of this ResourcePropertySource, overriding the previously given (or derived) name with the specified name. 
Since:
4.0.4/**
	 * Return a potentially adapted variant of this {@link ResourcePropertySource},
	 * overriding the previously given (or derived) name with the specified name.
	 * @since 4.0.4
	 */
	public ResourcePropertySource withName(String name) {
		if (this.name.equals(name)) {
			return this;
		}
		// Store the original resource name if necessary...
		if (this.resourceName != null) {
			if (this.resourceName.equals(name)) {
				return new ResourcePropertySource(this.resourceName, null, this.source);
			}
			else {
				return new ResourcePropertySource(name, this.resourceName, this.source);
			}
		}
		else {
			// Current name is resource name -> preserve it in the extra field...
			return new ResourcePropertySource(name, this.name, this.source);
		}
	}

	
Return a potentially adapted variant of this ResourcePropertySource, overriding the previously given name (if any) with the original resource name (equivalent to the name generated by the name-less constructor variants). 
Since:
4.1/**
	 * Return a potentially adapted variant of this {@link ResourcePropertySource},
	 * overriding the previously given name (if any) with the original resource name
	 * (equivalent to the name generated by the name-less constructor variants).
	 * @since 4.1
	 */
	public ResourcePropertySource withResourceName() {
		if (this.resourceName == null) {
			return this;
		}
		return new ResourcePropertySource(this.resourceName, null, this.source);
	}


	
Return the description for the given Resource; if the description is
empty, return the class name of the resource plus its identity hash code.
See Also:
getDescription.getDescription()/**
	 * Return the description for the given Resource; if the description is
	 * empty, return the class name of the resource plus its identity hash code.
	 * @see org.springframework.core.io.Resource#getDescription()
	 */
	private static String getNameForResource(Resource resource) {
		String name = resource.getDescription();
		if (!StringUtils.hasText(name)) {
			name = resource.getClass().getSimpleName() + "@" + System.identityHashCode(resource);
		}
		return name;
	}

}