org.apache.commons.configuration2.io.FileLocator Maven / Gradle / Ivy
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Tools to assist in the reading of configuration/preferences files in
various formats
/*
* 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.commons.configuration2.io;
import java.net.URL;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.HashCodeBuilder;
import org.apache.commons.lang3.builder.ToStringBuilder;
/**
*
* A class describing the location of a file.
*
*
* An instance of this class provides information for locating and accessing a
* file. The file location can be defined
*
*
* - as a URL; this identifies a file in a unique way
* - as a combination of base path and file name; if this variant is used,
* there may be an additional location step required in order to identify the
* referenced file (for instance, the file name may be interpreted as the name
* of a resource to be loaded from class path).
*
*
* In addition, other properties are available which are also needed for loading
* or saving a file, like the underlying {@link FileSystem}. The encoding to be
* used when accessing the represented data is also part of the data contained
* in an instance; if no encoding is set explicitly, the platform's default
* encoding is used.
*
* Instances of this class are immutable and thus can be safely shared between
* arbitrary components. {@link FileHandler} also uses an instance to reference
* the associated file. Instances are created using a builder.
* {@link FileLocatorUtils} offers convenience methods for obtaining such a
* builder.
*
*
* @since 2.0
*/
public final class FileLocator
{
/** The file name. */
private final String fileName;
/** The base path. */
private final String basePath;
/** The source URL. */
private final URL sourceURL;
/** The encoding. */
private final String encoding;
/** The file system. */
private final FileSystem fileSystem;
/** The file location strategy. */
private final FileLocationStrategy locationStrategy;
/**
* Creates a new instance of {@code FileLocatorImpl} and initializes it from
* the given builder instance
*
* @param builder the builder
*/
public FileLocator(final FileLocatorBuilder builder)
{
fileName = builder.fileName;
basePath = builder.basePath;
sourceURL = builder.sourceURL;
encoding = builder.encoding;
fileSystem = builder.fileSystem;
locationStrategy = builder.locationStrategy;
}
/**
* Returns the file name stored in this locator or null if it is
* undefined.
*
* @return the file name
*/
public String getFileName()
{
return fileName;
}
/**
* Returns the base path stored in this locator or null if it is
* undefined.
*
* @return the base path
*/
public String getBasePath()
{
return basePath;
}
/**
* Returns the URL pointing to the referenced source file or null if
* it is undefined.
*
* @return the source URL
*/
public URL getSourceURL()
{
return sourceURL;
}
/**
* Returns the encoding stored in this locator or null if it is
* undefined.
*
* @return the encoding
*/
public String getEncoding()
{
return encoding;
}
/**
* Returns the {@code FileSystem} to be used for accessing the file
* referenced by this locator or null if it is undefined.
*
* @return the {@code FileSystem}
*/
public FileSystem getFileSystem()
{
return fileSystem;
}
/**
* Returns the {@code FileLocationStrategy} to be used for locating the
* referenced file. If no specific {@code FileLocationStrategy} has been
* set, result is null. This means that the default strategy should
* be used.
*
* @return the {@code FileLocationStrategy} to be used
*/
public FileLocationStrategy getLocationStrategy()
{
return locationStrategy;
}
/**
* Returns a hash code for this object.
*
* @return a hash code for this object
*/
@Override
public int hashCode()
{
return new HashCodeBuilder().append(getFileName())
.append(getBasePath()).append(sourceURLAsString())
.append(getEncoding()).append(getFileSystem())
.append(getLocationStrategy()).toHashCode();
}
/**
* Compares this object with another one. Two instances of
* {@code FileLocatorImpl} are considered equal if all of their properties
* are equal.
*
* @param obj the object to compare to
* @return a flag whether these objects are equal
*/
@Override
public boolean equals(final Object obj)
{
if (this == obj)
{
return true;
}
if (!(obj instanceof FileLocator))
{
return false;
}
final FileLocator c = (FileLocator) obj;
return new EqualsBuilder().append(getFileName(), c.getFileName())
.append(getBasePath(), c.getBasePath())
.append(sourceURLAsString(), c.sourceURLAsString())
.append(getEncoding(), c.getEncoding())
.append(getFileSystem(), c.getFileSystem())
.append(getLocationStrategy(), c.getLocationStrategy())
.isEquals();
}
/**
* Returns a string representation of this object. This string contains the
* values of all properties.
*
* @return a string for this object
*/
@Override
public String toString()
{
return new ToStringBuilder(this).append("fileName", getFileName())
.append("basePath", getBasePath())
.append("sourceURL", sourceURLAsString())
.append("encoding", getEncoding())
.append("fileSystem", getFileSystem())
.append("locationStrategy", getLocationStrategy()).toString();
}
/**
* Returns the source URL as a string. Result is never null. Comparisons are
* done on this string to avoid blocking network calls.
*
* @return the source URL as a string (not null)
*/
private String sourceURLAsString()
{
return sourceURL != null ? sourceURL.toExternalForm()
: StringUtils.EMPTY;
}
/**
* A typical builder implementation for creating
* {@code FileLocator} objects. An instance of this class is returned by the
* {@code fileLocator()} method of {link FileLocatorUtils}. It can be used
* to define the various components of the {@code FileLocator} object. By
* calling {@code create()} the new immutable {@code FileLocator} instance
* is created.
*/
public static final class FileLocatorBuilder
{
/** The file name. */
private String fileName;
/** The base path. */
private String basePath;
/** The source URL. */
private URL sourceURL;
/** The encoding. */
private String encoding;
/** The file system. */
private FileSystem fileSystem;
/** The location strategy. */
private FileLocationStrategy locationStrategy;
/**
* Creates a new instance of {@code FileLocatorBuilder} and initializes
* the builder's properties from the passed in {@code FileLocator}
* object.
*
* @param src the source {@code FileLocator} (may be null)
*/
FileLocatorBuilder(final FileLocator src)
{
if (src != null)
{
initBuilder(src);
}
}
/**
* Specifies the encoding of the new {@code FileLocator}.
*
* @param enc the encoding
* @return a reference to this builder for method chaining
*/
public FileLocatorBuilder encoding(final String enc)
{
encoding = enc;
return this;
}
/**
* Specifies the {@code FileSystem} of the new {@code FileLocator}.
*
* @param fs the {@code FileSystem}
* @return a reference to this builder for method chaining
*/
public FileLocatorBuilder fileSystem(final FileSystem fs)
{
fileSystem = fs;
return this;
}
/**
* Specifies the base path of the new {@code FileLocator}.
*
* @param path the base path
* @return a reference to this builder for method chaining
*/
public FileLocatorBuilder basePath(final String path)
{
basePath = path;
return this;
}
/**
* Specifies the file name of the new {@code FileLocator}.
*
* @param name the file name
* @return a reference to this builder for method chaining
*/
public FileLocatorBuilder fileName(final String name)
{
fileName = name;
return this;
}
/**
* Specifies the source URL of the new {@code FileLocator}.
*
* @param url the source URL
* @return a reference to this builder for method chaining
*/
public FileLocatorBuilder sourceURL(final URL url)
{
sourceURL = url;
return this;
}
/**
* Specifies the {@code FileLocationStrategy} to be used when the
* referenced file is to be located.
*
* @param strategy the {@code FileLocationStrategy}
* @return a reference to this builder for method chaining
*/
public FileLocatorBuilder locationStrategy(final FileLocationStrategy strategy)
{
locationStrategy = strategy;
return this;
}
/**
* Creates a new immutable {@code FileLocatorImpl} object based on the
* properties set so far for this builder.
*
* @return the newly created {@code FileLocator} object
*/
public FileLocator create()
{
return new FileLocator(this);
}
/**
* Initializes the properties of this builder from the passed in locator
* object.
*
* @param src the source {@code FileLocator}
*/
private void initBuilder(final FileLocator src)
{
basePath = src.getBasePath();
fileName = src.getFileName();
sourceURL = src.getSourceURL();
encoding = src.getEncoding();
fileSystem = src.getFileSystem();
locationStrategy = src.getLocationStrategy();
}
}
}