001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
005// * with the License.  You may obtain a copy of the License at                                                              *
006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
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010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.transforms;
014
015import static org.apache.juneau.internal.IOUtils.*;
016
017import java.io.*;
018
019import org.apache.juneau.*;
020import org.apache.juneau.html.*;
021import org.apache.juneau.json.*;
022import org.apache.juneau.parser.*;
023import org.apache.juneau.transform.*;
024import org.apache.juneau.uon.*;
025import org.apache.juneau.urlencoding.*;
026import org.apache.juneau.xml.*;
027
028/**
029 * Transforms the contents of a {@link Reader} into an {@code Object}.
030 *
031 * <h5 class='topic'>Description</h5>
032 *
033 * The {@code Reader} must contain JSON, Juneau-generated XML (output from {@link XmlSerializer}), or Juneau-generated
034 * HTML (output from {@link JsonSerializer}) in order to be parsed correctly.
035 *
036 * <p>
037 * Useful for serializing models that contain {@code Readers} created by {@code RestCall} instances.
038 *
039 * <p>
040 * This is a one-way transform, since {@code Readers} cannot be reconstituted.
041 *
042 * <h5 class='topic'>Behavior-specific subclasses</h5>
043 *
044 * The following direct subclasses are provided for convenience:
045 * <ul>
046 *    <li>{@link Json} - Parses JSON text.
047 *    <li>{@link Xml} - Parses XML text.
048 *    <li>{@link Html} - Parses HTML text.
049 *    <li>{@link PlainText} - Parses plain text.
050 * </ul>
051 */
052public class ReaderSwap extends PojoSwap<Reader,Object> {
053
054   /** Reader transform for reading JSON text. */
055   public static class Json extends ReaderSwap {
056      /** Constructor */
057      public Json() {
058         super(JsonParser.DEFAULT);
059      }
060   }
061
062   /** Reader transform for reading XML text. */
063   public static class Xml extends ReaderSwap {
064      /** Constructor */
065      public Xml() {
066         super(XmlParser.DEFAULT);
067      }
068   }
069
070   /** Reader transform for reading HTML text. */
071   public static class Html extends ReaderSwap {
072      /** Constructor */
073      public Html() {
074         super(HtmlParser.DEFAULT);
075      }
076   }
077
078   /** Reader transform for reading plain text. */
079   public static class PlainText extends ReaderSwap {
080      /** Constructor */
081      public PlainText() {
082         super(null);
083      }
084   }
085
086   /** Reader transform for reading plain text. */
087   public static class Uon extends ReaderSwap {
088      /** Constructor */
089      public Uon() {
090         super(UonParser.DEFAULT);
091      }
092   }
093
094   /** Reader transform for reading plain text. */
095   public static class UrlEncoding extends ReaderSwap {
096      /** Constructor */
097      public UrlEncoding() {
098         super(UrlEncodingParser.DEFAULT);
099      }
100   }
101
102   /** The parser to use to parse the contents of the Reader. */
103   private ReaderParser parser;
104
105   /**
106    * @param parser The parser to use to convert the contents of the reader to Java objects.
107    */
108   public ReaderSwap(ReaderParser parser) {
109      this.parser = parser;
110   }
111
112   /**
113    * Converts the specified {@link Reader} to an {@link Object} whose type is determined by the contents of the reader.
114    */
115   @Override /* PojoSwap */
116   public Object swap(BeanSession session, Reader o) throws Exception {
117      if (parser == null)
118         return read(o);
119      return parser.parse(o, Object.class);
120   }
121}