org.osgl.util.StringTokenSet Maven / Gradle / Ivy
The newest version!
package org.osgl.util;
/*-
* #%L
* Java Tool
* %%
* Copyright (C) 2014 - 2018 OSGL (Open Source General Library)
* %%
* 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 org.osgl.$;
import java.util.*;
/**
* `StringTokenSet` implement {@link Set} based on a list of String tokens separated by
* {@link #SEPARATOR}.
*
* Examples:
*
* * `"foo,bar"` contains `"foo"` and `"bar"`
* * `",,x,,y"` contains three empty string and `"x"`, `"y"`
*
* This data structure is better to be used in case the string token set are unlikely to
* change and the number of string tokens are not very big (no bigger than 20)
*
* This data structure is not thread safe
*/
public class StringTokenSet implements Set {
private String data;
private boolean sorted;
private int size;
private String[] array;
/**
* The default separator: `,`
*/
public static final String SEPARATOR = ",";
public static final char SEPARATOR_CHAR = ',';
public StringTokenSet() {
}
/**
* Construct a `StringTokenSet` with given string
* @param data the string contains tokens separated by {@link #SEPARATOR}
*/
public StringTokenSet(String data) {
StringTokenSet set = StringTokenSet.of(data);
$.copy(set).to(this);
}
@Override
public int size() {
return size;
}
@Override
public boolean isEmpty() {
return 0 == size;
}
@Override
public boolean contains(Object o) {
if (null == data || !String.class.isInstance(o)) {
return false;
}
int loc = locate((String) o);
return loc > -1;
}
@Override
public Iterator iterator() {
if (null == data) {
return Iterators.nil();
}
final List list = S.fastSplit(data, SEPARATOR);
return list.iterator();
}
@Override
public Object[] toArray() {
ensureArray();
return $.cloneOf(array);
}
@Override
public T[] toArray(T[] a) {
if (a.length < size) {
return $.cast(toArray());
}
ensureArray();
System.arraycopy(array, 0, a, 0, size);
return a;
}
@Override
public boolean add(String s) {
if (contains(s)) {
return false;
}
if (null == data) {
data = s;
} else {
data += SEPARATOR + s;
}
size++;
array = null;
sorted = false;
return true;
}
@Override
public boolean remove(Object o) {
if (null == data || !String.class.isInstance(o)) {
return false;
}
String s = (String) o;
int loc = locate(s);
if (loc < 0) {
return false;
}
if (1 == size) {
size = 0;
data = null;
} else {
int sz = s.length();
if (loc + sz >= data.length()) {
data = data.substring(0, loc - 1);
} else if (loc == 0) {
data = data.substring(sz + 1);
} else {
String prefix = data.substring(0, loc - 1);
String suffix = data.substring(loc + sz);
data = prefix + suffix;
}
size--;
}
array = null;
return true;
}
@Override
public boolean containsAll(Collection c) {
for (Object o : c) {
if (!contains(o)) {
return false;
}
}
return true;
}
@Override
public boolean addAll(Collection c) {
boolean changed = false;
Set set = C.Set(c);
for (String s : set) {
boolean b = add(s);
changed = changed || b;
}
return changed;
}
@Override
public boolean retainAll(Collection c) {
Set toBeRemoved = new HashSet<>();
for (String s: this) {
if (!c.contains(s)) {
toBeRemoved.add(s);
}
}
for (String s : toBeRemoved) {
remove(s);
}
return !toBeRemoved.isEmpty();
}
@Override
public boolean removeAll(Collection c) {
boolean changed = false;
for (Object o : c) {
boolean b = remove(o);
changed = changed || b;
}
return changed;
}
@Override
public void clear() {
data = null;
array = null;
size = 0;
}
@Override
public int hashCode() {
sort();
return $.hc(data);
}
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (obj instanceof StringTokenSet) {
StringTokenSet that = $.cast(obj);
if ($.eq(that.data, this.data)) {
return true;
}
sort();
that.sort();
return $.eq(data, that.data);
}
if (obj instanceof Set) {
Set set = (Set) obj;
return set.equals(this);
}
return false;
}
@Override
public String toString() {
return data;
}
public StringTokenSet sort() {
if (!sorted) {
ensureArray();
Arrays.sort(array);
data = S.join(C.listOf(array)).by(SEPARATOR).get();
sorted = true;
}
return this;
}
private int locate(String s) {
int sz = s.length();
int loc = data.indexOf(s);
while (loc != -1) {
boolean beginInTheMiddle = loc > 0 && data.charAt(loc - 1) != SEPARATOR_CHAR;
if (beginInTheMiddle) {
loc = data.indexOf(s, loc + 1);
continue;
}
int end = loc + sz;
boolean endInTheMiddle = size > end && data.charAt(end + 1) != SEPARATOR_CHAR;
if (endInTheMiddle) {
loc = data.indexOf(s, loc + 1);
continue;
}
return loc;
}
return -1;
}
private void ensureArray() {
if (null != array) {
return;
}
if (0 == size) {
array = S.EMPTY_ARRAY;
return;
}
array = new String[size];
int cur = 0;
int i = 0;
int loc = data.indexOf((int) SEPARATOR_CHAR, cur);
while (loc != -1) {
array[i++] = data.substring(cur, loc);
cur = loc + 1;
loc = data.indexOf((int) SEPARATOR_CHAR, cur);
}
array[i] = data.substring(cur, data.length());
}
public static StringTokenSet of(String data) {
StringTokenSet set = new StringTokenSet();
if (null != data) {
set.addAll(S.fastSplit(data, SEPARATOR));
}
return set;
}
public static String merge(String a, String b) {
if (null == a) {
if (null == b) {
return null;
}
return of(b).toString();
} else if (null == b) {
return of(a).toString();
}
String s = S.concat(a, SEPARATOR, b);
return of(s).toString();
}
public static String merge(String a, String ... others) {
return of(S.concat(a, S.join(others).by(SEPARATOR))).toString();
}
public static String merge(String[] sa) {
return of(S.join(sa).by(SEPARATOR).get()).toString();
}
public static String merge(Collection sa) {
return of(S.join(sa).by(SEPARATOR).get()).toString();
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy