001/*******************************************************************************
002 * Copyright (c) 2015 EclipseSource.
003 *
004 * Permission is hereby granted, free of charge, to any person obtaining a copy
005 * of this software and associated documentation files (the "Software"), to deal
006 * in the Software without restriction, including without limitation the rights
007 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
008 * copies of the Software, and to permit persons to whom the Software is
009 * furnished to do so, subject to the following conditions:
010 *
011 * The above copyright notice and this permission notice shall be included in all
012 * copies or substantial portions of the Software.
013 *
014 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
015 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
016 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
017 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
018 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
019 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
020 * SOFTWARE.
021 ******************************************************************************/
022package com.restfb.json;
023
024import java.io.IOException;
025import java.io.Writer;
026import java.util.Arrays;
027import java.util.stream.Collectors;
028import java.util.stream.Stream;
029
030/**
031 * Enables human readable JSON output by inserting whitespace between values.after commas and colons. Example:
032 *
033 * <pre>
034 * jsonValue.writeTo(writer, PrettyPrint.singleLine());
035 * </pre>
036 */
037public class PrettyPrint implements WriterConfig {
038
039  private final char[] indentChars;
040
041  protected PrettyPrint(char[] indentChars) {
042    this.indentChars = indentChars;
043  }
044
045  /**
046   * Print every value on a separate line. Use tabs (<code>\t</code>) for indentation.
047   *
048   * @return A PrettyPrint instance for wrapped mode with tab indentation
049   */
050  public static PrettyPrint singleLine() {
051    return new PrettyPrint(null);
052  }
053
054  /**
055   * Print every value on a separate line. Use the given number of spaces for indentation.
056   *
057   * @param number
058   *          the number of spaces to use
059   * @return A PrettyPrint instance for wrapped mode with spaces indentation
060   */
061  public static PrettyPrint indentWithSpaces(int number) {
062    if (number < 0) {
063      throw new IllegalArgumentException("number is negative");
064    }
065    char[] chars = new char[number];
066    Arrays.fill(chars, ' ');
067    return new PrettyPrint(chars);
068  }
069
070  /**
071   * Do not break lines, but still insert whitespace between values.
072   *
073   * @return A PrettyPrint instance for single-line mode
074   */
075  public static PrettyPrint indentWithTabs() {
076    return new PrettyPrint(new char[] { '\t' });
077  }
078
079  @Override
080  public JsonWriter createWriter(Writer writer) {
081    return new PrettyPrintWriter(writer, indentChars);
082  }
083
084  private static class PrettyPrintWriter extends JsonWriter {
085
086    private final char[] indentChars;
087    private int indent;
088
089    private PrettyPrintWriter(Writer writer, char[] indentChars) {
090      super(writer);
091      this.indentChars = indentChars;
092    }
093
094    @Override
095    protected void writeArrayOpen() throws IOException {
096      indent++;
097      writer.write('[');
098      writeNewLine();
099    }
100
101    @Override
102    protected void writeArrayClose() throws IOException {
103      indent--;
104      writeNewLine();
105      writer.write(']');
106    }
107
108    @Override
109    protected void writeArraySeparator() throws IOException {
110      writeCommaSeparator();
111    }
112
113    @Override
114    protected void writeObjectOpen() throws IOException {
115      indent++;
116      writer.write('{');
117      writeNewLine();
118    }
119
120    @Override
121    protected void writeObjectClose() throws IOException {
122      indent--;
123      writeNewLine();
124      writer.write('}');
125    }
126
127    @Override
128    protected void writeMemberSeparator() throws IOException {
129      writer.write(':');
130      writer.write(' ');
131    }
132
133    @Override
134    protected void writeObjectSeparator() throws IOException {
135      writeCommaSeparator();
136    }
137
138    protected void writeCommaSeparator() throws IOException {
139      writer.write(',');
140      if (!writeNewLine()) {
141        writer.write(' ');
142      }
143    }
144
145    private boolean writeNewLine() throws IOException {
146      if (indentChars == null) {
147        return false;
148      }
149      writer.write('\n');
150      writer.write(Stream.generate(() -> String.valueOf(indentChars)).limit(indent).collect(Collectors.joining()));
151      return true;
152    }
153
154  }
155
156}