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Posted to commits@polygene.apache.org by pa...@apache.org on 2016/11/28 16:07:57 UTC
[12/14] zest-java git commit: introduce single() Collector,
preferred over Iterables.single()
introduce single() Collector, preferred over Iterables.single()
Project: http://git-wip-us.apache.org/repos/asf/zest-java/repo
Commit: http://git-wip-us.apache.org/repos/asf/zest-java/commit/d7f000c9
Tree: http://git-wip-us.apache.org/repos/asf/zest-java/tree/d7f000c9
Diff: http://git-wip-us.apache.org/repos/asf/zest-java/diff/d7f000c9
Branch: refs/heads/develop
Commit: d7f000c987431cee7da87b8724e06ff96d5f864e
Parents: fdf596b
Author: Paul Merlin <pa...@apache.org>
Authored: Mon Nov 28 12:52:32 2016 +0100
Committer: Paul Merlin <pa...@apache.org>
Committed: Mon Nov 28 12:52:32 2016 +0100
----------------------------------------------------------------------
.../org/apache/zest/api/util/Collectors.java | 54 +++++++++++++++++
.../apache/zest/api/util/CollectorsTest.java | 64 ++++++++++++++++++++
.../zest/test/cache/MemoryCachePoolMixin.java | 4 +-
.../zest/library/rest/common/Resource.java | 9 +--
.../library/rest/common/link/LinksUtil.java | 9 +--
5 files changed, 130 insertions(+), 10 deletions(-)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/zest-java/blob/d7f000c9/core/api/src/main/java/org/apache/zest/api/util/Collectors.java
----------------------------------------------------------------------
diff --git a/core/api/src/main/java/org/apache/zest/api/util/Collectors.java b/core/api/src/main/java/org/apache/zest/api/util/Collectors.java
new file mode 100644
index 0000000..c977059
--- /dev/null
+++ b/core/api/src/main/java/org/apache/zest/api/util/Collectors.java
@@ -0,0 +1,54 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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.
+ */
+package org.apache.zest.api.util;
+
+import java.util.Optional;
+import java.util.function.Supplier;
+import java.util.stream.Collector;
+
+public class Collectors
+{
+ /**
+ * Collect a single element.
+ * @param <T> Element type
+ * @return The single element
+ * @throws IllegalArgumentException if no or more than one element
+ */
+ public static <T> Collector<T, ?, T> single()
+ throws IllegalArgumentException
+ {
+ Supplier<T> thrower = () ->
+ {
+ throw new IllegalArgumentException( "No or more than one element in stream" );
+ };
+ return java.util.stream.Collectors.collectingAndThen( singleOrEmpty(),
+ optional -> optional.orElseGet( thrower ) );
+ }
+
+ /**
+ * Collect an optional single element.
+ * @param <T> Element type
+ * @return An optional single element, empty if no or more than one element
+ */
+ public static <T> Collector<T, ?, Optional<T>> singleOrEmpty()
+ {
+ return java.util.stream.Collectors.reducing( ( a, b ) -> null );
+ }
+
+ private Collectors() {}
+}
http://git-wip-us.apache.org/repos/asf/zest-java/blob/d7f000c9/core/api/src/test/java/org/apache/zest/api/util/CollectorsTest.java
----------------------------------------------------------------------
diff --git a/core/api/src/test/java/org/apache/zest/api/util/CollectorsTest.java b/core/api/src/test/java/org/apache/zest/api/util/CollectorsTest.java
new file mode 100644
index 0000000..6aeb871
--- /dev/null
+++ b/core/api/src/test/java/org/apache/zest/api/util/CollectorsTest.java
@@ -0,0 +1,64 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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.
+ */
+package org.apache.zest.api.util;
+
+import java.util.Optional;
+import java.util.stream.Stream;
+import org.junit.Test;
+
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.fail;
+
+public class CollectorsTest
+{
+ @Test
+ public void singleOrEmpty()
+ {
+ assertEquals( Optional.empty(), Stream.of().collect( Collectors.singleOrEmpty() ) );
+ assertEquals( Optional.of( 1 ), Stream.of( 1 ).collect( Collectors.singleOrEmpty() ) );
+ assertEquals( Optional.empty(), Stream.of( 1, 1 ).collect( Collectors.singleOrEmpty() ) );
+ assertEquals( Optional.empty(), Stream.of( 1, 1, 1 ).collect( Collectors.singleOrEmpty() ) );
+ }
+
+ @Test
+ public void single()
+ {
+ assertThat( Stream.of( 1L ).collect( Collectors.single() ), is( 1L ) );
+
+ try
+ {
+ Stream.of().collect( Collectors.single() );
+ fail( "Should have failed" );
+ }
+ catch( IllegalArgumentException ex ) {}
+ try
+ {
+ Stream.of( 1, 1 ).collect( Collectors.single() );
+ fail( "Should have failed" );
+ }
+ catch( IllegalArgumentException ex ) {}
+ try
+ {
+ Stream.of( 1, 1, 1 ).collect( Collectors.single() );
+ fail( "Should have failed" );
+ }
+ catch( IllegalArgumentException ex ) {}
+ }
+}
http://git-wip-us.apache.org/repos/asf/zest-java/blob/d7f000c9/core/testsupport/src/main/java/org/apache/zest/test/cache/MemoryCachePoolMixin.java
----------------------------------------------------------------------
diff --git a/core/testsupport/src/main/java/org/apache/zest/test/cache/MemoryCachePoolMixin.java b/core/testsupport/src/main/java/org/apache/zest/test/cache/MemoryCachePoolMixin.java
index 46fe8b6..e462127 100644
--- a/core/testsupport/src/main/java/org/apache/zest/test/cache/MemoryCachePoolMixin.java
+++ b/core/testsupport/src/main/java/org/apache/zest/test/cache/MemoryCachePoolMixin.java
@@ -23,7 +23,7 @@ import java.util.concurrent.ConcurrentHashMap;
import org.apache.zest.api.util.NullArgumentException;
import org.apache.zest.spi.cache.Cache;
-import static org.apache.zest.functional.Iterables.single;
+import static org.apache.zest.api.util.Collectors.single;
/**
* In-Memory CachePool Mixin based on ConcurrentHashMap.
@@ -80,6 +80,6 @@ public abstract class MemoryCachePoolMixin
@Override
public MemoryCacheImpl<?> singleCache()
{
- return single( caches.values() );
+ return caches.values().stream().collect( single() );
}
}
http://git-wip-us.apache.org/repos/asf/zest-java/blob/d7f000c9/libraries/rest-common/src/main/java/org/apache/zest/library/rest/common/Resource.java
----------------------------------------------------------------------
diff --git a/libraries/rest-common/src/main/java/org/apache/zest/library/rest/common/Resource.java b/libraries/rest-common/src/main/java/org/apache/zest/library/rest/common/Resource.java
index 5bd62f2..8e611d0 100644
--- a/libraries/rest-common/src/main/java/org/apache/zest/library/rest/common/Resource.java
+++ b/libraries/rest-common/src/main/java/org/apache/zest/library/rest/common/Resource.java
@@ -26,10 +26,11 @@ import org.apache.zest.api.common.UseDefaults;
import org.apache.zest.api.mixin.Mixins;
import org.apache.zest.api.property.Property;
import org.apache.zest.api.value.ValueComposite;
-import org.apache.zest.functional.Iterables;
import org.apache.zest.library.rest.common.link.Link;
import org.apache.zest.library.rest.common.link.LinksUtil;
+import static org.apache.zest.api.util.Collectors.single;
+
/**
* Value representing a whole resource in a URL path. Allows listing of available
* queries, commands, sub-resources and an index.
@@ -62,19 +63,19 @@ public interface Resource
@Override
public Link query( String relation )
{
- return Iterables.single( Iterables.filter( LinksUtil.withRel( relation ), queries().get() ) );
+ return queries().get().stream().filter( LinksUtil.withRel( relation ) ).collect( single() );
}
@Override
public Link command( String relation )
{
- return Iterables.single(Iterables.filter( LinksUtil.withRel( relation ), commands().get() ));
+ return commands().get().stream().filter( LinksUtil.withRel( relation ) ).collect( single() );
}
@Override
public Link resource( String relation )
{
- return Iterables.single(Iterables.filter( LinksUtil.withRel( relation ), resources().get() ));
+ return resources().get().stream().filter( LinksUtil.withRel( relation ) ).collect( single() );
}
}
}
http://git-wip-us.apache.org/repos/asf/zest-java/blob/d7f000c9/libraries/rest-common/src/main/java/org/apache/zest/library/rest/common/link/LinksUtil.java
----------------------------------------------------------------------
diff --git a/libraries/rest-common/src/main/java/org/apache/zest/library/rest/common/link/LinksUtil.java b/libraries/rest-common/src/main/java/org/apache/zest/library/rest/common/link/LinksUtil.java
index 4f592a6..cfcc08d 100644
--- a/libraries/rest-common/src/main/java/org/apache/zest/library/rest/common/link/LinksUtil.java
+++ b/libraries/rest-common/src/main/java/org/apache/zest/library/rest/common/link/LinksUtil.java
@@ -22,7 +22,8 @@ package org.apache.zest.library.rest.common.link;
import java.util.function.Function;
import java.util.function.Predicate;
-import org.apache.zest.functional.Iterables;
+
+import static org.apache.zest.api.util.Collectors.single;
/**
* Helper methods for links
@@ -52,14 +53,14 @@ public final class LinksUtil
};
}
- public static Link withRel(String rel, Links links)
+ public static Link withRel( String rel, Links links )
{
- return Iterables.single( Iterables.filter( withRel( rel ), links.links().get() ) );
+ return links.links().get().stream().filter( withRel( rel ) ).collect( single() );
}
public static Link withId(String id, Links links)
{
- return Iterables.single( Iterables.filter( withId( id ), links.links().get() ) );
+ return links.links().get().stream().filter( withId( id ) ).collect( single() );
}
public static Function<Link, String> toRel()