/**

  * Copyright (c) 2008-2011, http://www.snakeyaml.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.yaml.snakeyaml.nodes;

 import java.math.BigDecimal;

 import java.math.BigInteger;

 import java.net.URI;

 import java.sql.Timestamp;

 import java.util.Date;

 import java.util.HashMap;

 import java.util.HashSet;

 import java.util.Map;

 import java.util.Set;

 import org.yaml.snakeyaml.error.YAMLException;

 import org.yaml.snakeyaml.util.UriEncoder;

 public final class Tag implements Comparable<Tag> {

     public static final String PREFIX = "tag:yaml.org,2002:";

     public static final Tag YAML = new Tag(PREFIX + "yaml");

     public static final Tag VALUE = new Tag(PREFIX + "value");

     public static final Tag MERGE = new Tag(PREFIX + "merge");

     public static final Tag SET = new Tag(PREFIX + "set");

     public static final Tag PAIRS = new Tag(PREFIX + "pairs");

     public static final Tag OMAP = new Tag(PREFIX + "omap");

     public static final Tag BINARY = new Tag(PREFIX + "binary");

     public static final Tag INT = new Tag(PREFIX + "int");

     public static final Tag FLOAT = new Tag(PREFIX + "float");

     public static final Tag TIMESTAMP = new Tag(PREFIX + "timestamp");

     public static final Tag BOOL = new Tag(PREFIX + "bool");

     public static final Tag NULL = new Tag(PREFIX + "null");

     public static final Tag STR = new Tag(PREFIX + "str");

     public static final Tag SEQ = new Tag(PREFIX + "seq");

     public static final Tag MAP = new Tag(PREFIX + "map");

     public static final Map<Tag, Set<Class<?>>> COMPATIBILITY_MAP;

     static {

         COMPATIBILITY_MAP = new HashMap<Tag, Set<Class<?>>>();

         Set<Class<?>> floatSet = new HashSet<Class<?>>();

         floatSet.add(Double.class);

         floatSet.add(Float.class);

         floatSet.add(BigDecimal.class);

         COMPATIBILITY_MAP.put(FLOAT, floatSet);

         //

         Set<Class<?>> intSet = new HashSet<Class<?>>();

         intSet.add(Integer.class);

         intSet.add(Long.class);

         intSet.add(BigInteger.class);

         COMPATIBILITY_MAP.put(INT, intSet);

         //

         Set<Class<?>> timestampSet = new HashSet<Class<?>>();

         timestampSet.add(Date.class);

         timestampSet.add(java.sql.Date.class);

         timestampSet.add(Timestamp.class);

         COMPATIBILITY_MAP.put(TIMESTAMP, timestampSet);

     }

     private final String value;

     public Tag(String tag) {

         if (tag == null) {

             throw new NullPointerException("Tag must be provided.");

         } else if (tag.length() == 0) {

             throw new IllegalArgumentException("Tag must not be empty.");

         } else if (tag.trim().length() != tag.length()) {

             throw new IllegalArgumentException("Tag must not contain leading or trailing spaces.");

         }

         this.value = UriEncoder.encode(tag);

     }

     public Tag(Class<? extends Object> clazz) {

         if (clazz == null) {

             throw new NullPointerException("Class for tag must be provided.");

         }

         this.value = Tag.PREFIX + UriEncoder.encode(clazz.getName());

     }

     public Tag(URI uri) {

         if (uri == null) {

             throw new NullPointerException("URI for tag must be provided.");

         }

         this.value = uri.toASCIIString();

     }

     public String getValue() {

         return value;

     }

     public boolean startsWith(String prefix) {

         return value.startsWith(prefix);

     }

     public String getClassName() {

         if (!value.startsWith(Tag.PREFIX)) {

             throw new YAMLException("Invalid tag: " + value);

         }

         return UriEncoder.decode(value.substring(Tag.PREFIX.length()));

     }

     public int getLength() {

         return value.length();

     }

     @Override

     public String toString() {

         return value;

     }

     @Override

     public boolean equals(Object obj) {

         if (obj == null) {

             return false;

         }

         if (obj instanceof Tag) {

             return value.equals(((Tag) obj).getValue());

         } else if (obj instanceof String) {

             if (value.equals(obj.toString())) {

                 // TODO to be removed later (version 2.0?)

                 System.err.println("Comparing Tag and String is deprecated.");

                 return true;

             }

         }

         return false;

     }

     @Override

     public int hashCode() {

         return value.hashCode();

     }

     /**

      * Java has more then 1 class compatible with a language-independent tag

      * (!!int, !!float, !!timestamp etc)

      * 

      * @param clazz

      *            - Class to check compatibility

      * @return true when the Class can be represented by this

      *         language-independent tag

      */

     public boolean isCompatible(Class<?> clazz) {

         Set<Class<?>> set = COMPATIBILITY_MAP.get(this);

         if (set != null) {

             return set.contains(clazz);

         } else {

             return false;

         }

     }

     /**

      * Check whether this tag matches the global tag for the Class

      * 

      * @param clazz

      *            - Class to check

      * @return true when the this tag can be used as a global tag for the Class

      */

     public boolean matches(Class<? extends Object> clazz) {

         return value.equals(Tag.PREFIX + clazz.getName());

     }

     public int compareTo(Tag o) {

         return value.compareTo(o.getValue());

     }

 }