AbstractRecordingTableImportEventHandler.java

package fr.openwide.core.imports.table.common.event;

import fr.openwide.core.imports.table.common.event.TableImportEvent.ExcelImportErrorEvent;
import fr.openwide.core.imports.table.common.event.TableImportEvent.ExcelImportInfoEvent;
import fr.openwide.core.imports.table.common.event.exception.TableImportContentException;
import fr.openwide.core.imports.table.common.event.exception.TableImportHeaderLabelMappingException;
import fr.openwide.core.imports.table.common.event.exception.TableImportMappingException;
import fr.openwide.core.imports.table.common.event.formatter.ITableImportEventMessageFormatter;
import fr.openwide.core.imports.table.common.location.TableImportLocation;

/**
 * A event handler that will record errors to an external sink, and may delay exception throwing until {@link #checkNoErrorOccurred()} is called.
 * <p><strong>CAUTION:</string> when using subclasses of this event handler, {@link #checkNoErrorOccurred()} MUST be called before attempting any action based on the imported data.
 * Doing otherwise will result in corrupted data.
 */
public abstract class AbstractRecordingTableImportEventHandler implements ITableImportEventHandler {
	
	private final ITableImportEventMessageFormatter formatter;
	
	private final TableImportNonFatalErrorHandling errorHandling;
	
	private boolean hasError = false;
	
	public AbstractRecordingTableImportEventHandler(ITableImportEventMessageFormatter formatter) {
		this(TableImportNonFatalErrorHandling.THROW_ON_CHECK, formatter);
	}
	
	public AbstractRecordingTableImportEventHandler(TableImportNonFatalErrorHandling errorHandling, ITableImportEventMessageFormatter formatter) {
		this.errorHandling = errorHandling;
		this.formatter = formatter;
	}

	protected abstract void record(ExcelImportErrorEvent event, TableImportLocation location, String formattedMessage);

	protected abstract void record(ExcelImportInfoEvent event, TableImportLocation location, String formattedMessage);

	@Override
	public void headerLabelMappingError(String expectedHeaderLabel, int indexAmongMatchedColumns, TableImportLocation location) throws TableImportHeaderLabelMappingException {
		this.hasError = true;
		String formattedMessage = formatter.formatHeaderLabelMappingErrorMessage(location, expectedHeaderLabel, indexAmongMatchedColumns);
		record(TableImportEvent.ERROR, location, formattedMessage);
		if (TableImportNonFatalErrorHandling.THROW_IMMEDIATELY.equals(errorHandling)) {
			throw new TableImportHeaderLabelMappingException(formattedMessage, expectedHeaderLabel, location);
		}
	}

	@Override
	public void checkNoMappingErrorOccurred() throws TableImportMappingException {
		if (hasError) {
			resetErrors();
			throw new TableImportMappingException("An error occurred; see the error report for more details");
		}
	}
	
	@Override
	public void event(ExcelImportErrorEvent event, TableImportLocation location, String message, Object ... args)
			throws TableImportContentException {
		this.hasError = true;
		String formattedMessage = formatter.formatErrorMessage(location, message, args);
		record(event, location, formattedMessage);
		
		if (event.isFatal() || TableImportNonFatalErrorHandling.THROW_IMMEDIATELY.equals(errorHandling)) {
			throw new TableImportContentException(formattedMessage);
		}
	}
	
	@Override
	public void event(ExcelImportInfoEvent event, TableImportLocation location, String message, Object ... args) {
		String formattedMessage = formatter.formatErrorMessage(location, message, args);
		record(event, location, formattedMessage);
	}
	

	@Override
	public void checkNoErrorOccurred() throws TableImportContentException {
		if (hasError) {
			resetErrors();
			throw new TableImportContentException("An error occurred; see the error report for more details");
		}
	}
	
	@Override
	public void resetErrors() {
		this.hasError = false;
	}

}