org.apache.felix.framework.cache.Content Maven / Gradle / Ivy
/*
* 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.felix.framework.cache;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Enumeration;
public interface Content
{
/**
*
* This method must be called when the content is no longer needed so
* that any resourses being used (e.g., open files) can be closed. Once
* this method is called, the content is no longer usable. If the content
* is already closed, then calls on this method should have no effect.
*
**/
void close();
/**
*
* This method determines if the specified named entry is contained in
* the associated content. The entry name is a relative path with '/'
* separators.
*
* @param name The name of the entry to find.
* @return true if a corresponding entry was found, false
* otherwise.
**/
boolean hasEntry(String name);
/**
*
* Returns an enumeration of entry names as String objects.
* An entry name is a path constructed with '/' as path element
* separators and is relative to the root of the content. Entry names
* for entries that represent directories should end with the '/'
* character.
*
* @returns An enumeration of entry names or null.
**/
Enumeration getEntries();
/**
*
* This method returns the named entry as an array of bytes.
*
* @param name The name of the entry to retrieve as a byte array.
* @return An array of bytes if the corresponding entry was found, null
* otherwise.
**/
byte[] getEntryAsBytes(String name);
/**
*
* This method returns the named entry as an input stream.
*
* @param name The name of the entry to retrieve as an input stream.
* @return An input stream if the corresponding entry was found, null
* otherwise.
* @throws java.io.IOException if any error occurs.
**/
InputStream getEntryAsStream(String name) throws IOException;
/**
*
* This method returns the named entry as an IContent Typically,
* this method only makes sense for entries that correspond to some form
* of aggregated resource (e.g., an embedded JAR file or directory), but
* implementations are free to interpret this however makes sense. This method
* should return a new IContent instance for every invocation and
* the caller is responsible for opening and closing the returned content
* object.
*
* @param name The name of the entry to retrieve as an IContent.
* @return An IContent instance if a corresponding entry was found,
* null otherwise.
**/
Content getEntryAsContent(String name);
/**
*
* This method returns the named entry as a file in the file system for
* use as a native library. It may not be possible for all content
* implementations (e.g., memory only) to implement this method, in which
* case it is acceptable to return null. Since native libraries
* can only be associated with a single class loader, this method should
* return a unique file per request.
*
* @param name The name of the entry to retrieve as a file.
* @return A string corresponding to the absolute path of the file if a
* corresponding entry was found, null otherwise.
**/
String getEntryAsNativeLibrary(String name);
/**
*
* This method allows retrieving an entry as a local URL.
*
*
* @param name The name of the entry to retrieve as a URL
* @return A URL using a local protocol such as file, jar
* or null if not possible.
*/
URL getEntryAsURL(String name);
}