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Posted to commits@commons.apache.org by gg...@apache.org on 2018/05/22 14:41:00 UTC
[lang] [LANG-1290] StringUtils.join() with support for List with
configurable start/end indices.
Repository: commons-lang
Updated Branches:
refs/heads/master 09ef69c5b -> 87937b2e7
[LANG-1290] StringUtils.join() with support for List<?> with
configurable start/end indices.
Project: http://git-wip-us.apache.org/repos/asf/commons-lang/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-lang/commit/87937b2e
Tree: http://git-wip-us.apache.org/repos/asf/commons-lang/tree/87937b2e
Diff: http://git-wip-us.apache.org/repos/asf/commons-lang/diff/87937b2e
Branch: refs/heads/master
Commit: 87937b2e7192524306aa58d74c90537eec997cfa
Parents: 09ef69c
Author: Jochen Schalanda <jo...@schalanda.name>
Authored: Tue May 22 08:40:55 2018 -0600
Committer: Gary Gregory <ga...@gmail.com>
Committed: Tue May 22 08:40:55 2018 -0600
----------------------------------------------------------------------
.../org/apache/commons/lang3/StringUtils.java | 76 ++++++++++++++++++++
.../apache/commons/lang3/StringUtilsTest.java | 38 ++++++++++
2 files changed, 114 insertions(+)
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http://git-wip-us.apache.org/repos/asf/commons-lang/blob/87937b2e/src/main/java/org/apache/commons/lang3/StringUtils.java
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diff --git a/src/main/java/org/apache/commons/lang3/StringUtils.java b/src/main/java/org/apache/commons/lang3/StringUtils.java
index 495e4ec..9387376 100644
--- a/src/main/java/org/apache/commons/lang3/StringUtils.java
+++ b/src/main/java/org/apache/commons/lang3/StringUtils.java
@@ -4722,6 +4722,82 @@ public class StringUtils {
}
/**
+ * <p>Joins the elements of the provided {@code List} into a single String
+ * containing the provided list of elements.</p>
+ *
+ * <p>No delimiter is added before or after the list.
+ * Null objects or empty strings within the array are represented by
+ * empty strings.</p>
+ *
+ * <pre>
+ * StringUtils.join(null, *) = null
+ * StringUtils.join([], *) = ""
+ * StringUtils.join([null], *) = ""
+ * StringUtils.join(["a", "b", "c"], ';') = "a;b;c"
+ * StringUtils.join(["a", "b", "c"], null) = "abc"
+ * StringUtils.join([null, "", "a"], ';') = ";;a"
+ * </pre>
+ *
+ * @param list the {@code List} of values to join together, may be null
+ * @param separator the separator character to use
+ * @param startIndex the first index to start joining from. It is
+ * an error to pass in an end index past the end of the list
+ * @param endIndex the index to stop joining from (exclusive). It is
+ * an error to pass in an end index past the end of the list
+ * @return the joined String, {@code null} if null list input
+ * @since 3.8
+ */
+ public static String join(final List<?> list, final char separator, final int startIndex, final int endIndex) {
+ if (list == null) {
+ return null;
+ }
+ final int noOfItems = endIndex - startIndex;
+ if (noOfItems <= 0) {
+ return EMPTY;
+ }
+ final List<?> subList = list.subList(startIndex, endIndex);
+ return join(subList.iterator(), separator);
+ }
+
+ /**
+ * <p>Joins the elements of the provided {@code List} into a single String
+ * containing the provided list of elements.</p>
+ *
+ * <p>No delimiter is added before or after the list.
+ * Null objects or empty strings within the array are represented by
+ * empty strings.</p>
+ *
+ * <pre>
+ * StringUtils.join(null, *) = null
+ * StringUtils.join([], *) = ""
+ * StringUtils.join([null], *) = ""
+ * StringUtils.join(["a", "b", "c"], ';') = "a;b;c"
+ * StringUtils.join(["a", "b", "c"], null) = "abc"
+ * StringUtils.join([null, "", "a"], ';') = ";;a"
+ * </pre>
+ *
+ * @param list the {@code List} of values to join together, may be null
+ * @param separator the separator character to use
+ * @param startIndex the first index to start joining from. It is
+ * an error to pass in an end index past the end of the list
+ * @param endIndex the index to stop joining from (exclusive). It is
+ * an error to pass in an end index past the end of the list
+ * @return the joined String, {@code null} if null list input
+ * @since 3.8
+ */
+ public static String join(final List<?> list, final String separator, final int startIndex, final int endIndex) {
+ if (list == null) {
+ return null;
+ }
+ final int noOfItems = endIndex - startIndex;
+ if (noOfItems <= 0) {
+ return EMPTY;
+ }
+ final List<?> subList = list.subList(startIndex, endIndex);
+ return join(subList.iterator(), separator);
+ }
+
+ /**
* <p>Joins the elements of the provided varargs into a
* single String containing the provided elements.</p>
*
http://git-wip-us.apache.org/repos/asf/commons-lang/blob/87937b2e/src/test/java/org/apache/commons/lang3/StringUtilsTest.java
----------------------------------------------------------------------
diff --git a/src/test/java/org/apache/commons/lang3/StringUtilsTest.java b/src/test/java/org/apache/commons/lang3/StringUtilsTest.java
index c4299b8..ee3beeb 100644
--- a/src/test/java/org/apache/commons/lang3/StringUtilsTest.java
+++ b/src/test/java/org/apache/commons/lang3/StringUtilsTest.java
@@ -34,6 +34,7 @@ import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
+import java.util.List;
import java.util.Locale;
import java.util.Objects;
import java.util.regex.PatternSyntaxException;
@@ -100,6 +101,11 @@ public class StringUtilsTest {
private static final char[] CHAR_PRIM_LIST = {'1', '2'};
private static final float[] FLOAT_PRIM_LIST = {1, 2};
private static final double[] DOUBLE_PRIM_LIST = {1, 2};
+ private static final List<String> MIXED_STRING_LIST = Arrays.asList(null, "", "foo");
+ private static final List<Object> MIXED_TYPE_OBJECT_LIST = Arrays.<Object>asList("foo", Long.valueOf(2L));
+ private static final List<String> STRING_LIST = Arrays.asList("foo", "bar", "baz");
+ private static final List<String> EMPTY_STRING_LIST = Collections.emptyList();
+ private static final List<String> NULL_STRING_LIST = Collections.singletonList(null);
private static final String SEPARATOR = ",";
private static final char SEPARATOR_CHAR = ';';
@@ -367,6 +373,38 @@ public class StringUtilsTest {
}
@Test
+ public void testJoin_List() {
+ assertNull(StringUtils.join((List<String>) null, null));
+ assertEquals(TEXT_LIST_NOSEP, StringUtils.join(STRING_LIST, null));
+ assertEquals(TEXT_LIST_NOSEP, StringUtils.join(STRING_LIST, ""));
+
+ assertEquals("", StringUtils.join(NULL_STRING_LIST, null));
+
+ assertEquals("", StringUtils.join(EMPTY_STRING_LIST, null));
+ assertEquals("", StringUtils.join(EMPTY_STRING_LIST, ""));
+ assertEquals("", StringUtils.join(EMPTY_STRING_LIST, SEPARATOR));
+
+ assertEquals(TEXT_LIST, StringUtils.join(STRING_LIST, SEPARATOR));
+ assertEquals(",,foo", StringUtils.join(MIXED_STRING_LIST, SEPARATOR));
+ assertEquals("foo,2", StringUtils.join(MIXED_TYPE_OBJECT_LIST, SEPARATOR));
+
+ assertEquals("/", StringUtils.join(MIXED_STRING_LIST, "/", 0, MIXED_STRING_LIST.size() - 1));
+ assertEquals("", StringUtils.join(MIXED_STRING_LIST, "", 0, MIXED_STRING_LIST.size()- 1));
+ assertEquals("foo", StringUtils.join(MIXED_TYPE_OBJECT_LIST, "/", 0, 1));
+ assertEquals("foo/2", StringUtils.join(MIXED_TYPE_OBJECT_LIST, "/", 0, 2));
+ assertEquals("2", StringUtils.join(MIXED_TYPE_OBJECT_LIST, "/", 1, 2));
+ assertEquals("", StringUtils.join(MIXED_TYPE_OBJECT_LIST, "/", 2, 1));
+ assertNull(null, StringUtils.join((List) null, "/", 0, 1));
+
+ assertEquals("/", StringUtils.join(MIXED_STRING_LIST, '/', 0, MIXED_STRING_LIST.size() - 1));
+ assertEquals("foo", StringUtils.join(MIXED_TYPE_OBJECT_LIST, '/', 0, 1));
+ assertEquals("foo/2", StringUtils.join(MIXED_TYPE_OBJECT_LIST, '/', 0, 2));
+ assertEquals("2", StringUtils.join(MIXED_TYPE_OBJECT_LIST, '/', 1, 2));
+ assertEquals("", StringUtils.join(MIXED_TYPE_OBJECT_LIST, '/', 2, 1));
+ assertNull(null, StringUtils.join((List) null, '/', 0, 1));
+ }
+
+ @Test
public void testJoin_IteratorChar() {
assertNull(StringUtils.join((Iterator<?>) null, ','));
assertEquals(TEXT_LIST_CHAR, StringUtils.join(Arrays.asList(ARRAY_LIST).iterator(), SEPARATOR_CHAR));