org.ff4j.utils.Util Maven / Gradle / Ivy
package org.ff4j.utils;
import java.lang.reflect.Constructor;
/*
* #%L
* ff4j-core
* %%
* Copyright (C) 2013 - 2014 Ff4J
* %%
* 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.
* #L%
*/
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
/**
* Tips and tricks to be less verbose.
*
* @author Cedrick Lunven (@clunven)
*/
public class Util {
/** Start Color. */
private static final String START_COLOR = "00AB8B";
/** End Color. */
private static final String END_COLOR = "EEFFEE";
private Util() {
}
/**
* Check that expression is true.
*
* @param expression
* expression to evaluate
*/
public static boolean hasLength(String expression) {
return expression != null && !"".equals(expression);
}
/**
* Check that expression is true.
*
* @param expression
* expression to evaluate
*/
public static void assertTrue(boolean expression) {
if (!expression) {
throw new IllegalArgumentException("[Assertion failed] - this expression must be true");
}
}
/**
* Check that object is null.
*
* @param object
* target object
*/
public static void assertNull(Object object) {
if (object != null) {
throw new IllegalArgumentException("[Assertion failed] - the object argument must be null");
}
}
/**
* Check that object is not null.
*
* @param object
* target object
*/
public static void assertNotNull(Object... params) {
assertNotNull("parameter", params);
}
/**
* Check that object is not null.
*
* @param object
* target object
*/
public static void assertNotNull(String objectName, Object... params) {
if (params != null) {
for (int idx = 0; idx < params.length ;idx++) {
Object currentparam = params[idx];
if (null == currentparam) {
throw new IllegalArgumentException("[Assertion failed] - " + objectName + " must not be null");
}
}
}
}
/**
* Check that string is not null
*
* @param object
* target object
*/
public static void assertHasLength(String... params) {
if (params != null) {
for (int idx = 0; idx < params.length ;idx++) {
String currentparam = params[idx];
if (null == currentparam || currentparam.isEmpty()) {
throw new IllegalArgumentException("[Assertion failed] - Parameter #" + idx + "(string) must not be null nor empty");
}
}
}
}
/**
* Check that string is not null
*
* @param object
* target object
*/
public static void assertNotEmpty(Collection collec) {
if (null == collec || collec.isEmpty()) {
throw new IllegalArgumentException("[Assertion failed] - Target COLLECTION must not be null nor empty");
}
}
/**
* Parameter validation.
*
* @param param
* current parameter
* @param paramName
* current parameter name
*/
public static void assertParamHasLength(String param, String paramName) {
if (param == null || param.isEmpty()) {
throw new IllegalArgumentException("Missing Parameter '" + paramName + "' must not be null nor empty");
}
}
/**
* Create an HashSet.
*
* @param els
* enumeration of elements
* @return
*/
public static Set set(T... els) {
return new HashSet(Arrays.asList(els));
}
/**
* Create an HashSet.
*
* @param els
* enumeration of elements
* @return
*/
public static List list(T... els) {
return new ArrayList(Arrays.asList(els));
}
/**
* This code build the color gradient between 2 colors with defined step.
* @param codeFrom
* color source
* @param codeTo
* color destination
* @param nbDivision
* number of steps
* @return
* the list of colors
*/
private static List < String > getColorGradient(String codeFrom, String codeTo, int nbDivision) {
List < String > colors = new ArrayList();
if (nbDivision > 0) {
int rStart = Integer.parseInt(codeFrom.substring(0, 2), 16);
int rDelta = (Integer.parseInt(codeTo.substring(0, 2), 16) - rStart) / nbDivision;
int gStart = Integer.parseInt(codeFrom.substring(2, 4), 16);
int gDelta = (Integer.parseInt(codeTo.substring(2, 4), 16) - gStart) / nbDivision;
int bStart = Integer.parseInt(codeFrom.substring(4, 6), 16);
int bDelta = (Integer.parseInt(codeTo.substring(4, 6), 16) - bStart) / nbDivision;
for (int idx = 0;idx < nbDivision;idx++) {
String red = Integer.toHexString(rStart + rDelta * idx);
String green = Integer.toHexString(gStart + gDelta * idx);
String blue = Integer.toHexString(bStart + bDelta * idx);
colors.add(red + green + blue);
}
}
return colors;
}
/**
* Dedicated gradient for ff4j console (Pie Chart).
*
* @param nbsectors
* target sectors
* @return
* color gradient
*/
public static List < String > getColorsGradient(int nbsectors) {
return getColorGradient(START_COLOR, END_COLOR, nbsectors);
}
/**
* Allow to instanciate utility class.
*
* @param utilityClass
* current utility
* @return
* instance
* @throws Exception
*/
public static T instanciatePrivate(Class utilityClass) throws Exception {
Constructor ce = utilityClass.getDeclaredConstructor();
ce.setAccessible(true);
return ce.newInstance();
}
/**
* Get key listfrom value.
*
* @param map
* current MAP
* @param value
* value of MAP
* @return
*/
public static Set getKeysByValue(Map map, E value) {
if (map == null) return null;
Set keys = new HashSet();
for (Entry entry : map.entrySet()) {
if (value != null && value.equals(entry.getValue())) {
keys.add(entry.getKey());
}
}
return keys;
}
/**
* Get a first key matching from value.
*
* @param map
* current MAP
* @param value
* value of MAP
* @return
*/
public static T getFirstKeyByValue(Map map, E value) {
if (map == null) return null;
for (Entry entry : map.entrySet()) {
if (value != null && value.equals(entry.getValue())) {
return entry.getKey();
}
}
return null;
}
}
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