Package com.github.javinator9889.exporter

Class FileToBytesExporter

java.lang.Object

com.github.javinator9889.exporter.FileToBytesExporter

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public class FileToBytesExporter
extends java.lang.Object
implements java.lang.Cloneable, java.io.Serializable

Files to bytes exporter provides a custom, fast class for generating binary files from plain (or not) text files.

Binary files are present at every computer and the have some interesting advantages facing regular text files:

• Memory efficient: while plain text files has 128 possible values (pure unexpanded ASCII), binary files have up to 256 possible values, so it is twice compact (as for representing some chars in ASCII, more than one value is needed).
• Compact: storing a binary file will necessarily be more packed than a plain text file.
• No syntax definition: as some human-readable files such as XML, JAVA, etc . need a specific syntax for saving data correctly, they increase its size and complexity with that rules. As opposed to that, binary files just saves the data, with no modifications or rules, which is faster and memory friendly.
• Directly to memory: as there is no need of processing the data, reading a binary file is as simple as it goes directly to the memory for using it.
• Secure: as binary file is not human-readable file, it makes impossible to others to inspect and know the file contents without a proper editor. Also they need to know which type of data structure is saved for obtaining the desired instance.

This class allows you to easily generate binary files from regular text files with some simple methods and attributes. In addition, it supports glob syntax, so it is even easier to find and convert lots of files with just one line.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	FileToBytesExporter.Glob	Class for searching and obtaining files that corresponds to a custom glob.
private static class	FileToBytesExporter.Lock	Private custom class for synchronizing monitor locks.

Field Summary

Fields

Modifier and Type	Field	Description
private java.lang.Object	lock
private java.lang.String	mFilename
private java.lang.String	mFileSeparator
private boolean	mMustOpenSourcePath
private java.util.ArrayList<java.lang.String>	mPath
private java.lang.String	mReadData

Constructor Summary

Constructors

Modifier	Constructor	Description
	FileToBytesExporter()	Public default constructor - sets filename to null and path to empty String array.
	FileToBytesExporter(java.lang.String filename)	Constructor that uses only the filename as argument (path is an empty array).
	FileToBytesExporter(java.lang.String filename, boolean mustOpenSourcePath, java.lang.String... paths)	Constructor that uses an extra attribute for declaring whether or not the source path will be used also for searching the file.
	FileToBytesExporter(java.lang.String filename, java.lang.String... paths)	Constructor that uses both filename and path as arguments.
private	FileToBytesExporter(java.lang.String filename, java.util.ArrayList<java.lang.String> paths, java.lang.String readData, java.lang.String fileSeparator, boolean mustOpenSourcePath)	Private constructor for cloning or generating a new instance - only visible for this class.

Method Summary

Modifier and Type	Method	Description
void	addPath(java.lang.String newPath)	Includes a new path inside the stored paths - if path is not created, it generates a new instance by using setPaths(String...) method.
protected java.lang.Object	clone()	Creates and returns a copy of this object.
boolean	equals(java.lang.Object o)	Indicates whether some other object is "equal to" this one.
java.lang.String	getFileSeparator()	Obtains the file separator used when writing/reading the files - can be null if only one file was read/written
protected static java.lang.String	getHash(java.lang.String source)	Obtains the hash of the specified source by using MessageDigest.digest(byte[]) method, generating a SHA-256 hash.
java.lang.String	getReadData()	Obtains all the read data obtained after executing readSource() methods
int	hashCode()	Returns a hash code value for the object.
void	readObject(java.io.File source)	Reads the data contained at source obtaining its file separator (used if more than one file was read) and the file data.
void	readObject(java.io.InputStream source)	Reads the data contained at source obtaining its file separator (used if more than one file was read) and the file data.
void	readSource()	Reads the source file and saves its contents inside a String object.
void	readSource(boolean mustOpenAllFiles)	Reads all the sources file that were found at the current paths and inside all the provided paths if mustOpenAllFiles is true, appending every file at the end with a double blank line.
void	readSource(boolean mustOpenAllFiles, java.lang.String fileSeparator)	Reads all the sources file that were found at the current paths and inside all the provided paths if mustOpenAllFiles is true, appending every file at the end the value passed at fileSeparator.
static java.lang.String	readSource(java.io.File source)	Reads the provided file and returns the String that contains its content.
void	setFilename(java.lang.String filename)	Updates the filename once the class is created
void	setMustOpenSourcePath(boolean mustOpenSourcePath)	Updates the policy for reading also the source directory for the provided filename.
void	setPaths(java.lang.String... paths)	Updates the paths once the class is created
java.lang.String	toString()	Returns a string representation of the object.
void	writeObject(java.io.File destination)	Writes the read object to the specified destination given at destination.
void	writeObject(java.io.OutputStream destination)	Writes the read object to the specified destination given at destination.
static void	writeObject(java.lang.String source, java.io.File destination)	Writes the read object to the specified destination given at destination.
static void	writeObject(java.lang.String source, java.io.OutputStream destination)	Writes the read object to the specified destination given at destination.

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

mFilename

private java.lang.String mFilename

mPath

private java.util.ArrayList<java.lang.String> mPath

mReadData

private java.lang.String mReadData

mFileSeparator

private java.lang.String mFileSeparator

mMustOpenSourcePath

private boolean mMustOpenSourcePath

lock

private final java.lang.Object lock

Constructor Detail

FileToBytesExporter

public FileToBytesExporter()

Public default constructor - sets filename to null and path to empty String array.

See Also:

String

FileToBytesExporter

public FileToBytesExporter(java.lang.String filename)

Constructor that uses only the filename as argument (path is an empty array).

Parameters:

filename - source file.

See Also:

String

FileToBytesExporter

public FileToBytesExporter(java.lang.String filename,
                           java.lang.String... paths)

Constructor that uses both filename and path as arguments.

Parameters:

filename - source file.

paths - list of paths where to search for the source file.

See Also:

String

FileToBytesExporter

public FileToBytesExporter(java.lang.String filename,
                           boolean mustOpenSourcePath,
                           java.lang.String... paths)

Constructor that uses an extra attribute for declaring whether or not the source path will be used also for searching the file.

Parameters:

filename - source file.

mustOpenSourcePath - true if the source path is included while reading the file.

paths - list of paths where to search for the source file.

FileToBytesExporter

private FileToBytesExporter(java.lang.String filename,
                            java.util.ArrayList<java.lang.String> paths,
                            java.lang.String readData,
                            java.lang.String fileSeparator,
                            boolean mustOpenSourcePath)

Private constructor for cloning or generating a new instance - only visible for this class.

Parameters:

filename - source file.

paths - list of paths where search for the source file.

readData - current read data.

fileSeparator - current used file separator.

mustOpenSourcePath - whether the source path should be used for searching files.

Method Detail

setFilename

public void setFilename(java.lang.String filename)

Updates the filename once the class is created

Parameters:

filename - new filename

setPaths

public void setPaths(java.lang.String... paths)

Updates the paths once the class is created

Parameters:

paths - new paths

setMustOpenSourcePath

public void setMustOpenSourcePath(boolean mustOpenSourcePath)

Updates the policy for reading also the source directory for the provided filename.

Parameters:

mustOpenSourcePath - whether the source directory is used or not.

addPath

public void addPath(java.lang.String newPath)

Includes a new path inside the stored paths - if path is not created, it generates a new instance by using setPaths(String...) method.

Parameters:

newPath - new path to include

readSource

public void readSource()
                throws java.io.IOException

Reads the source file and saves its contents inside a String object.

Throws:

MultipleFilesFoundError - if multiple files were found and mustOpenAllFiles is false.

InvalidPathException - when one of the provided paths does not exists or any other error happened (like having not enough permissions).

java.io.FileNotFoundException - when the filename is not found at any of the directories.

java.io.IOException

readSource

public void readSource(boolean mustOpenAllFiles)
                throws java.io.IOException

Reads all the sources file that were found at the current paths and inside all the provided paths if mustOpenAllFiles is true, appending every file at the end with a double blank line.

Parameters:

mustOpenAllFiles - whether if more than one source file was found it must be also read and appended at the end of the current file.

Throws:

MultipleFilesFoundError - if multiple files were found and mustOpenAllFiles is false.

InvalidPathException - when one of the provided paths does not exists or any other error happened (like having not enough permissions).

java.io.FileNotFoundException - when the filename is not found at any of the directories.

java.io.IOException

readSource

public void readSource(boolean mustOpenAllFiles,
                       java.lang.String fileSeparator)
                throws java.io.IOException

Reads all the sources file that were found at the current paths and inside all the provided paths if mustOpenAllFiles is true, appending every file at the end the value passed at fileSeparator.

Parameters:

mustOpenAllFiles - whether if more than one source file was found it must be also read and appended at the end of the current file. In addition, if is set to true, it will navigate through all the child directories for file matches with the same name - pattern specified at FileToBytesExporter(String) or setFilename(String).

fileSeparator - the String that will be added at the end of the just read file if any other file was found.

Throws:

MultipleFilesFoundError - if multiple files were found and mustOpenAllFiles is false.

InvalidFileSeparatorException - when multiple files were found and fileSeparator is null.

InvalidPathException - when one of the provided paths does not exists or any other error happened (like having not enough permissions).

java.io.FileNotFoundException - when the filename is not found at any of the directories.

java.io.IOException - when looking for a file using glob and any error occurred

See Also:

FileToBytesExporter.Glob.match(File, String, boolean)

readSource

public static java.lang.String readSource(java.io.File source)
                                   throws java.io.IOException

Reads the provided file and returns the String that contains its content.

Parameters:

source - the file that will be read.

Returns:

String with the file data.

Throws:

java.io.IOException - if the file does not exists or there is any error while reading it.

getReadData

public java.lang.String getReadData()

Obtains all the read data obtained after executing readSource() methods

Returns:

String with the data

getFileSeparator

public java.lang.String getFileSeparator()

Obtains the file separator used when writing/reading the files - can be null if only one file was read/written

Returns:

String with the file separator

writeObject

public void writeObject(java.io.File destination)
                 throws java.io.IOException

Writes the read object to the specified destination given at destination. If it does not exists, com.github.javinator9889.exporter.FileToBytesExporter will create all the necessary directories in order to work as expected.

Parameters:

destination - relative or complete path to the output file - cannot be only dir.

Throws:

java.io.IOException - when there is an error by creating necessary directories or by writing the file.

writeObject

public void writeObject(java.io.OutputStream destination)
                 throws java.io.IOException

Writes the read object to the specified destination given at destination. If it does not exists, com.github.javinator9889.exporter.FileToBytesExporter will create all the necessary directories in order to work as expected.

Parameters:

destination - subclass of OutputStream which contains the output file that can be used at ObjectOutputStream constructor (e.g.: FileOutputStream).

Throws:

java.io.IOException - when there is an error while writing the file.

writeObject

public static void writeObject(java.lang.String source,
                               java.io.File destination)
                        throws java.io.IOException

Writes the read object to the specified destination given at destination. If it does not exists, com.github.javinator9889.exporter.FileToBytesExporter will create all the necessary directories in order to work as expected.

Parameters:

source - the source that will be wrote to the destination - use readSource(File) for obtaining the data.

destination - relative or complete path to the output file - cannot be only dir.

Throws:

java.io.IOException - when there is an error by creating necessary directories or by writing the file.

writeObject

public static void writeObject(java.lang.String source,
                               java.io.OutputStream destination)
                        throws java.io.IOException

Writes the read object to the specified destination given at destination. If it does not exists, com.github.javinator9889.exporter.FileToBytesExporter will create all the necessary directories in order to work as expected.

Parameters:

source - the source that will be wrote to the destination - use readSource(File) for obtaining the data.

destination - subclass of OutputStream which contains the output file that can be used at ObjectOutputStream constructor (e.g.: FileOutputStream).

Throws:

java.io.IOException - when there is an error while writing the file.

readObject

public void readObject(java.io.File source)
                throws java.io.IOException,
                       java.lang.ClassCastException

Reads the data contained at source obtaining its file separator (used if more than one file was read) and the file data. Both file separator and data can be obtained by using getFileSeparator() and getReadData()

Parameters:

source - relative or complete path to the file - cannot be only a directory

Throws:

java.io.IOException - if the file was not found, there was an error recovering the data or it is a directory.

java.lang.ClassCastException - if the retrieved data is not a String[]

FileError - if the obtained hash from file is not the same as the generated one from the data extracted from the file.

readObject

public void readObject(java.io.InputStream source)
                throws java.io.IOException,
                       java.lang.ClassCastException

Reads the data contained at source obtaining its file separator (used if more than one file was read) and the file data. Both file separator and data can be obtained by using getFileSeparator() and getReadData()

Parameters:

source - InputStream subclass that can be used at ObjectInputStream(InputStream) constructor (e.g.: FileInputStream).

Throws:

java.io.IOException - if there was an error recovering the data.

java.lang.ClassCastException - if the retrieved data is not a String[]

FileError - if the obtained hash from file is not the same as the generated one from the data extracted from the file.

getHash

protected static java.lang.String getHash(java.lang.String source)

Obtains the hash of the specified source by using MessageDigest.digest(byte[]) method, generating a SHA-256 hash. If it fails because no SHA-256 hashing algorithm was found, it just returns the String.hashCode() casted to String.

You can @Override this method if you inherit from FileToBytesExporter if you need any other StandardCharsets charset.

Parameters:

source - original String where obtaining bytes from.

Returns:

String with the SHA-256 hash of source.

equals

public boolean equals(java.lang.Object o)

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

• It is reflexive: for any non-null reference value x, x.equals(x) should return true.
• It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
• It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
• It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
• For any non-null reference value x, x.equals(null) should return false.

The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

Overrides:

equals in class java.lang.Object

Parameters:

o - the reference object with which to compare.

Returns:

true if this object is the same as the obj argument; false otherwise.

See Also:

hashCode(), HashMap

hashCode

public int hashCode()

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by HashMap.

The general contract of hashCode is:

• Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
• If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
• It is not required that if two objects are unequal according to the Object.equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (The hashCode may or may not be implemented as some function of an object's memory address at some point in time.)

Overrides:

hashCode in class java.lang.Object

Returns:

a hash code value for this object.

See Also:

Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

clone

protected java.lang.Object clone()

Creates and returns a copy of this object. The precise meaning of "copy" may depend on the class of the object. The general intent is that, for any object x, the expression:

 x.clone() != x

will be true, and that the expression:

 x.clone().getClass() == x.getClass()

will be true, but these are not absolute requirements. While it is typically the case that:

 x.clone().equals(x)

will be true, this is not an absolute requirement.

By convention, the returned object should be obtained by calling super.clone. If a class and all of its superclasses (except Object) obey this convention, it will be the case that x.clone().getClass() == x.getClass().

By convention, the object returned by this method should be independent of this object (which is being cloned). To achieve this independence, it may be necessary to modify one or more fields of the object returned by super.clone before returning it. Typically, this means copying any mutable objects that comprise the internal "deep structure" of the object being cloned and replacing the references to these objects with references to the copies. If a class contains only primitive fields or references to immutable objects, then it is usually the case that no fields in the object returned by super.clone need to be modified.

The method clone for class Object performs a specific cloning operation. First, if the class of this object does not implement the interface Cloneable, then a CloneNotSupportedException is thrown. Note that all arrays are considered to implement the interface Cloneable and that the return type of the clone method of an array type T[] is T[] where T is any reference or primitive type. Otherwise, this method creates a new instance of the class of this object and initializes all its fields with exactly the contents of the corresponding fields of this object, as if by assignment; the contents of the fields are not themselves cloned. Thus, this method performs a "shallow copy" of this object, not a "deep copy" operation.

The class Object does not itself implement the interface Cloneable, so calling the clone method on an object whose class is Object will result in throwing an exception at run time.

Overrides:

clone in class java.lang.Object

Returns:

a clone of this instance.

See Also:

Cloneable

toString

public java.lang.String toString()

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

Overrides:

toString in class java.lang.Object

Returns:

a string representation of the object.