Inputs.java
/*
* Copyright (c) 2010, Rickard Öberg. All Rights Reserved.
*
* Licensed 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.qi4j.io;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.Reader;
import java.net.URL;
import java.net.URLConnection;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.Scanner;
import java.util.zip.GZIPInputStream;
import org.qi4j.functional.Visitor;
/**
* Common inputs
*/
public class Inputs
{
// START SNIPPET: method
/**
* Read lines from a String.
*
* @param source lines
*
* @return Input that provides lines from the string as strings
*/
public static Input<String, RuntimeException> text( final String source )
// END SNIPPET: method
{
return new Input<String, RuntimeException>()
{
@Override
public <ReceiverThrowableType extends Throwable> void transferTo( Output<? super String, ReceiverThrowableType> output )
throws RuntimeException, ReceiverThrowableType
{
output.receiveFrom( new Sender<String, RuntimeException>()
{
@Override
public <Receiver2ThrowableType extends Throwable> void sendTo( Receiver<? super String, Receiver2ThrowableType> receiver )
throws Receiver2ThrowableType, RuntimeException
{
Scanner scanner = new Scanner( source );
while( scanner.hasNextLine() )
{
receiver.receive( scanner.nextLine() );
}
}
} );
}
};
}
// START SNIPPET: method
/**
* Read lines from a Reader.
*
* @param source lines
*
* @return Input that provides lines from the string as strings
*/
public static Input<String, RuntimeException> text( final Reader source )
// END SNIPPET: method
{
return new Input<String, RuntimeException>()
{
@Override
public <ReceiverThrowableType extends Throwable> void transferTo( Output<? super String, ReceiverThrowableType> output )
throws RuntimeException, ReceiverThrowableType
{
output.receiveFrom( new Sender<String, RuntimeException>()
{
@Override
public <Receiver2ThrowableType extends Throwable> void sendTo( Receiver<? super String, Receiver2ThrowableType> receiver )
throws Receiver2ThrowableType, RuntimeException
{
Scanner scanner = new Scanner( source );
while( scanner.hasNextLine() )
{
receiver.receive( scanner.nextLine() );
}
}
} );
}
};
}
// START SNIPPET: method
/**
* Read lines from a UTF-8 encoded textfile.
*
* If the filename ends with .gz, then the data is automatically unzipped when read.
*
* @param source textfile with lines separated by \n character
*
* @return Input that provides lines from the textfiles as strings
*/
public static Input<String, IOException> text( final File source )
// END SNIPPET: method
{
return text( source, "UTF-8" );
}
// START SNIPPET: method
/**
* Read lines from a textfile with the given encoding.
*
* If the filename ends with .gz, then the data is automatically unzipped when read.
*
* @param source textfile with lines separated by \n character
* @param encoding encoding of file, e.g. "UTF-8"
*
* @return Input that provides lines from the textfiles as strings
*/
public static Input<String, IOException> text( final File source, final String encoding )
// END SNIPPET: method
{
return new Input<String, IOException>()
{
@Override
public <ReceiverThrowableType extends Throwable> void transferTo( Output<? super String, ReceiverThrowableType> output )
throws IOException, ReceiverThrowableType
{
InputStream stream = new FileInputStream( source );
// If file is gzipped, unzip it automatically
if( source.getName().endsWith( ".gz" ) )
{
stream = new GZIPInputStream( stream );
}
try (BufferedReader reader = new BufferedReader( new InputStreamReader( stream, encoding ) ))
{
output.receiveFrom( new Sender<String, IOException>()
{
@Override
public <Receiver2ThrowableType extends Throwable> void sendTo( Receiver<? super String, Receiver2ThrowableType> receiver )
throws Receiver2ThrowableType, IOException
{
String line;
while( ( line = reader.readLine() ) != null )
{
receiver.receive( line );
}
}
} );
}
}
};
}
// START SNIPPET: method
/**
* Read lines from a textfile at a given URL.
*
* If the content support gzip encoding, then the data is automatically unzipped when read.
*
* The charset in the content-type of the URL will be used for parsing. Default is UTF-8.
*
* @param source textfile with lines separated by \n character
*
* @return Input that provides lines from the textfiles as strings
*/
public static Input<String, IOException> text( final URL source )
// END SNIPPET: method
{
return new Input<String, IOException>()
{
@Override
public <ReceiverThrowableType extends Throwable> void transferTo( Output<? super String, ReceiverThrowableType> output )
throws IOException, ReceiverThrowableType
{
URLConnection urlConnection = source.openConnection();
urlConnection.setRequestProperty( "Accept-Encoding", "gzip" );
InputStream stream = urlConnection.getInputStream();
// If file is gzipped, unzip it automatically
if( "gzip".equals( urlConnection.getContentEncoding() ) )
{
stream = new GZIPInputStream( stream );
}
// Figure out charset given content-type
String contentType = urlConnection.getContentType();
String charSet = "UTF-8";
if( contentType.contains( "charset=" ) )
{
charSet = contentType.substring( contentType.indexOf( "charset=" ) + "charset=".length() );
}
try (BufferedReader reader = new BufferedReader( new InputStreamReader( stream, charSet ) ))
{
output.receiveFrom( new Sender<String, IOException>()
{
@Override
public <Receiver2ThrowableType extends Throwable> void sendTo( Receiver<? super String, Receiver2ThrowableType> receiver )
throws Receiver2ThrowableType, IOException
{
String line;
while( ( line = reader.readLine() ) != null )
{
receiver.receive( line );
}
}
} );
}
}
};
}
// START SNIPPET: method
/**
* Read a file using ByteBuffer of a given size. Useful for transferring raw data.
*
* @param source The file to be read.
* @param bufferSize The size of the byte array.
*
* @return An Input instance to be applied to streaming operations.
*/
public static Input<ByteBuffer, IOException> byteBuffer( final File source, final int bufferSize )
// END SNIPPET: method
{
return new Input<ByteBuffer, IOException>()
{
@Override
public <ReceiverThrowableType extends Throwable> void transferTo( Output<? super ByteBuffer, ReceiverThrowableType> output )
throws IOException, ReceiverThrowableType
{
final FileInputStream stream = new FileInputStream( source );
final FileChannel fci = stream.getChannel();
final ByteBuffer buffer = ByteBuffer.allocate( bufferSize );
try
{
output.receiveFrom( new Sender<ByteBuffer, IOException>()
{
@Override
public <Receiver2ThrowableType extends Throwable> void sendTo( Receiver<? super ByteBuffer, Receiver2ThrowableType> receiver )
throws Receiver2ThrowableType, IOException
{
while( fci.read( buffer ) != -1 )
{
buffer.flip();
receiver.receive( buffer );
buffer.clear();
}
}
} );
}
finally
{
stream.close();
}
}
};
}
// START SNIPPET: method
/**
* Read an inputstream using ByteBuffer of a given size.
*
* @param source The InputStream to be read.
* @param bufferSize The size of the byte array.
*
* @return An Input instance to be applied to streaming operations.
*/
public static Input<ByteBuffer, IOException> byteBuffer( final InputStream source, final int bufferSize )
// END SNIPPET: method
{
return new Input<ByteBuffer, IOException>()
{
@Override
public <ReceiverThrowableType extends Throwable> void transferTo( Output<? super ByteBuffer, ReceiverThrowableType> output )
throws IOException, ReceiverThrowableType
{
try
{
output.receiveFrom( new Sender<ByteBuffer, IOException>()
{
@Override
public <Receiver2ThrowableType extends Throwable> void sendTo( Receiver<? super ByteBuffer, Receiver2ThrowableType> receiver )
throws Receiver2ThrowableType, IOException
{
byte[] buffer = new byte[ bufferSize ];
int len;
while( ( len = source.read( buffer ) ) != -1 )
{
ByteBuffer byteBuffer = ByteBuffer.wrap( buffer, 0, len );
receiver.receive( byteBuffer );
}
}
} );
}
finally
{
source.close();
}
}
};
}
// START SNIPPET: method
/**
* Combine many Input into one single Input. When a transfer is initiated from it all items from all inputs will be transferred
* to the given Output.
*
* @param inputs An Iterable of Input instances to be combined.
* @param <T> The item type of the Input
* @param <SenderThrowableType> The Throwable that might be thrown by the Inputs.
*
* @return A combined Input, allowing for easy aggregation of many Input sources.
*/
public static <T, SenderThrowableType extends Throwable> Input<T, SenderThrowableType> combine( final Iterable<Input<T, SenderThrowableType>> inputs )
// END SNIPPET: method
{
return new Input<T, SenderThrowableType>()
{
@Override
public <Receiver2ThrowableType extends Throwable> void transferTo( Output<? super T, Receiver2ThrowableType> output )
throws SenderThrowableType, Receiver2ThrowableType
{
output.receiveFrom( new Sender<T, SenderThrowableType>()
{
@Override
public <ReceiverThrowableType extends Throwable> void sendTo( final Receiver<? super T, ReceiverThrowableType> receiver )
throws ReceiverThrowableType, SenderThrowableType
{
for( Input<T, SenderThrowableType> input : inputs )
{
input.transferTo( new Output<T, ReceiverThrowableType>()
{
@Override
public <Sender2ThrowableType extends Throwable> void receiveFrom( Sender<? extends T, Sender2ThrowableType> sender )
throws ReceiverThrowableType, Sender2ThrowableType
{
sender.sendTo( new Receiver<T, ReceiverThrowableType>()
{
@Override
public void receive( T item )
throws ReceiverThrowableType
{
receiver.receive( item );
}
} );
}
} );
}
}
} );
}
};
}
// START SNIPPET: method
/**
* Create an Input that takes its items from the given Iterable.
*
* @param iterable The Iterable to be used as an Input.
* @param <T> The item type of the Input
*
* @return An Input instance that is backed by the Iterable.
*/
public static <T> Input<T, RuntimeException> iterable( final Iterable<T> iterable )
// END SNIPPET: method
{
return new Input<T, RuntimeException>()
{
@Override
public <ReceiverThrowableType extends Throwable> void transferTo( Output<? super T, ReceiverThrowableType> output )
throws RuntimeException, ReceiverThrowableType
{
output.receiveFrom( new Sender<T, RuntimeException>()
{
@Override
public <Receiver2ThrowableType extends Throwable> void sendTo( Receiver<? super T, Receiver2ThrowableType> receiver )
throws Receiver2ThrowableType, RuntimeException
{
for( T item : iterable )
{
receiver.receive( item );
}
}
} );
}
};
}
// START SNIPPET: method
/**
* Create an Input that allows a Visitor to write to an OutputStream. The stream is a BufferedOutputStream, so when enough
* data has been gathered it will send this in chunks of the given size to the Output it is transferred to. The Visitor does not have to call
* close() on the OutputStream, but should ensure that any wrapper streams or writers are flushed so that all data is sent.
*
* @param outputVisitor The OutputStream Visitor that will be backing the Input ByteBuffer.
* @param bufferSize The buffering size.
*
* @return An Input instance of ByteBuffer, that is backed by an Visitor to an OutputStream.
*/
public static Input<ByteBuffer, IOException> output( final Visitor<OutputStream, IOException> outputVisitor,
final int bufferSize
)
// END SNIPPET: method
{
return new Input<ByteBuffer, IOException>()
{
@Override
public <ReceiverThrowableType extends Throwable> void transferTo( Output<? super ByteBuffer, ReceiverThrowableType> output )
throws IOException, ReceiverThrowableType
{
output.receiveFrom( new Sender<ByteBuffer, IOException>()
{
@Override
@SuppressWarnings( "unchecked" )
public <Receiver2ThrowableType extends Throwable> void sendTo( final Receiver<? super ByteBuffer, Receiver2ThrowableType> receiver )
throws Receiver2ThrowableType, IOException
{
try (OutputStream out = new BufferedOutputStream( new OutputStream()
{
@Override
public void write( int b )
throws IOException
{
// Ignore
}
@SuppressWarnings( "NullableProblems" )
@Override
public void write( byte[] b, int off, int len )
throws IOException
{
try
{
ByteBuffer byteBuffer = ByteBuffer.wrap( b, 0, len );
receiver.receive( byteBuffer );
}
catch( Throwable ex )
{
throw new IOException( ex );
}
}
}, bufferSize ))
{
outputVisitor.visit( out );
}
catch( IOException ex )
{
throw (Receiver2ThrowableType) ex.getCause();
}
}
} );
}
};
}
private Inputs()
{
}
}