alternative

src/main/java/io/jenkins/plugins/checks/api/ChecksOutput.java

@@ -15,12 +15,12 @@
  */
 public class ChecksOutput {
     private final String title;
-    private final List<String> summary;
-    private final List<String> text;
+    private final TruncatedString summary;
+    private final TruncatedString text;
     private final List<ChecksAnnotation> annotations;
     private final List<ChecksImage> images;
 
-    private ChecksOutput(final String title, final List<String> summary, final List<String> text,
+    private ChecksOutput(final String title, final TruncatedString summary, final TruncatedString text,
             final List<ChecksAnnotation> annotations, final List<ChecksImage> images) {
         this.title = title;
         this.summary = summary;
@@ -37,8 +37,8 @@ private ChecksOutput(final String title, final List<String> summary, final List<
      */
     public ChecksOutput(final ChecksOutput that) {
         this(that.getTitle().orElse(null),
-                that.getSummary().map(Collections::singletonList).orElse(null),
-                that.getText().map(Collections::singletonList).orElse(null),
+                that.getSummary().map(TruncatedString::fromString).orElse(null),
+                that.getText().map(TruncatedString::fromString).orElse(null),
                 that.getChecksAnnotations(), that.getChecksImages());
     }
 
@@ -60,19 +60,19 @@ private static String truncateText(List<String> chunks, int maxLength, String tr
     }
 
     public Optional<String> getSummary() {
-        return Optional.ofNullable(summary).map(StringUtils::join);
+        return Optional.ofNullable(summary).map(TruncatedString::build);
     }
 
-    public Optional<String> getSummary(int maxLength, String truncateText) {
-        return Optional.ofNullable(summary).map(s -> truncateText(s, maxLength, truncateText));
+    public Optional<String> getSummary(TruncatedString.Truncator truncator) {
+        return Optional.ofNullable(summary).map(truncator::truncate);
     }
 
     public Optional<String> getText() {
-        return Optional.ofNullable(text).map(StringUtils::join);
+        return Optional.ofNullable(text).map(TruncatedString::build);
     }
 
-    public Optional<String> getText(int maxLength, String truncateText) {
-        return Optional.ofNullable(text).map(s -> truncateText(s, maxLength, truncateText));
+    public Optional<String> getText(TruncatedString.Truncator truncator) {
+        return Optional.ofNullable(text).map(truncator::truncate);
     }
 
     public List<ChecksAnnotation> getChecksAnnotations() {
@@ -99,8 +99,8 @@ public String toString() {
      */
     public static class ChecksOutputBuilder {
         private String title;
-        private List<String> summary;
-        private List<String> text;
+        private TruncatedString summary;
+        private TruncatedString text;
         private List<ChecksAnnotation> annotations;
         private List<ChecksImage> images;
 
@@ -139,15 +139,11 @@ public ChecksOutputBuilder withTitle(final String title) {
          */
         @SuppressWarnings("HiddenField") // builder pattern
         public ChecksOutputBuilder withSummary(final String summary) {
-            this.summary = new ArrayList<>();
-            return appendSummary(summary);
+            return withSummary(new TruncatedString.Builder().addText(summary).build());
         }
 
-        public ChecksOutputBuilder appendSummary(final String summary) {
-            if (this.summary == null) {
-                this.summary = new ArrayList<>();
-            }
-            this.summary.add(requireNonNull(summary));
+        public ChecksOutputBuilder withSummary(final TruncatedString summary) {
+            this.summary = requireNonNull(summary);
             return this;
         }
 
@@ -164,15 +160,11 @@ public ChecksOutputBuilder appendSummary(final String summary) {
          */
         @SuppressWarnings("HiddenField") // builder pattern
         public ChecksOutputBuilder withText(final String text) {
-            this.text = new ArrayList<>();
-            return appendText(text);
+            return withText(new TruncatedString.Builder().addText(text).build());
         }
 
-        public ChecksOutputBuilder appendText(final String text) {
-            if (this.text == null) {
-                this.text = new ArrayList<>();
-            }
-            this.text.add(requireNonNull(text));
+        public ChecksOutputBuilder withText(final TruncatedString text) {
+            this.text = requireNonNull(text);
             return this;
         }
 

src/main/java/io/jenkins/plugins/checks/api/TruncatedString.java

@@ -0,0 +1,93 @@
+package io.jenkins.plugins.checks.api;
+
+import org.apache.commons.lang3.StringUtils;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class TruncatedString {
+
+    private final List<CharSequence> chunks;
+    private final String readMoreLink;
+
+    /**
+     * Create a {@link TruncatedString} with the provided limit and truncation message.
+     *
+     * @param truncatedMessage the message to be appended should maxSize be exceeded, e.g.
+     *                         "Some output is not shown here, see more on [Jenkins](url)."
+     */
+    private TruncatedString(final String readMoreLink, final List<CharSequence> chunks) {
+        this.readMoreLink = readMoreLink;
+        this.chunks = chunks;
+    }
+
+    static TruncatedString fromString(String string) {
+        return new TruncatedString.Builder().addText(string).build();
+    }
+
+    public static class Builder {
+        private String readMoreLink;
+        private final List<CharSequence> chunks = new ArrayList<>();
+
+        public TruncatedString build() {
+            return new TruncatedString(readMoreLink, chunks);
+        }
+
+        public Builder withReadMoreLink(String readMoreLink) {
+            this.readMoreLink = readMoreLink;
+            return this;
+        }
+
+        public Builder addText(CharSequence chunk) {
+            this.chunks.add(chunk);
+            return this;
+        }
+
+    }
+
+    public static abstract class Truncator {
+
+        protected final int maxSize;
+
+        public Truncator(int maxSize) {
+            this.maxSize = maxSize;
+        }
+
+        public abstract String getReadMoreText(TruncatedString truncatedString);
+
+        public String truncate(TruncatedString truncatedString) {
+            String readMoreText = getReadMoreText(truncatedString);
+            if (truncatedString.chunks.size() == 0) {
+                return null;
+            }
+            StringBuilder builder = new StringBuilder();
+            for (CharSequence chunk: truncatedString.chunks) {
+                if (builder.length() + chunk.length() + readMoreText.length() < maxSize) {
+                    builder.append(chunk);
+                } else {
+                    builder.append(readMoreText);
+                    break;
+                }
+            }
+            return builder.toString();
+        }
+    }
+
+    /* example implementation */
+    public static class GitHubTruncator extends Truncator {
+
+        public GitHubTruncator() {
+            super(65536);
+        }
+
+        @Override
+        public String getReadMoreText(TruncatedString truncatedString) {
+            return String.format("%n%nOutput truncated - [more information](%s)", truncatedString.readMoreLink);
+        }
+    }
+
+    public String build() {
+        return StringUtils.join(chunks);
+    }
+
+}