Guten Tag Thorsten Schöning,
am Freitag, 4. September 2020 um 10:40 schrieben Sie:
> That's why I asked: I most likely prefer an explicit container to add
> transformers to currently, something like "MultiAbstract[...]" or
> "[...]BehaviorMulti" or alike. That collects individual transformers
> and gets itself only added to the component.
I've created a container to work around the current limitation, which
is pretty easy overall and easily compatible with different versions
of Wicket. A corresponding PR is made, if it doesn't make it into the
project, simply copy&paste it into an individual class into your own
projects and use it.
https://github.com/apache/wicket/pull/457
Mit freundlichen Grüßen,
Thorsten Schöning
--
Thorsten Schöning E-Mail: thorsten.schoen...@am-soft.de
AM-SoFT IT-Systeme http://www.AM-SoFT.de/
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.../transformer/AbstractTransformerBehavior.java | 112 ++++++++++++++++++++-
.../AbstractTransformerBehaviorTest.java | 88 +++++++++++++++-
2 files changed, 190 insertions(+), 10 deletions(-)
diff --git
a/wicket-core/src/main/java/org/apache/wicket/markup/transformer/AbstractTransformerBehavior.java
b/wicket-core/src/main/java/org/apache/wicket/markup/transformer/AbstractTransformerBehavior.java
index 0359bbbcd6..d18c3dd664 100644
---
a/wicket-core/src/main/java/org/apache/wicket/markup/transformer/AbstractTransformerBehavior.java
+++
b/wicket-core/src/main/java/org/apache/wicket/markup/transformer/AbstractTransformerBehavior.java
@@ -16,6 +16,11 @@
*/
package org.apache.wicket.markup.transformer;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Objects;
+
import org.apache.wicket.Component;
import org.apache.wicket.Page;
import org.apache.wicket.WicketRuntimeException;
@@ -26,17 +31,114 @@ import org.apache.wicket.request.cycle.RequestCycle;
import org.apache.wicket.request.http.WebResponse;
/**
- * A {@link Behavior} which can be added to any component. It allows to
post-process (transform) the
+ * A {@link Behavior} which can be added to any component, allowing to
post-process (transform) the
* markup generated by the component.
- *
+ * <p>
+ * There's one important limitation with the current implementation: Multiple
different instances of
+ * this behavior CAN NOT be assigned to the same component! If one whiches to
do so, the contained
+ * container needs to be used to wrap existing behaviors and that container
needs to be added to the
+ * component instead. The current implementation of works with temporary
responses, but does not
+ * support nesting itself properly, which results in missing rendered output
and most likely broken
+ * HTML documents in the end.
+ * </p>
* @see org.apache.wicket.markup.transformer.AbstractOutputTransformerContainer
- *
+ * @see <a
href="https://issues.apache.org/jira/projects/WICKET/issues/WICKET-6823";>JIRA
issue</a>
+ *
* @author Juergen Donnerstag
*/
public abstract class AbstractTransformerBehavior extends Behavior implements
ITransformer
{
private static final long serialVersionUID = 1L;
+ /**
+ * Container to apply multiple {@link AbstractTransformerBehavior} to
some component.
+ * <p>
+ * This container is by design NOT about multiple arbitrary
transformations, but really only for the
+ * one use case supporting multiple instances of {@link
AbstractTransformerBehavior} on one and the
+ * same component. The current implementation of that works with
temporary responses, but doesn't
+ * support nesting itself properly in case multiple behaviors assigned
to the same component, which
+ * results in missing rendered output and most likely entirely broken
HTML documents in the end.
+ * </p>
+ * <p>
+ * The easiest workaround for that problem is simply introducing this
container which users need to
+ * use in those cases: An instance needs to be created with all
transformers of interest in the
+ * order they should be applied and the container takes care of doing
so. Because the container is
+ * an {@link AbstractTransformerBehavior} itself, things simply work
like with individual behaviors,
+ * while response handling is only managed by the container. So when
used with this container, the
+ * callbacks of the maintained instances like {@link
AbstractTransformerBehavior#afterRender(Component)}
+ * etc., are NOT used anymore! OTOH, the individual behaviors stay
useful without the container as
+ * well.
+ * </p>
+ * @see <a
href="https://issues.apache.org/jira/projects/WICKET/issues/WICKET-6823";>JIRA
issue</a>
+ */
+ public static class Multi extends AbstractTransformerBehavior
+ {
+ private static final long serialVersionUID = 1L;
+
+ /**
+ * All transformers which need to be applied in the order they
need to be applied.
+ */
+ private final List<AbstractTransformerBehavior> transes;
+
+ /**
+ * CTOR simply storing the given transformers.
+ *
+ * @param transes, which must not be {@code null} or empty, as
neither make sense here.
+ */
+ private Multi(List<AbstractTransformerBehavior> transes)
+ {
+ if ((transes == null) || transes.isEmpty())
+ {
+ throw new IllegalArgumentException("No
transformers given.");
+ }
+
+ this.transes = transes;
+ }
+
+ @Override
+ public CharSequence transform(Component component, CharSequence
output) throws Exception
+ {
+ CharSequence retVal = output;
+ for (AbstractTransformerBehavior trans : this.transes)
+ {
+ retVal = trans.transform(component, retVal);
+ }
+
+ return retVal;
+ }
+
+ /**
+ * Create a new container with the given transformers and with
keeping their order.
+ * <p>
+ * This factory expects multiple individual transformers
already, because creating a container
+ * with less doesn't make too much sense and users should
reconsider then if this container is
+ * of use at all. In most cases users do have individual
transformers to apply only anyway and
+ * don't need to provide a collection themself this way. OTOH,
a collection could be empty or
+ * contain only one element would then defeat the purpose of
this container again.
+ * </p>
+ * @param first First transformer to apply.
+ * @param second Second transformer to apply.
+ * @param moreIf All other transformers to apply, if at all, in
given order.
+ * @return A container with multiple transformers being applied.
+ */
+ public static Multi newFor( AbstractTransformerBehavior
first,
+
AbstractTransformerBehavior second,
+
AbstractTransformerBehavior... moreIf)
+ {
+ List<AbstractTransformerBehavior> transes = new
ArrayList<>();
+
+ transes.add(Objects.requireNonNull(first, "No
first transformer given."));
+ transes.add(Objects.requireNonNull(second, "No
second transformer given."));
+
+ if ((moreIf != null) && (moreIf.length > 0))
+ {
+ transes.addAll(Arrays.asList(moreIf));
+ }
+
+ return new Multi(transes);
+ }
+ }
+
/**
* The request cycle's response before the transformation.
*/
@@ -45,10 +147,10 @@ public abstract class AbstractTransformerBehavior extends
Behavior implements IT
/**
* Create a new response object which is used to store the markup
generated by the child
* objects.
- *
+ *
* @param originalResponse
* the original web response or {@code null} if it isn't a
{@link WebResponse}
- *
+ *
* @return Response object. Must not be null
*/
protected BufferedWebResponse newResponse(final WebResponse
originalResponse)
diff --git
a/wicket-core/src/test/java/org/apache/wicket/markup/transformer/AbstractTransformerBehaviorTest.java
b/wicket-core/src/test/java/org/apache/wicket/markup/transformer/AbstractTransformerBehaviorTest.java
index adc30243a8..2c5b4d63cf 100644
---
a/wicket-core/src/test/java/org/apache/wicket/markup/transformer/AbstractTransformerBehaviorTest.java
+++
b/wicket-core/src/test/java/org/apache/wicket/markup/transformer/AbstractTransformerBehaviorTest.java
@@ -16,6 +16,8 @@
*/
package org.apache.wicket.markup.transformer;
+import java.util.function.Function;
+
import org.apache.wicket.Component;
import org.apache.wicket.MarkupContainer;
import org.apache.wicket.ajax.AjaxRequestTarget;
@@ -37,7 +39,10 @@ public class AbstractTransformerBehaviorTest extends
WicketTestCase
@Test
public void responseTransformation()
{
- TestPage testPage = new TestPage();
+ TestPage testPage = new TestPage();
+ String replacement = "replacement";
+
+ testPage.add(new Label(TestPage.LABEL_ID, TestPage.LABEL_VAL));
testPage.add(new AbstractTransformerBehavior()
{
/** */
@@ -47,11 +52,12 @@ public class AbstractTransformerBehaviorTest extends
WicketTestCase
public CharSequence transform(Component component,
CharSequence output)
throws Exception
{
- return output.toString().replace("to be
replaced", "replacement");
+ return
output.toString().replace(TestPage.LABEL_VAL, replacement);
}
});
+
tester.startPage(testPage);
-
assertTrue(tester.getLastResponseAsString().contains("replacement"));
+
assertTrue(tester.getLastResponseAsString().contains(replacement));
}
/**
@@ -69,7 +75,77 @@ public class AbstractTransformerBehaviorTest extends
WicketTestCase
tester.clickLink("updateLabel", true);
tester.assertContains("ajax request");
tester.assertContainsNot("normal request");
+ }
+ /**
+ * Test how multiple different transformers applied to the same
component behave.
+ * <p>
+ * The current implementation of {@link AbstractTransformerBehavior}
doesn't support multiple
+ * instances on the same component, a container needs to be used
explicitly instead. So make
+ * sure the implementation is as expected, as otherwise the container
might not be necessary at
+ * all anymore, and that the container really works around the problem.
+ * </p>
+ * @see <a
href="https://issues.apache.org/jira/projects/WICKET/issues/WICKET-6823";>JIRA
issue</a>
+ */
+ @Test
+ public void multiTransesSameComp()
+ {
+ TestPage testPage = new TestPage();
+ Label label = new Label(TestPage.LABEL_ID,
TestPage.LABEL_VAL);
+
+ Function<String, AbstractTransformerBehavior> transProd = (val)
->
+ {
+ return new AbstractTransformerBehavior()
+ {
+ /** */
+ private static final long serialVersionUID = 1L;
+
+ @Override
+ public CharSequence transform(Component
component, CharSequence output)
+ throws Exception
+ {
+ String outStr = output.toString();
+ if (outStr.contains(TestPage.LABEL_VAL))
+ {
+ return
outStr.replace(TestPage.LABEL_VAL, val);
+ }
+
+ // Make somewhat sure to recognize that
BOTH transformers have been applied.
+ return outStr.replaceAll
+ (
+ ">(.+)</span>",
+ String.format(">$1%s</span>",
val)
+ );
+ }
+ };
+ };
+
+ label.add(transProd.apply("foo"));
+ label.add(transProd.apply("bar"));
+
+ // Make sure the expected limited implementation is still
available, which makes a container
+ // necessary only at all. If that has changed, the container
might be removed as well.
+ testPage.add(label);
+ tester.startPage(testPage);
+ tester.isVisible(TestPage.LABEL_ID);
+ tester.assertContains(">foo</span>");
+ tester.assertContainsNot("</html>");
+
+ testPage = new TestPage();
+ label = new Label(TestPage.LABEL_ID,
TestPage.LABEL_VAL);
+
+ label.add(AbstractTransformerBehavior.Multi.newFor
+ (
+ transProd.apply("foo"),
+ transProd.apply("bar")
+ ));
+
+ // Maike sure that the container provided as workaround really
fixes the problem.
+ testPage.add(label);
+ tester.startPage(testPage);
+ tester.isVisible(TestPage.LABEL_ID);
+ tester.assertContains(">foobar</span>");
+ tester.assertContains("</html>");
}
private static class AjaxTestPage extends WebPage implements
IMarkupResourceStreamProvider
@@ -126,12 +202,14 @@ public class AbstractTransformerBehaviorTest extends
WicketTestCase
{
private static final long serialVersionUID = 1L;
+ private static final String LABEL_ID = "label";
+ private static final String LABEL_VAL = "{to be replaced}";
+
@Override
public IResourceStream getMarkupResourceStream(MarkupContainer
container,
Class<?> containerClass)
{
- return new StringResourceStream("<html><body>{to be
replaced}</body></html>");
+ return new StringResourceStream("<html><body><span
wicket:id='label'></span></body></html>");
}
-
}
}
