JSONSimpleExporter.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 ro.nextreports.engine.exporter;

import java.io.PrintStream;
import java.io.UnsupportedEncodingException;
import java.util.HashSet;
import java.util.Set;

import ro.nextreports.engine.Report;
import ro.nextreports.engine.band.Band;
import ro.nextreports.engine.band.BandElement;
import ro.nextreports.engine.band.Hyperlink;
import ro.nextreports.engine.band.HyperlinkBandElement;
import ro.nextreports.engine.band.ReportBandElement;
import ro.nextreports.engine.exporter.CellElement;
import ro.nextreports.engine.exporter.ExporterBean;
import ro.nextreports.engine.exporter.ResultExporter;
import ro.nextreports.engine.queryexec.QueryException;
import ro.nextreports.engine.util.StringUtil;

/**
 * @author daniel.avieritei
 */
public class JSONSimpleExporter extends ResultExporter {

	private PrintStream stream;

	private char separator = ',';

	/**
	 * quote character, usually '\"' '\'' for SOL used to enclose fields
	 * containing a separator character.
	 */
	private char quote = '\"';

	/**
	 * line separator to use. We use Windows style for all platforms since csv
	 * is a Windows format file.
	 */
	private static final String lineSeparator = "]} \r\n";

	/**
	 * true if there has was a field previously written to this line, meaning
	 * there is a comma pending to be written.
	 */
	private boolean wasPreviousField = false;

	/**
	 * how much extra quoting you want
	 */
	private int quoteLevel = 1;

	/**
	 * true if write should trim lead/trail whitespace from fields before
	 * writing them.
	 */
	private final boolean trim = true;
	private boolean isFirstRow;

	public JSONSimpleExporter(ExporterBean bean) {
		super(bean);
	}

	public JSONSimpleExporter(ExporterBean bean, char delimiter) {
		super(bean);
		separator = delimiter;
	}

	protected void initExport() throws QueryException {
		stream = createPrintStream();
		stream.print("{" + quote + "rows" + quote + " : [");
		isFirstRow = true;
	}

	protected void finishExport() {
		stream.print("]}");
		stream.flush();
		if (!bean.isSubreport()) {
			stream.close();
		}
	}

	protected void close() {
		if (!bean.isSubreport()) {
			stream.close();
		}
	}

	protected void flush() {
		if (resultSetRow % FLUSH_ROWS == 0) {
			flushNow();
		}
	}

	protected void flushNow() {
		stream.flush();
	}

	protected Set<CellElement> getIgnoredCells(Band band) {
		return new HashSet<CellElement>();
	}

	protected void exportCell(String bandName, BandElement bandElement, Object value, int gridRow, int row, int column,
			int cols, int rowSpan, int colSpan, boolean isImage) {
		if (bandElement instanceof HyperlinkBandElement) {
			Hyperlink hyperlink = ((HyperlinkBandElement) bandElement).getHyperlink();
			value = hyperlink.getText();
		} else if (bandElement instanceof ReportBandElement) {
			Report report = ((ReportBandElement) bandElement).getReport();
			ExporterBean eb = null;
			try {
				eb = getSubreportExporterBean(report);
				JSONSimpleExporter subExporter = new JSONSimpleExporter(eb);
				subExporter.export();
				value = subExporter.getSubreportData();
			} catch (Exception e) {
				e.printStackTrace();
			} finally {
				if ((eb != null) && (eb.getResult() != null)) {
					eb.getResult().close();
				}
			}
		}
		put(stream, StringUtil.getValueAsString(value, getPattern(bandElement), getReportLanguage()));
		if (column == cols - 1) {
			nl(stream);
		}
	}

	protected void afterRowExport() {
	}

	protected String getNullElement() {
		return null;
	}

	/**
	 * Write one csv field to the file, followed by a separator unless it is the
	 * last field on the line. Lead and trailing blanks will be removed.
	 *
	 * @param p
	 *            print stream
	 * @param s
	 *            The string to write. Any additional quotes or embedded quotes
	 *            will be provided by put. Null means start a new line.
	 */
	private void put(PrintStream p, String s) {
		if (s == null) {
			// nl();
			put(p, " ");
			return;
		}

		if (wasPreviousField) {
			p.print(separator);
		} else {
			// first character
			//do not put at first row?
			if (isFirstRow){
				p.print("{\"row\": [");
				isFirstRow = false;
			} else {
				p.print(",{\"row\": [");
			}
		}
		if (trim) {
			s = s.trim();
		}

		if (s.indexOf(quote) >= 0) {
			/*
			 * worst case, needs surrounding quotes and internal quotes doubled
			 */
			p.print(quote);
			for (int i = 0; i < s.length(); i++) {
				char c = s.charAt(i);
				if (c == quote) {
					p.print(quote);
					p.print(quote);
				} else {
					p.print(c);
				}
			}
			p.print(quote);
		} else if (quoteLevel == 2 || quoteLevel == 1 && s.indexOf(' ') >= 0 || s.indexOf(separator) >= 0) {
			/* need surrounding quotes */
			p.print(quote);
			p.print(s);
			p.print(quote);
		} else {
			/* ordinary case, no surrounding quotes needed */
			p.print(quote);
			p.print(s);
			p.print(quote);
		}
		/* make a note to print trailing comma later */
		wasPreviousField = true;
	}

	/**
	 * Write a new line in the CVS output file to demark the end of record.
	 *
	 * @param p
	 *            print stream
	 */
	public void nl(PrintStream p) {
		/* don't bother to write last pending comma on the line */
		p.print(lineSeparator);
		wasPreviousField = false;
	}

	private String getSubreportData() {
		try {
			return subreportStream.toString("UTF-8");
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
			return "";
		} finally {
			stream.close();
		}
	}
	public PrintStream getStream() {
		return stream;
	}
}