juneau-core/juneau-marshall/src/main/java/org/apache/juneau/utils/ClasspathResourceManager.java - juneau - Git at Google

 // ***************************************************************************************************************************
 // * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
 // * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
 // * to you 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.apache.juneau.utils;

 import java.io.*;
 import java.util.*;
 import java.util.concurrent.*;

 import org.apache.juneau.internal.*;

 /**
  * Class for retrieving and caching resource files from the classpath.
  */
 public final class ClasspathResourceManager {

 	// Maps resource names+locales to found resources.
 	private final ConcurrentHashMap<ResourceKey,byte[]> byteCache;
 	private final ConcurrentHashMap<ResourceKey,String> stringCache;

 	private final Class<?> baseClass;
 	private final ClasspathResourceFinder resourceFinder;
 	private final boolean useCache;

 	/**
 	 * Constructor.
 	 *
 	 * @param baseClass The default class to use for retrieving resources from the classpath.
 	 * @param resourceFinder The resource finder implementation.
 	 * @param useCache If <jk>true</jk>, retrieved resources are stored in an in-memory cache for fast lookup.
 	 */
 	public ClasspathResourceManager(Class<?> baseClass, ClasspathResourceFinder resourceFinder, boolean useCache) {
 		this.baseClass = baseClass;
 		this.resourceFinder = resourceFinder;
 		this.useCache = useCache;
 		if (useCache) {
 			this.byteCache = new ConcurrentHashMap<>();
 			this.stringCache = new ConcurrentHashMap<>();
 		} else {
 			this.byteCache = null;
 			this.stringCache = null;
 		}
 	}

 	/**
 	 * Constructor.
 	 *
 	 * <p>
 	 * Uses default {@link ClasspathResourceFinderBasic} for finding resources.
 	 *
 	 * @param baseClass The default class to use for retrieving resources from the classpath.
 	 */
 	public ClasspathResourceManager(Class<?> baseClass) {
 		this(baseClass, new ClasspathResourceFinderBasic(), false);
 	}

 	/**
 	 * Finds the resource with the given name.
 	 *
 	 * @param name Name of the desired resource.
 	 * @return An input stream to the object, or <jk>null</jk> if the resource could not be found.
 	 * @throws IOException Thrown by underlying stream.
 	 */
 	public InputStream getStream(String name) throws IOException {
 		return getStream(name, null);
 	}

 	/**
 	 * Finds the resource with the given name for the specified locale and returns it as an input stream.
 	 *
 	 * @param name Name of the desired resource.
 	 * @param locale The locale.  Can be <jk>null</jk>.
 	 * @return An input stream to the object, or <jk>null</jk> if the resource could not be found.
 	 * @throws IOException Thrown by underlying stream.
 	 */
 	public InputStream getStream(String name, Locale locale) throws IOException {
 		return getStream(baseClass, name, locale);
 	}

 	/**
 	 * Finds the resource with the given name for the specified locale and returns it as an input stream.
 	 *
 	 * @param baseClass
 	 * 	Overrides the default class to use for retrieving the classpath resource.
 	 * 	<br>If <jk>null</jk>, uses the base class passed in through the constructor of this class.
 	 * @param name Name of the desired resource.
 	 * @param locale The locale.  Can be <jk>null</jk>.
 	 * @return An input stream to the object, or <jk>null</jk> if the resource could not be found.
 	 * @throws IOException Thrown by underlying stream.
 	 */
 	public InputStream getStream(Class<?> baseClass, String name, Locale locale) throws IOException {

 		if (baseClass == null)
 			baseClass = this.baseClass;

 		if (! useCache)
 			return resourceFinder.findResource(baseClass, name, locale);

 		ResourceKey key = new ResourceKey(name, locale);

 		byte[] r = byteCache.get(key);
 		if (r == null) {
 			try (InputStream is = resourceFinder.findResource(baseClass, name, locale)) {
 				if (is != null)
 					byteCache.putIfAbsent(key, IOUtils.readBytes(is, 1024));
 			}
 		}

 		r = byteCache.get(key);
 		return r == null ? null : new ByteArrayInputStream(r);
 	}

 	/**
 	 * Finds the resource with the given name and converts it to a simple string.
 	 *
 	 * @param name Name of the desired resource.
 	 * @return The resource converted to a string, or <jk>null</jk> if the resource could not be found.
 	 * @throws IOException Thrown by underlying stream.
 	 */
 	public String getString(String name) throws IOException {
 		return getString(baseClass, name, null);
 	}

 	/**
 	 * Finds the resource with the given name and converts it to a simple string.
 	 *
 	 * @param baseClass
 	 * 	Overrides the default class to use for retrieving the classpath resource.
 	 * 	<br>If <jk>null</jk>, uses the base class passed in through the constructor of this class.
 	 * @param name Name of the desired resource.
 	 * @return The resource converted to a string, or <jk>null</jk> if the resource could not be found.
 	 * @throws IOException Thrown by underlying stream.
 	 */
 	public String getString(Class<?> baseClass, String name) throws IOException {
 		return getString(baseClass, name, null);
 	}

 	/**
 	 * Finds the resource with the given name and converts it to a simple string.
 	 *
 	 * @param name Name of the desired resource.
 	 * @param locale The locale.  Can be <jk>null</jk>.
 	 * @return The resource converted to a string, or <jk>null</jk> if the resource could not be found.
 	 * @throws IOException Thrown by underlying stream.
 	 */
 	public String getString(String name, Locale locale) throws IOException {
 		return getString(baseClass, name, locale);
 	}

 	/**
 	 * Finds the resource with the given name and converts it to a simple string.
 	 *
 	 * @param baseClass
 	 * 	Overrides the default class to use for retrieving the classpath resource.
 	 * 	<br>If <jk>null</jk>, uses the base class passed in through the constructor of this class.
 	 * @param name Name of the desired resource.
 	 * @param locale The locale.  Can be <jk>null</jk>.
 	 * @return The resource converted to a string, or <jk>null</jk> if the resource could not be found.
 	 * @throws IOException Thrown by underlying stream.
 	 */
 	public String getString(Class<?> baseClass, String name, Locale locale) throws IOException {

 		if (baseClass == null)
 			baseClass = this.baseClass;

 		if (! useCache) {
 			try (InputStream is = resourceFinder.findResource(baseClass, name, locale)) {
 				return IOUtils.read(is, IOUtils.UTF8);
 			}
 		}

 		ResourceKey key = new ResourceKey(name, locale);

 		String r = stringCache.get(key);
 		if (r == null) {
 			try (InputStream is = resourceFinder.findResource(baseClass, name, locale)) {
 				if (is != null)
 					stringCache.putIfAbsent(key, IOUtils.read(is, IOUtils.UTF8));
 			}
 		}

 		return stringCache.get(key);
 	}

 	private class ResourceKey {
 		final String name;
 		final Locale locale;

 		ResourceKey(String name, Locale locale) {
 			this.name = name;
 			this.locale = locale;
 		}

 		@Override
 		public int hashCode() {
 			return name.hashCode() + (locale == null ? 0 : locale.hashCode());
 		}

 		@Override
 		public boolean equals(Object o) {
 			if (o == null)
 				return false;
 			ResourceKey ok = (ResourceKey)o;
 			return ObjectUtils.equals(name, ok.name) && ObjectUtils.equals(locale, ok.locale);
 		}
 	}
 }
	// ***************************************************************************************************************************
	// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file *
	// * distributed with this work for additional information regarding copyright ownership. The ASF licenses this file *
	// * to you 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.apache.juneau.utils;

	import java.io.*;
	import java.util.*;
	import java.util.concurrent.*;

	import org.apache.juneau.internal.*;

	/**
	* Class for retrieving and caching resource files from the classpath.
	*/
	public final class ClasspathResourceManager {

	// Maps resource names+locales to found resources.
	private final ConcurrentHashMap<ResourceKey,byte[]> byteCache;
	private final ConcurrentHashMap<ResourceKey,String> stringCache;

	private final Class<?> baseClass;
	private final ClasspathResourceFinder resourceFinder;
	private final boolean useCache;

	/**
	* Constructor.
	*
	* @param baseClass The default class to use for retrieving resources from the classpath.
	* @param resourceFinder The resource finder implementation.
	* @param useCache If <jk>true</jk>, retrieved resources are stored in an in-memory cache for fast lookup.
	*/
	public ClasspathResourceManager(Class<?> baseClass, ClasspathResourceFinder resourceFinder, boolean useCache) {
	this.baseClass = baseClass;
	this.resourceFinder = resourceFinder;
	this.useCache = useCache;
	if (useCache) {
	this.byteCache = new ConcurrentHashMap<>();
	this.stringCache = new ConcurrentHashMap<>();
	} else {
	this.byteCache = null;
	this.stringCache = null;
	}
	}

	/**
	* Constructor.
	*
	* <p>
	* Uses default {@link ClasspathResourceFinderBasic} for finding resources.
	*
	* @param baseClass The default class to use for retrieving resources from the classpath.
	*/
	public ClasspathResourceManager(Class<?> baseClass) {
	this(baseClass, new ClasspathResourceFinderBasic(), false);
	}

	/**
	* Finds the resource with the given name.
	*
	* @param name Name of the desired resource.
	* @return An input stream to the object, or <jk>null</jk> if the resource could not be found.
	* @throws IOException Thrown by underlying stream.
	*/
	public InputStream getStream(String name) throws IOException {
	return getStream(name, null);
	}

	/**
	* Finds the resource with the given name for the specified locale and returns it as an input stream.
	*
	* @param name Name of the desired resource.
	* @param locale The locale. Can be <jk>null</jk>.
	* @return An input stream to the object, or <jk>null</jk> if the resource could not be found.
	* @throws IOException Thrown by underlying stream.
	*/
	public InputStream getStream(String name, Locale locale) throws IOException {
	return getStream(baseClass, name, locale);
	}

	/**
	* Finds the resource with the given name for the specified locale and returns it as an input stream.
	*
	* @param baseClass
	* Overrides the default class to use for retrieving the classpath resource.
	* <br>If <jk>null</jk>, uses the base class passed in through the constructor of this class.
	* @param name Name of the desired resource.
	* @param locale The locale. Can be <jk>null</jk>.
	* @return An input stream to the object, or <jk>null</jk> if the resource could not be found.
	* @throws IOException Thrown by underlying stream.
	*/
	public InputStream getStream(Class<?> baseClass, String name, Locale locale) throws IOException {

	if (baseClass == null)
	baseClass = this.baseClass;

	if (! useCache)
	return resourceFinder.findResource(baseClass, name, locale);

	ResourceKey key = new ResourceKey(name, locale);

	byte[] r = byteCache.get(key);
	if (r == null) {
	try (InputStream is = resourceFinder.findResource(baseClass, name, locale)) {
	if (is != null)
	byteCache.putIfAbsent(key, IOUtils.readBytes(is, 1024));
	}
	}

	r = byteCache.get(key);
	return r == null ? null : new ByteArrayInputStream(r);
	}

	/**
	* Finds the resource with the given name and converts it to a simple string.
	*
	* @param name Name of the desired resource.
	* @return The resource converted to a string, or <jk>null</jk> if the resource could not be found.
	* @throws IOException Thrown by underlying stream.
	*/
	public String getString(String name) throws IOException {
	return getString(baseClass, name, null);
	}

	/**
	* Finds the resource with the given name and converts it to a simple string.
	*
	* @param baseClass
	* Overrides the default class to use for retrieving the classpath resource.
	* <br>If <jk>null</jk>, uses the base class passed in through the constructor of this class.
	* @param name Name of the desired resource.
	* @return The resource converted to a string, or <jk>null</jk> if the resource could not be found.
	* @throws IOException Thrown by underlying stream.
	*/
	public String getString(Class<?> baseClass, String name) throws IOException {
	return getString(baseClass, name, null);
	}

	/**
	* Finds the resource with the given name and converts it to a simple string.
	*
	* @param name Name of the desired resource.
	* @param locale The locale. Can be <jk>null</jk>.
	* @return The resource converted to a string, or <jk>null</jk> if the resource could not be found.
	* @throws IOException Thrown by underlying stream.
	*/
	public String getString(String name, Locale locale) throws IOException {
	return getString(baseClass, name, locale);
	}

	/**
	* Finds the resource with the given name and converts it to a simple string.
	*
	* @param baseClass
	* Overrides the default class to use for retrieving the classpath resource.
	* <br>If <jk>null</jk>, uses the base class passed in through the constructor of this class.
	* @param name Name of the desired resource.
	* @param locale The locale. Can be <jk>null</jk>.
	* @return The resource converted to a string, or <jk>null</jk> if the resource could not be found.
	* @throws IOException Thrown by underlying stream.
	*/
	public String getString(Class<?> baseClass, String name, Locale locale) throws IOException {

	if (baseClass == null)
	baseClass = this.baseClass;

	if (! useCache) {
	try (InputStream is = resourceFinder.findResource(baseClass, name, locale)) {
	return IOUtils.read(is, IOUtils.UTF8);
	}
	}

	ResourceKey key = new ResourceKey(name, locale);

	String r = stringCache.get(key);
	if (r == null) {
	try (InputStream is = resourceFinder.findResource(baseClass, name, locale)) {
	if (is != null)
	stringCache.putIfAbsent(key, IOUtils.read(is, IOUtils.UTF8));
	}
	}

	return stringCache.get(key);
	}

	private class ResourceKey {
	final String name;
	final Locale locale;

	ResourceKey(String name, Locale locale) {
	this.name = name;
	this.locale = locale;
	}

	@Override
	public int hashCode() {
	return name.hashCode() + (locale == null ? 0 : locale.hashCode());
	}

	@Override
	public boolean equals(Object o) {
	if (o == null)
	return false;
	ResourceKey ok = (ResourceKey)o;
	return ObjectUtils.equals(name, ok.name) && ObjectUtils.equals(locale, ok.locale);
	}
	}
	}