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Charba, GWT Chart library based on CHART.JS
/**
Copyright 2017 Andrea "Stock" Stocchero
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.pepstock.charba.client.commons;
/**
* Represents the property key of a JavaScript object.
* Used for enum.
*
* @author Andrea "Stock" Stocchero
*/
public interface Key {
/**
* Returns a key instance by its string value.
*
* @param key string value to use
* @return a standard key instance
*/
static Key create(String key) {
return new StandardKey(key);
}
/**
* Returns true if key passed as argument is not null and its value is not null as well.
*
* @param key key to be checked
* @return true if key passed as argument is not null and its value is not null as well.
*/
static boolean isValid(Key key) {
return key != null && key.value() != null && key.value().trim().length() > 0;
}
/**
* Checks if key passed as argument is not null and its value is not null as well.
* If not, throw a {@link IllegalArgumentException}.
*
* @param key key to be checked
*/
static void checkIfValid(Key key) {
if (!isValid(key)) {
throw new IllegalArgumentException("Key is null or not consistent");
}
}
/**
* Checks if key passed as argument is not null and its value is not null as well.
* If not, throw a {@link IllegalArgumentException}, otherwise it returns the key.
*
* @param key key to be checked
* @param type of key
* @return the same key passed as argument
*/
static T checkAndGetIfValid(T key) {
// checks if key is consistent
checkIfValid(key);
// if here, is consistent
// then returns the argument
return key;
}
/**
* Returns true if a key in the an enumeration is related to the value, otherwise false.
*
* @param enumValues enumeration values of keys
* @param value value to search in the key
* @param type of key
* @return true if a key in the an enumeration is related to the value, otherwise false
*/
static boolean hasKeyByValue(T[] enumValues, String value) {
return getKeyByValue(enumValues, value, null) != null;
}
/**
* Returns a key in the an enumeration by the value.
*
* @param enumValues enumeration values of keys
* @param value value to search in the key
* @param type of key
* @return the found key by value or null
*/
static T getKeyByValue(T[] enumValues, String value) {
return getKeyByValue(enumValues, value, null);
}
/**
* Returns a key in the an enumeration by the value, or the default key passed as argument.
*
* @param enumValues enumeration values of keys
* @param value value to search in the key
* @param defaultKey default key instance if the value is not found
* @param type of key
* @return the found key by value or the default one
*/
static T getKeyByValue(T[] enumValues, String value, T defaultKey) {
// checks if arguments are consistent
if (value != null && enumValues != null && enumValues.length > 0) {
// scans enumeration
for (T enumValue : enumValues) {
// checks if enumeration value name is equals to value
if (enumValue.value().equalsIgnoreCase(value)) {
// returns EnumValue
return enumValue;
}
}
}
// if here the arguments are not consistent or the
// value has not found
// then returns default
return defaultKey;
}
/**
* Compares the two specified key values.
*
* @param k1 the first key to compare
* @param k2 the second key to compare
* @return the value 0 if k1 value is equal to k2; a value less than 0 if k1 value is less than k2; and a value greater than 0 if k1 value is greater than k2.
*/
static int compare(Key k1, Key k2) {
// checks if k1 argument is consistent
if (!Key.isValid(k1)) {
// checks if k2 argument is consistent
if (!Key.isValid(k2)) {
// both are null then equals
return 0;
}
// k2 is greater being not null
return -1;
} else {
// checks if k2 argument is consistent
if (!Key.isValid(k2)) {
// k2 is less being not null
return 1;
}
// compares values
return k1.value().compareToIgnoreCase(k2.value());
}
}
/**
* Returns true if the keys have got the same value.
*
* @param k1 the first key to compare
* @param k2 the second key to compare
* @return true if the keys have got the same value
*/
static boolean equals(Key k1, Key k2) {
return compare(k1, k2) == 0;
}
/**
* Returns the name value of property
*
* @return the name value of property
*/
String value();
}