Support output of vcard list

build.gradle

@@ -48,7 +48,8 @@ dependencies {
     // spock
     testImplementation platform("org.spockframework:spock-bom:$spockVersion"),
             "org.spockframework:spock-core",
-            "org.apache.logging.log4j:log4j-core:$log4jVersion"
+            "org.apache.logging.log4j:log4j-core:$log4jVersion",
+            "org.apache.logging.log4j:log4j-slf4j2-impl:$log4jVersion"
 
     testRuntimeOnly("org.mnode.ical4j:ical4j:$ical4jVersion") {
         capabilities {

gradle.properties

@@ -1,10 +1,9 @@
-ical4jVersion=4.0.3
-
-log4jVersion=2.22.1
-commonsIoVersion=2.15.1
-groovyVersion=3.0.20
+ical4jVersion=4.0.4
+log4jVersion=2.23.1
+commonsIoVersion=2.16.1
+groovyVersion=3.0.22
 bndVersion=6.3.1
-junitVintageVersion=5.10.2
+junitVintageVersion=5.10.3
 spockVersion=2.4-M1-groovy-3.0
 
 jacoco_htmlReport=true

src/main/java/net/fortuna/ical4j/vcard/VCardOutputter.java

@@ -75,7 +75,7 @@ public VCardOutputter(boolean validating, int foldLength) {
     }
 
     /**
-     * Outputs an iCalender string to the specified output stream.
+     * Outputs a vCard string to the specified output stream.
      * @param card a vCard object to output as a string
      * @param out an output stream the output stream to write the vCard string to
      * @throws IOException thrown when unable to write to output stream
@@ -86,7 +86,7 @@ public final void output(final VCard card, final OutputStream out) throws IOExce
     }
 
     /**
-     * Outputs an iCalender string to the specified writer.
+     * Outputs an vCard string to the specified writer.
      * @param card a vCard object to output as a string
      * @param out a writer to write the output string to
      * @throws IOException thrown when unable to write to writer
@@ -102,4 +102,33 @@ public final void output(final VCard card, final Writer out) throws IOException,
         }
     }
 
+    /**
+     * Outputs a vCard string to the specified output stream.
+     *
+     * @param cards a vCard object to output as a string
+     * @param out   an output stream the output stream to write the vCard string to
+     * @throws IOException         thrown when unable to write to output stream
+     * @throws ValidationException where the specified vCard is not valid
+     */
+    public final void output(final VCardList cards, final OutputStream out) throws IOException, ValidationException {
+        output(cards, new OutputStreamWriter(out, DEFAULT_CHARSET));
+    }
+
+    /**
+     * Outputs an vCard string to the specified writer.
+     *
+     * @param cards a vCard object to output as a string
+     * @param out   a writer to write the output string to
+     * @throws IOException         thrown when unable to write to writer
+     * @throws ValidationException where the specified vCard is not valid
+     */
+    public final void output(final VCardList cards, final Writer out) throws IOException, ValidationException {
+        if (isValidating()) {
+            cards.getAll().forEach(VCard::validate);
+        }
+
+        try (FoldingWriter writer = new FoldingWriter(out, foldLength)) {
+            writer.write(cards.toString());
+        }
+    }
 }

src/test/groovy/net/fortuna/ical4j/vcard/VCardOutputterSpec.groovy

@@ -0,0 +1,41 @@
+package net.fortuna.ical4j.vcard
+
+import spock.lang.Specification
+
+class VCardOutputterSpec extends Specification {
+
+    def 'test output of vcard list'() {
+        given: 'a list of cards'
+        def list = new VCardBuilder(getClass().getResourceAsStream('/samples/vcard-rfc2426.vcf'))
+                .buildAll()
+
+        expect: 'string output matches expected'
+        StringWriter w = []
+        new VCardOutputter(true).output(list, w)
+        w as String == '''BEGIN:VCARD\r
+VERSION:3.0\r
+FN:Frank Dawson\r
+N:Dawson;Frank;;;\r
+ORG:Lotus Development Corporation\r
+ADR;TYPE=WORK,POSTAL,PARCEL:;;6544 Battleford Drive;Raleigh;NC;27613-3502\r
+ ;U.S.A.;\r
+TEL;TYPE=VOICE,MSG,WORK:+1-919-676-9515\r
+TEL;TYPE=FAX,WORK:+1-919-676-9564\r
+EMAIL;TYPE=INTERNET,PREF:[email protected]\r
+EMAIL;TYPE=INTERNET:[email protected]\r
+URL:http://home.earthlink.net/~fdawson\r
+END:VCARD\r
+\r
+BEGIN:VCARD\r
+VERSION:3.0\r
+FN:Tim Howes\r
+N:Howes;Tim;;;\r
+ORG:Netscape Communications Corp.\r
+ADR;TYPE=WORK:;;501 E. Middlefield Rd.;Mountain View;CA; 94043;U.S.A.;\r
+TEL;TYPE=VOICE,MSG,WORK:+1-415-937-3419\r
+TEL;TYPE=FAX,WORK:+1-415-528-4164\r
+EMAIL;TYPE=INTERNET:[email protected]\r
+END:VCARD\r
+'''
+    }
+}

src/test/java/net/fortuna/ical4j/vcard/VCardOutputterTest.java

@@ -42,7 +42,6 @@
 import java.io.*;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.List;
 
 import static junit.framework.Assert.assertEquals;
 
@@ -74,24 +73,24 @@ public VCardOutputterTest(VCardOutputter outputter, VCard card, String expectedO
 
     @Test
     public void testOutput() throws IOException, ValidationException {
-        StringWriter out = new StringWriter();
+        var out = new StringWriter();
         outputter.output(card, out);
         assertEquals(expectedOutput, out.toString().replaceAll("\\r\\n ", ""));
     }
 
     @Parameters
     public static Collection<Object[]> parameters() throws IOException, ParserException {
-        VCardOutputter outputter = new VCardOutputter(false, 1000);
+        var outputter = new VCardOutputter(false, 1000);
         VCardBuilder builder = null;
-        List<Object[]> params = new ArrayList<Object[]>();
-        File[] testFiles = new File("src/test/resources/samples/valid").listFiles(
+        var params = new ArrayList<Object[]>();
+        var testFiles = new File("src/test/resources/samples/valid").listFiles(
                 (FileFilter) VCardFileFilter.INSTANCE);
         // enable relaxed parsing for non-standard GEO support..
         CompatibilityHints.setHintEnabled(CompatibilityHints.KEY_RELAXED_PARSING, true);
-        for (int i = 0; i < testFiles.length; i++) {
-            builder = new VCardBuilder(new FileReader(testFiles[i]));
-            VCard card = builder.build();
-            params.add(new Object[] {outputter, card, card.toString()});
+        for (var testFile : testFiles) {
+            builder = new VCardBuilder(new FileReader(testFile));
+            var card = builder.build();
+            params.add(new Object[]{outputter, card, card.toString()});
         }
         CompatibilityHints.setHintEnabled(CompatibilityHints.KEY_RELAXED_PARSING, false);
         return params;