package org.kuali.rice.core.api.mo.common;

 import java.util.Collection;

 import java.util.HashMap;

 import java.util.Map;

 import javax.xml.bind.annotation.XmlAccessType;

 import javax.xml.bind.annotation.XmlAccessorType;

 import javax.xml.bind.annotation.XmlAnyElement;

 import javax.xml.bind.annotation.XmlElement;

 import javax.xml.bind.annotation.XmlRootElement;

 import javax.xml.bind.annotation.XmlType;

 import org.apache.commons.lang.builder.CompareToBuilder;

 import org.apache.commons.lang.builder.EqualsBuilder;

 import org.apache.commons.lang.builder.HashCodeBuilder;

 import org.apache.commons.lang.builder.ToStringBuilder;

 import org.kuali.rice.core.api.CoreConstants;

 import org.kuali.rice.core.util.KeyValue;

 import org.w3c.dom.Element;

 /**

  * An immutable key value class. This class is has a comparison order

  * that string case-insensitive compares value then key.

  *

  * <p>

  * This class cannot be constructed with a null key but is allowed to have null values.

  * </p>

  */

 @XmlRootElement(name = ImmutableKeyValue.Constants.ROOT_ELEMENT_NAME)

 @XmlAccessorType(XmlAccessType.NONE)

 @XmlType(name = ImmutableKeyValue.Constants.TYPE_NAME, propOrder = {

         ImmutableKeyValue.Elements.KEY,

         ImmutableKeyValue.Elements.VALUE,

         CoreConstants.CommonElements.FUTURE_ELEMENTS

 })

 public class ImmutableKeyValue implements KeyValue, Comparable<KeyValue>{

     private static final long serialVersionUID = -4004980108397166233L;

         @XmlElement(name = Elements.KEY, required = true)

     private final String key;

     @XmlElement(name = Elements.VALUE, required = true)

     private final String value;

     @SuppressWarnings("unused")

     @XmlAnyElement

     private final Collection<Element> _futureElements = null;

     /**

      * This constructor should never be called except during JAXB unmarshalling.

      */

     private ImmutableKeyValue() {

         this.key = null;

         this.value = null;

     }

     private ImmutableKeyValue(String key, String value) {

         if (key == null) {

             throw new IllegalArgumentException("key is null");

         }

         this.key = key;

         this.value = value;

     }

     /**

      * Creates a ImmutableKeyValue from a {@link Map.Entry}.

      * @param entry cannot be null

      * @return key value

      * @throws IllegalArgumentException if the entry or the entry's key is null

      */

     public static ImmutableKeyValue fromMapEntry(Map.Entry<String, String> entry) {

         if (entry == null) {

             throw new IllegalArgumentException("entry is null");

         }

         return new ImmutableKeyValue(entry.getKey(), entry.getValue());

     }

     /**

      * Creates a ImmutableKeyValue from strings.

      * @param key cannot be null

      * @param value can be null

      * @return key value

      * @throws IllegalArgumentException if the key is null

      */

     public static ImmutableKeyValue fromStrings(String key, String value) {

         //key validation done in private ctor

         return new ImmutableKeyValue(key, value);

     }

     /**

      * Creates a ImmutableKeyValue from a {@link KeyValue}.

      * @param keyValue cannot be null

      * @return key value

      * @throws IllegalArgumentException if the keyValue or the keyValue's key is null

      */

     public static ImmutableKeyValue fromKeyValue(KeyValue keyValue) {

         if (keyValue == null) {

             throw new IllegalArgumentException("keyValue is null");

         }

         return new ImmutableKeyValue(keyValue.getKey(), keyValue.getValue());

     }

     /**

      * Converts key value to a mutable {@link Map} containing a single item.

      * The map returned is disconnected from this KeyValue class.

      *

      * @return a Map

      */

     public Map<String, String> toMap() {

         Map<String, String> m = new HashMap<String, String>();

         m.put(key, value);

         return m;

     }

     /**

      * Converts key value to a mutable {@link Map.Entry}.

      * The entry returned is disconnected from this KeyValue class.

      *

      * @return an entry

      */

     public Map.Entry<String, String> toMapEntry() {

         return new HashMap.SimpleEntry<String, String>(key, value);

     }

     @Override

     public String getKey() {

         return key;

     }

     @Override

     public String getValue() {

         return value;

     }

     @Override

         public int compareTo(KeyValue o) {

                 if (o == null) {

                         throw new NullPointerException("o is null");

                 }

                 return new CompareToBuilder()

                         .append(this.getValue(), o.getValue(), String.CASE_INSENSITIVE_ORDER)

                         .append(this.getKey(), o.getKey(), String.CASE_INSENSITIVE_ORDER)

                         .toComparison();

         }

     @Override

     public int hashCode() {

         return HashCodeBuilder.reflectionHashCode(this, Constants.HASH_CODE_EQUALS_EXCLUDE);

     }

     @Override

     public boolean equals(Object obj) {

         return EqualsBuilder.reflectionEquals(obj, this, Constants.HASH_CODE_EQUALS_EXCLUDE);

     }

     @Override

     public String toString() {

         return ToStringBuilder.reflectionToString(this);

     }

     /**

      * Defines some internal constants used on this class.

      */

     static class Constants {

         final static String ROOT_ELEMENT_NAME = "keyValue";

         final static String TYPE_NAME = "KeyValueType";

         final static String[] HASH_CODE_EQUALS_EXCLUDE = {CoreConstants.CommonElements.FUTURE_ELEMENTS};

     }

     /**

      * A private class which exposes constants which define the XML element names to use

      * when this object is marshalled to XML.

      */

     static class Elements {

         final static String KEY = "key";

         final static String VALUE = "value";

     }

 }