stream.io.LineWriter Maven / Gradle / Ivy
/**
*
*/
package stream.io;
import java.io.File;
import java.io.FileOutputStream;
import java.io.PrintStream;
import stream.AbstractProcessor;
import stream.ProcessContext;
import stream.annotations.Description;
import stream.annotations.Parameter;
import stream.data.Data;
import stream.expressions.ExpressionResolver;
/**
* A simple output processor that writes out data items to a file according to
* some format string.
*
* @author Christian Bockermann <[email protected]>
*
*/
@Description(group = "Data Stream.Output")
public class LineWriter extends AbstractProcessor {
File file;
boolean append = false;
PrintStream out;
String format = null;
/**
* @return the file
*/
public File getFile() {
return file;
}
/**
* @param file
* the file to set
*/
@Parameter(required = true, description = "Name of the file to write to.")
public void setFile(File file) {
this.file = file;
}
/**
* @return the format
*/
public String getFormat() {
return format;
}
/**
* @param format
* the format to set
*/
@Parameter(required = true, description = "The format string, containing macros that are expanded for each item")
public void setFormat(String format) {
this.format = format;
}
/**
* @return the append
*/
public boolean isAppend() {
return append;
}
/**
* @param append
* the append to set
*/
@Parameter(required = false, description = "Denotes whether to append to existing files or create a new file at container startup.", defaultValue = "false")
public void setAppend(boolean append) {
this.append = append;
}
/**
* @see stream.AbstractProcessor#init(stream.ProcessContext)
*/
@Override
public void init(ProcessContext ctx) throws Exception {
super.init(ctx);
out = new PrintStream(new FileOutputStream(file, append));
}
/**
* @see stream.Processor#process(stream.data.Data)
*/
@Override
public Data process(Data input) {
if (input == null || format == null)
return input;
String line = ExpressionResolver.expand(format, context, input);
while (line.indexOf("\n") >= 0) {
line = line.replace("\n", "\\n");
}
out.println(line);
return input;
}
/**
* @see stream.AbstractProcessor#finish()
*/
@Override
public void finish() throws Exception {
super.finish();
}
}