PrettyJsonWriter.java

/*
 * ModeShape (http://www.modeshape.org)
 *
 * 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.modeshape.schematic.internal.document;

import java.io.IOException;
import java.io.Writer;
import java.lang.reflect.Array;
import java.util.Iterator;
import org.modeshape.schematic.document.Document;
import org.modeshape.schematic.document.Document.Field;

public class PrettyJsonWriter extends CompactJsonWriter {

   private static final int MAX_CACHED_INDENTS = 10;
   private static final String[] CACHED_INDENTS;

   static {
      CACHED_INDENTS = new String[MAX_CACHED_INDENTS];
      CACHED_INDENTS[0] = "";
      StringBuilder sb = new StringBuilder();
      for (int i = 1; i != MAX_CACHED_INDENTS; ++i) {
         sb.append(' ').append(' ');
         CACHED_INDENTS[i] = sb.toString();
      }
   }

   private int depth = 0;

   @Override
   protected void write(Document bson, Writer writer) throws IOException {
      if (bson.size() == 0) {
         writer.append("{ }");
         return;
      }
      ++depth;
      writer.append('{').append('\n');
      indent(writer);
      Iterator<Field> iter = bson.fields().iterator();
      if (iter.hasNext()) {
         write(iter.next(), writer);
         while (iter.hasNext()) {
            writer.append(',').append('\n');
            indent(writer);
            write(iter.next(), writer);
         }
      }
      writer.append('\n');
      --depth;
      indent(writer);
      writer.append('}');
   }

   @Override
   protected void write(Iterable<?> arrayValue, Writer writer) throws IOException {
      ++depth;
      writer.append('[');
      boolean first = true;
      for (Object value : arrayValue) {
         if (first) {
            first = false;
            writer.append('\n');
            indent(writer);
         } else {
            writer.append(',').append('\n');
            indent(writer);
         }
         write(value, writer);
      }
      --depth;
      if (first) {
         writer.append(' ');
      } else {
         writer.append('\n');
         indent(writer);
      }
      writer.append(']');
   }

   @Override
   protected void writeArray(Object array, Writer writer) throws IOException {
      final int len = Array.getLength(array);
      if (len == 0) {
         writer.append("[ ]");
         return;
      }
      ++depth;
      writer.append('[').append('\n');
      indent(writer);
      for (int i = 0; i < len; i++) {
         if (i > 0) {
            writer.append(',').append('\n');
            indent(writer);
         }
         write(Array.get(array, i), writer);
      }
      writer.append('\n');
      --depth;
      indent(writer);
      writer.append(']');
   }

   protected void indent(Writer writer) throws IOException {
      if (depth == 0) {
         return;
      }
      if (depth < MAX_CACHED_INDENTS) {
         writer.append(CACHED_INDENTS[depth]);
      } else {
         for (int i = 0; i != depth; ++i) {
            writer.append(' ').append(' ');
         }
      }
   }
}