org.hibernate.validator.internal.util.StringHelper Maven / Gradle / Ivy
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/*
* Hibernate Validator, declare and validate application constraints
*
* License: Apache License, Version 2.0
* See the license.txt file in the root directory or .
*/
package org.hibernate.validator.internal.util;
import java.lang.reflect.Field;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Arrays;
import java.util.Locale;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
/**
* Helper class dealing with strings.
*
* @author Gunnar Morling
*/
public class StringHelper {
private static final Pattern DOT = Pattern.compile( "\\." );
private StringHelper() {
}
/**
* Joins the elements of the given array to a string, separated by the given separator string.
*
* @param array the array to join
* @param separator the separator string
*
* @return a string made up of the string representations of the given array's members, separated by the given separator
* string
*/
public static String join(Object[] array, String separator) {
return array != null ? join( Arrays.asList( array ), separator ) : null;
}
/**
* Joins the elements of the given iterable to a string, separated by the given separator string.
*
* @param iterable the iterable to join
* @param separator the separator string
*
* @return a string made up of the string representations of the given iterable members, separated by the given separator
* string
*/
public static String join(Iterable iterable, String separator) {
if ( iterable == null ) {
return null;
}
StringBuilder sb = new StringBuilder();
boolean isFirst = true;
for ( Object object : iterable ) {
if ( !isFirst ) {
sb.append( separator );
}
else {
isFirst = false;
}
sb.append( object );
}
return sb.toString();
}
/**
* Returns the given string, with its first letter changed to lower-case unless the string starts with more than
* one upper-case letter, in which case the string will be returned unaltered.
*
* Provided to avoid a dependency on the {@link java.beans.Introspector} API which is not available on the Android
* platform (HV-779).
*
* @param string the string to decapitalize
*
* @return the given string, decapitalized. {@code null} is returned if {@code null} is passed as input; An empty
* string is returned if an empty string is passed as input
*
* @see java.beans.Introspector#decapitalize(String)
*/
public static String decapitalize(String string) {
if ( string == null || string.isEmpty() || startsWithSeveralUpperCaseLetters( string ) ) {
return string;
}
else {
return string.substring( 0, 1 ).toLowerCase( Locale.ROOT ) + string.substring( 1 );
}
}
/**
* Indicates if the string is null or is empty ie only contains whitespaces.
*
* @param value the string considered
* @return true if the string is null or only contains whitespaces
*/
public static boolean isNullOrEmptyString(String value) {
return value == null || value.trim().isEmpty();
}
/**
* Creates a compact string representation of the given member, useful for debugging or toString() methods. Package
* names are shortened, e.g. "org.hibernate.validator.internal.engine" becomes "o.h.v.i.e". Not to be used for
* user-visible log messages.
*/
public static String toShortString(Member member) {
if ( member instanceof Field ) {
return toShortString( (Field) member );
}
else if ( member instanceof Method ) {
return toShortString( (Method) member );
}
else {
return member.toString();
}
}
private static String toShortString(Field field) {
return toShortString( field.getGenericType() ) + " " + toShortString( field.getDeclaringClass() ) + "#" + field.getName();
}
private static String toShortString(Method method) {
return toShortString( method.getGenericReturnType() ) + " " +
method.getName() +
Arrays.stream( method.getGenericParameterTypes() )
.map( StringHelper::toShortString )
.collect( Collectors.joining( ", ", "(", ")" ) );
}
/**
* Creates a compact string representation of the given type, useful for debugging or toString() methods. Package
* names are shortened, e.g. "org.hibernate.validator.internal.engine" becomes "o.h.v.i.e". Not to be used for
* user-visible log messages.
*/
public static String toShortString(Type type) {
if ( type instanceof Class ) {
return toShortString( (Class) type );
}
else if ( type instanceof ParameterizedType ) {
return toShortString( (ParameterizedType) type );
}
else {
return type.toString();
}
}
private static String toShortString(Class type) {
if ( type.isArray() ) {
return toShortString( type.getComponentType() ) + "[]";
}
else if ( type.getEnclosingClass() != null ) {
return toShortString( type.getEnclosingClass() ) + "$" + type.getSimpleName();
}
else if ( type.getPackage() == null ) {
return type.getName();
}
return toShortString( type.getPackage() ) + "." + type.getSimpleName();
}
private static String toShortString(ParameterizedType parameterizedType) {
Class rawType = ReflectionHelper.getClassFromType( parameterizedType );
if ( rawType.getPackage() == null ) {
return parameterizedType.toString();
}
String typeArgumentsString = Arrays.stream( parameterizedType.getActualTypeArguments() )
.map( t -> toShortString( t ) )
.collect( Collectors.joining( ", ", "<", ">" ) );
return toShortString( rawType ) + typeArgumentsString;
}
private static String toShortString(Package pakkage) {
String[] packageParts = DOT.split( pakkage.getName() );
return Arrays.stream( packageParts )
.map( n -> n.substring( 0, 1 ) )
.collect( Collectors.joining( "." ) );
}
private static boolean startsWithSeveralUpperCaseLetters(String string) {
return string.length() > 1 &&
Character.isUpperCase( string.charAt( 0 ) ) &&
Character.isUpperCase( string.charAt( 1 ) );
}
}