HomeDirectoryLocationStrategy.java
/*
* 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
*
* https://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.commons.configuration2.io;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.SystemProperties;
/**
* A specialized implementation of {@code FileLocationStrategy} which searches for files in the user's home directory or
* another special configurable directory.
* <p>
* This strategy implementation ignores the URL stored in the passed in {@link FileLocator}. It constructs a file path
* from the configured home directory (which is the user's home directory per default, but can be changed to another
* path), optionally the base path, and the file name. If the resulting path points to an existing file, its URL is
* returned.
* </p>
* <p>
* When constructing an instance it can be configured whether the base path should be taken into account. If this option
* is set, the base path is appended to the home directory if it is not {@code null}. This is useful for instance to
* select a specific sub directory of the user's home directory. If this option is set to <strong>false</strong>, the base path is
* always ignored, and only the file name is evaluated.
* </p>
* <p>
* See {@link AbstractFileLocationStrategy} learn how to grant an deny URL schemes and hosts.
* </p>
*
* @see AbstractFileLocationStrategy
*/
public class HomeDirectoryLocationStrategy extends AbstractFileLocationStrategy {
/**
* Builds new instances of {@link HomeDirectoryLocationStrategy}.
*
* @since 2.15.0
*/
public static class Builder extends AbstractBuilder<HomeDirectoryLocationStrategy, Builder> {
/** The flag whether the base path is to be taken into account. */
private boolean evaluateBasePath;
/** The home directory to be searched for the requested file. */
private String homeDirectory;
/**
* Constructs a new instance.
*/
public Builder() {
// empty
}
@Override
public HomeDirectoryLocationStrategy get() throws IOException {
return new HomeDirectoryLocationStrategy(this);
}
/**
* Sets whether the base path should be evaluated.
*
* @param evaluateBasePath whether the base path should be evaluated.
* @return {@code this} instance..
*/
public Builder setEvaluateBasePath(final boolean evaluateBasePath) {
this.evaluateBasePath = evaluateBasePath;
return asThis();
}
/**
* Sets the path to the home directory (may be {@code null}).
*
* @param homeDirectory The path to the home directory (may be {@code null})
* @return {@code this} instance..
*/
public Builder setHomeDirectory(final String homeDirectory) {
this.homeDirectory = homeDirectory;
return asThis();
}
}
/**
* Gets the home directory to be used by a new instance. If a directory name is provided, it is used. Otherwise, the
* user's home directory is looked up.
*
* @param homeDir The passed in home directory
* @return The directory to be used
*/
private static String getHomeDirectory(final String homeDir) {
return homeDir != null ? homeDir : SystemProperties.getUserHome();
}
/** The flag whether the base path is to be taken into account. */
private final boolean evaluateBasePath;
/** The home directory to be searched for the requested file. */
private final String homeDirectory;
/**
* Creates a new instance of {@code HomeDirectoryLocationStrategy} with default settings. The home directory is set to
* the user's home directory. The base path flag is set to <strong>false</strong> (which means that the base path is ignored).
*/
public HomeDirectoryLocationStrategy() {
this(false);
}
/**
* Creates a new instance of {@code HomeDirectoryLocationStrategy} and initializes the base path flag. The home
* directory is set to the user's home directory.
*
* @param withBasePath A flag whether the base path should be evaluated.
* @deprecated Use {@link Builder#setEvaluateBasePath(boolean)}.
*/
@Deprecated
public HomeDirectoryLocationStrategy(final boolean withBasePath) {
this(new Builder().setHomeDirectory(null).setEvaluateBasePath(withBasePath));
}
/**
* Constructs a new instance.
*
* @param builder How to build the instance.
*/
private HomeDirectoryLocationStrategy(final Builder builder) {
super(builder);
homeDirectory = getHomeDirectory(builder.homeDirectory);
evaluateBasePath = builder.evaluateBasePath;
}
/**
* Creates a new instance of {@code HomeDirectoryLocationStrategy} and initializes it with the specified settings.
*
* @param homeDir The path to the home directory (may be {@code null}).
* @param withBasePath A flag whether the base path should be evaluated.
* @deprecated Use {@link Builder#setHomeDirectory(String)}.
*/
@Deprecated
public HomeDirectoryLocationStrategy(final String homeDir, final boolean withBasePath) {
this(new Builder().setHomeDirectory(homeDir).setEvaluateBasePath(withBasePath));
}
/**
* Determines the base path to be used for the current locate() operation.
*
* @param locator The {@code FileLocator}
* @return The base path to be used
*/
private String getBasePath(final FileLocator locator) {
if (isEvaluateBasePath() && StringUtils.isNotEmpty(locator.getBasePath())) {
return FileLocatorUtils.appendPath(getHomeDirectory(), locator.getBasePath());
}
return getHomeDirectory();
}
/**
* Gets the home directory. In this directory the strategy searches for files.
*
* @return The home directory used by this object.
*/
public String getHomeDirectory() {
return homeDirectory;
}
/**
* Returns a flag whether the base path is to be taken into account when searching for a file.
*
* @return The flag whether the base path is evaluated
*/
public boolean isEvaluateBasePath() {
return evaluateBasePath;
}
/**
* {@inheritDoc} This implementation searches in the home directory for a file described by the passed in
* {@code FileLocator}. If the locator defines a base path and the {@code evaluateBasePath} property is <strong>true</strong>, a
* sub directory of the home directory is searched.
*/
@Override
public URL locate(final FileSystem fileSystem, final FileLocator locator) {
if (StringUtils.isNotEmpty(locator.getFileName())) {
final String basePath = getBasePath(locator);
final File file = FileLocatorUtils.constructFile(basePath, locator.getFileName());
if (file.isFile()) {
return check(FileLocatorUtils.convertFileToURL(file));
}
}
return null;
}
}