In the JDK, only a couple classes directly implement Iterable: Path, DirectoryStream, and Collection. DirectoryStream has a note that it doesn't support calling iterator() more than once, so I guess this is a possibility. I'll change it back to Collection.
On 6 January 2017 at 22:52, Matt Sicker <boa...@gmail.com> wrote: > Map doesn't implement collection. And the Iterator::hasNext is called on a > new Iterator obtained from the Iterable. It was implemented as a Collection > before, but I had a thought and implemented it as such. The javadocs for > Iterable don't exactly state whether or not the Iterator is a singleton, > but that would probably break something if used like that anyways. > > On 6 January 2017 at 22:37, Remko Popma <remko.po...@gmail.com> wrote: > >> Instead of Map::isEmpty, we could do Collection::isEmpty. Also is it a >> good idea to call Iterator::hasNext? In some implementations calling this >> method moves the cursor one position forward. Do we actually need to check >> that an Iterator is empty anywhere? >> >> Sent from my iPhone >> >> > On Jan 7, 2017, at 12:51, mattsic...@apache.org wrote: >> > >> > Repository: logging-log4j2 >> > Updated Branches: >> > refs/heads/master b0daba63f -> 61b3ab301 >> > >> > >> > Extract isEmpty() logic from RequiredValidator >> > >> > >> > Project: http://git-wip-us.apache.org/repos/asf/logging-log4j2/repo >> > Commit: http://git-wip-us.apache.org/repos/asf/logging-log4j2/commit >> /61b3ab30 >> > Tree: http://git-wip-us.apache.org/repos/asf/logging-log4j2/tree/6 >> 1b3ab30 >> > Diff: http://git-wip-us.apache.org/repos/asf/logging-log4j2/diff/6 >> 1b3ab30 >> > >> > Branch: refs/heads/master >> > Commit: 61b3ab301a4d54c28e736ca3a37f984475969377 >> > Parents: b0daba6 >> > Author: Matt Sicker <matt.sic...@spr.com> >> > Authored: Fri Jan 6 21:50:49 2017 -0600 >> > Committer: Matt Sicker <matt.sic...@spr.com> >> > Committed: Fri Jan 6 21:50:49 2017 -0600 >> > >> > ---------------------------------------------------------------------- >> > .../validators/RequiredValidator.java | 24 +------ >> > .../apache/logging/log4j/core/util/Assert.java | 46 +++++++++++++ >> > .../logging/log4j/core/util/AssertTest.java | 68 >> ++++++++++++++++++++ >> > 3 files changed, 116 insertions(+), 22 deletions(-) >> > ---------------------------------------------------------------------- >> > >> > >> > http://git-wip-us.apache.org/repos/asf/logging-log4j2/blob/6 >> 1b3ab30/log4j-core/src/main/java/org/apache/logging/log4j/co >> re/config/plugins/validation/validators/RequiredValidator.java >> > ---------------------------------------------------------------------- >> > diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/con >> fig/plugins/validation/validators/RequiredValidator.java >> b/log4j-core/src/main/java/org/apache/logging/log4j/core/con >> fig/plugins/validation/validators/RequiredValidator.java >> > index 5e6cec0..98c0a71 100644 >> > --- a/log4j-core/src/main/java/org/apache/logging/log4j/core/con >> fig/plugins/validation/validators/RequiredValidator.java >> > +++ b/log4j-core/src/main/java/org/apache/logging/log4j/core/con >> fig/plugins/validation/validators/RequiredValidator.java >> > @@ -22,6 +22,7 @@ import java.util.Map; >> > import org.apache.logging.log4j.Logger; >> > import org.apache.logging.log4j.core.config.plugins.validation.Cons >> traintValidator; >> > import org.apache.logging.log4j.core.config.plugins.validation.cons >> traints.Required; >> > +import org.apache.logging.log4j.core.util.Assert; >> > import org.apache.logging.log4j.status.StatusLogger; >> > >> > /** >> > @@ -49,28 +50,7 @@ public class RequiredValidator implements >> ConstraintValidator<Required> { >> > >> > @Override >> > public boolean isValid(final String name, final Object value) { >> > - if (value == null) { >> > - return err(name); >> > - } >> > - if (value instanceof CharSequence) { >> > - final CharSequence sequence = (CharSequence) value; >> > - return sequence.length() != 0 || err(name); >> > - } >> > - final Class<?> clazz = value.getClass(); >> > - if (clazz.isArray()) { >> > - final Object[] array = (Object[]) value; >> > - return array.length != 0 || err(name); >> > - } >> > - if (Collection.class.isAssignableFrom(clazz)) { >> > - final Collection<?> collection = (Collection<?>) value; >> > - return collection.size() != 0 || err(name); >> > - } >> > - if (Map.class.isAssignableFrom(clazz)) { >> > - final Map<?, ?> map = (Map<?, ?>) value; >> > - return map.size() != 0 || err(name); >> > - } >> > - // LOGGER.debug("Encountered type [{}] which can only be >> checked for null.", clazz.getName()); >> > - return true; >> > + return Assert.isNonEmpty(value) || err(name); >> > } >> > >> > private boolean err(final String name) { >> > >> > http://git-wip-us.apache.org/repos/asf/logging-log4j2/blob/6 >> 1b3ab30/log4j-core/src/main/java/org/apache/logging/log4j/co >> re/util/Assert.java >> > ---------------------------------------------------------------------- >> > diff --git >> > a/log4j-core/src/main/java/org/apache/logging/log4j/core/util/Assert.java >> b/log4j-core/src/main/java/org/apache/logging/log4j/core/util/Assert.java >> > index e37090f..d46c06a 100644 >> > --- a/log4j-core/src/main/java/org/apache/logging/log4j/core/uti >> l/Assert.java >> > +++ b/log4j-core/src/main/java/org/apache/logging/log4j/core/uti >> l/Assert.java >> > @@ -16,6 +16,8 @@ >> > */ >> > package org.apache.logging.log4j.core.util; >> > >> > +import java.util.Map; >> > + >> > /** >> > * Utility class providing common validation logic. >> > */ >> > @@ -23,6 +25,50 @@ public final class Assert { >> > private Assert() { >> > } >> > >> > + /** >> > + * Checks if an object has empty semantics. The following >> scenarios are considered empty: >> > + * <ul> >> > + * <li>{@code null}</li> >> > + * <li>empty {@link CharSequence}</li> >> > + * <li>empty array</li> >> > + * <li>empty {@link Iterable}</li> >> > + * <li>empty {@link Map}</li> >> > + * </ul> >> > + * >> > + * @param o value to check for emptiness >> > + * @return true if the value is empty, false otherwise >> > + * @since 2.8 >> > + */ >> > + public static boolean isEmpty(final Object o) { >> > + if (o == null) { >> > + return true; >> > + } >> > + if (o instanceof CharSequence) { >> > + return ((CharSequence) o).length() == 0; >> > + } >> > + if (o.getClass().isArray()) { >> > + return ((Object[]) o).length == 0; >> > + } >> > + if (o instanceof Iterable) { >> > + return !((Iterable<?>) o).iterator().hasNext(); >> > + } >> > + if (o instanceof Map) { >> > + return ((Map<?, ?>) o).isEmpty(); >> > + } >> > + return false; >> > + } >> > + >> > + /** >> > + * Opposite of {@link #isEmpty(Object)}. >> > + * >> > + * @param o value to check for non-emptiness >> > + * @return true if the value is non-empty, false otherwise >> > + * @since 2.8 >> > + */ >> > + public static boolean isNonEmpty(final Object o) { >> > + return !isEmpty(o); >> > + } >> > + >> > public static int valueIsAtLeast(final int value, final int >> minValue) { >> > if (value < minValue) { >> > throw new IllegalArgumentException("Value should be at >> least " + minValue + " but was " + value); >> > >> > http://git-wip-us.apache.org/repos/asf/logging-log4j2/blob/6 >> 1b3ab30/log4j-core/src/test/java/org/apache/logging/log4j/co >> re/util/AssertTest.java >> > ---------------------------------------------------------------------- >> > diff --git >> > a/log4j-core/src/test/java/org/apache/logging/log4j/core/util/AssertTest.java >> b/log4j-core/src/test/java/org/apache/logging/log4j/core/uti >> l/AssertTest.java >> > new file mode 100644 >> > index 0000000..242c41e >> > --- /dev/null >> > +++ b/log4j-core/src/test/java/org/apache/logging/log4j/core/uti >> l/AssertTest.java >> > @@ -0,0 +1,68 @@ >> > +/* >> > + * 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.logging.log4j.core.util; >> > + >> > +import java.util.ArrayList; >> > +import java.util.Collections; >> > +import java.util.HashMap; >> > + >> > +import org.junit.Test; >> > +import org.junit.runner.RunWith; >> > +import org.junit.runners.Parameterized; >> > + >> > +import static org.junit.Assert.*; >> > + >> > +/** >> > + * >> > + */ >> > +@RunWith(Parameterized.class) >> > +public class AssertTest { >> > + >> > + private final Object value; >> > + private final boolean isEmpty; >> > + >> > + @Parameterized.Parameters >> > + public static Object[][] data() { >> > + return new Object[][]{ >> > + // value, isEmpty >> > + {null, true}, >> > + {"", true}, >> > + {new Object[0], true}, >> > + {new ArrayList<>(), true}, >> > + {new HashMap<>(), true}, >> > + {0, false}, >> > + {1, false}, >> > + {false, false}, >> > + {true, false}, >> > + {new Object[]{null}, false}, >> > + {Collections.singletonList(null), false}, >> > + {Collections.singletonMap("", null), false}, >> > + {"null", false} >> > + }; >> > + } >> > + >> > + public AssertTest(final Object value, final boolean isEmpty) { >> > + this.value = value; >> > + this.isEmpty = isEmpty; >> > + } >> > + >> > + @Test >> > + public void isEmpty() throws Exception { >> > + assertEquals(isEmpty, Assert.isEmpty(value)); >> > + } >> > + >> > +} >> > \ No newline at end of file >> > >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: log4j-dev-unsubscr...@logging.apache.org >> For additional commands, e-mail: log4j-dev-h...@logging.apache.org >> >> > > > -- > Matt Sicker <boa...@gmail.com> > -- Matt Sicker <boa...@gmail.com>
