CharSource

java.lang.Object
- com.google.common.io.CharSource

```
public abstract class CharSource
extends Object
```
A readable source of characters, such as a text file. Unlike a Reader, a CharSource is not an open, stateful stream of characters that can be read and closed. Instead, it is an immutable supplier of Reader instances.
CharSource provides two kinds of methods:
- Methods that return a reader: These methods should return a new, independent instance each time they are called. The caller is responsible for ensuring that the returned reader is closed.
- Convenience methods: These are implementations of common operations that are typically implemented by opening a reader using one of the methods in the first category, doing something and finally closing the reader that was opened.
Several methods in this class, such as readLines(), break the contents of the source into lines. Like BufferedReader, these methods break lines on any of \n, \r or \r\n, do not include the line separator in each line and do not consider there to be an empty line at the end if the contents are terminated with a line separator.

Any ByteSource containing text encoded with a specific character encoding may be viewed as a CharSource using ByteSource.asCharSource(Charset).
Since:

14.0

Constructor Summary

Constructors

Modifier	Constructor and Description
`protected`	`CharSource()` Constructor for use by subclasses.

Method Summary

All Methods

Static Methods

Instance Methods

Abstract Methods

Concrete Methods
Modifier and Type	Method and Description
`static CharSource`	`concat(CharSource... sources)` Concatenates multiple `CharSource` instances into a single source.
`static CharSource`	`concat(Iterable<? extends CharSource> sources)` Concatenates multiple `CharSource` instances into a single source.
`static CharSource`	`concat(Iterator<? extends CharSource> sources)` Concatenates multiple `CharSource` instances into a single source.
`long`	`copyTo(Appendable appendable)` Appends the contents of this source to the given `Appendable` (such as a `Writer`).
`long`	`copyTo(CharSink sink)` Copies the contents of this source to the given sink.
`static CharSource`	`empty()` Returns an immutable `CharSource` that contains no characters.
`boolean`	`isEmpty()` Returns whether the source has zero chars.
`BufferedReader`	`openBufferedStream()` Opens a new `BufferedReader` for reading from this source.
`abstract Reader`	`openStream()` Opens a new `Reader` for reading from this source.
`String`	`read()` Reads the contents of this source as a string.
`String`	`readFirstLine()` Reads the first link of this source as a string.
`ImmutableList<String>`	`readLines()` Reads all the lines of this source as a list of strings.
`<T> T`	`readLines(LineProcessor<T> processor)` Reads lines of text from this source, processing each line as it is read using the given `processor`.
`static CharSource`	`wrap(CharSequence charSequence)` Returns a view of the given character sequence as a `CharSource`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - CharSource
```
protected CharSource()
```
    Constructor for use by subclasses.
- Method Detail
  - openStream
```
public abstract Reader openStream()
                           throws IOException
```
    Opens a new Reader for reading from this source. This method should return a new, independent reader each time it is called.
    The caller is responsible for ensuring that the returned reader is closed.
    
    Throws:
    
    IOException - if an I/O error occurs in the process of opening the reader
  - openBufferedStream
```
public BufferedReader openBufferedStream()
                                  throws IOException
```
    Opens a new BufferedReader for reading from this source. This method should return a new, independent reader each time it is called.
    The caller is responsible for ensuring that the returned reader is closed.
    
    Throws:
    
    IOException - if an I/O error occurs in the process of opening the reader
  - copyTo
```
public long copyTo(Appendable appendable)
            throws IOException
```
    Appends the contents of this source to the given Appendable (such as a Writer). Does not close appendable if it is Closeable.
    
    Throws:
    
    IOException - if an I/O error occurs in the process of reading from this source or writing to appendable
  - copyTo
```
public long copyTo(CharSink sink)
            throws IOException
```
    Copies the contents of this source to the given sink.
    
    Throws:
    
    IOException - if an I/O error occurs in the process of reading from this source or writing to sink
  - read
```
public String read()
            throws IOException
```
    Reads the contents of this source as a string.
    
    Throws:
    
    IOException - if an I/O error occurs in the process of reading from this source
  - readFirstLine
```
public String readFirstLine()
                     throws IOException
```
    Reads the first link of this source as a string. Returns null if this source is empty.
    Like BufferedReader, this method breaks lines on any of \n, \r or \r\n, does not include the line separator in the returned line and does not consider there to be an extra empty line at the end if the content is terminated with a line separator.
    
    Throws:
    
    IOException - if an I/O error occurs in the process of reading from this source
  - readLines
```
public ImmutableList<String> readLines()
                                throws IOException
```
    Reads all the lines of this source as a list of strings. The returned list will be empty if this source is empty.
    Like BufferedReader, this method breaks lines on any of \n, \r or \r\n, does not include the line separator in the returned lines and does not consider there to be an extra empty line at the end if the content is terminated with a line separator.
    
    Throws:
    
    IOException - if an I/O error occurs in the process of reading from this source
  - readLines
```
@Beta
public <T> T readLines(LineProcessor<T> processor)
                      throws IOException
```
    Reads lines of text from this source, processing each line as it is read using the given processor. Stops when all lines have been processed or the processor returns false and returns the result produced by the processor.
    Like BufferedReader, this method breaks lines on any of \n, \r or \r\n, does not include the line separator in the lines passed to the processor and does not consider there to be an extra empty line at the end if the content is terminated with a line separator.
    
    Throws:
    
    IOException - if an I/O error occurs in the process of reading from this source or if processor throws an IOException
    
    Since:
    
    16.0
  - isEmpty
```
public boolean isEmpty()
                throws IOException
```
    Returns whether the source has zero chars. The default implementation is to open a stream and check for EOF.
    
    Throws:
    
    IOException - if an I/O error occurs
    
    Since:
    
    15.0
  - concat
```
public static CharSource concat(Iterable<? extends CharSource> sources)
```
    Concatenates multiple CharSource instances into a single source. Streams returned from the source will contain the concatenated data from the streams of the underlying sources.
    Only one underlying stream will be open at a time. Closing the concatenated stream will close the open underlying stream.
    
    Parameters:
    
    sources - the sources to concatenate
    
    Returns:
    
    a CharSource containing the concatenated data
    
    Since:
    
    15.0
  - concat
```
public static CharSource concat(Iterator<? extends CharSource> sources)
```
    Concatenates multiple CharSource instances into a single source. Streams returned from the source will contain the concatenated data from the streams of the underlying sources.
    Only one underlying stream will be open at a time. Closing the concatenated stream will close the open underlying stream.
    
    Note: The input Iterator will be copied to an ImmutableList when this method is called. This will fail if the iterator is infinite and may cause problems if the iterator eagerly fetches data for each source when iterated (rather than producing sources that only load data through their streams). Prefer using the concat(Iterable) overload if possible.
    
    Parameters:
    
    sources - the sources to concatenate
    
    Returns:
    
    a CharSource containing the concatenated data
    
    Throws:
    
    NullPointerException - if any of sources is null
    
    Since:
    
    15.0
  - concat
```
public static CharSource concat(CharSource... sources)
```
    Concatenates multiple CharSource instances into a single source. Streams returned from the source will contain the concatenated data from the streams of the underlying sources.
    Only one underlying stream will be open at a time. Closing the concatenated stream will close the open underlying stream.
    
    Parameters:
    
    sources - the sources to concatenate
    
    Returns:
    
    a CharSource containing the concatenated data
    
    Throws:
    
    NullPointerException - if any of sources is null
    
    Since:
    
    15.0
  - wrap
```
public static CharSource wrap(CharSequence charSequence)
```
    Returns a view of the given character sequence as a CharSource. The behavior of the returned CharSource and any Reader instances created by it is unspecified if the charSequence is mutated while it is being read, so don't do that.
    
    Since:
    
    15.0 (since 14.0 as CharStreams.asCharSource(String))
  - empty
```
public static CharSource empty()
```
    Returns an immutable CharSource that contains no characters.
    
    Since:
    
    15.0

Class CharSource

Constructor Summary

Constructors

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

CharSource

Method Detail

openStream

openBufferedStream

copyTo

copyTo

read

readFirstLine

readLines

readLines

isEmpty

concat

concat

concat

wrap

empty