org.modeshape.jcr.cache.document.PatternIterator Maven / Gradle / Ivy
/*
* ModeShape (http://www.modeshape.org)
*
* Licensed 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.modeshape.jcr.cache.document;
import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.regex.Pattern;
/**
* A base class for an {@link Iterator} implementation that exposes values from another iterator that match at least one of the
* supplied patterns.
*
* @param the type of values
*/
abstract class PatternIterator extends DelegatingIterator {
private final Collection> patterns;
private Type last;
protected PatternIterator( Iterator delegate,
Collection> patterns ) {
super(delegate);
this.patterns = patterns;
}
@Override
public boolean hasNext() {
if (last != null) {
return true;
}
while (super.hasNext()) {
last = super.next();
String childName = matchable(last);
for (Object pattern : patterns) {
if (pattern instanceof String) {
// Check for an exact match ...
if (childName.equals(pattern)) return true;
} else {
Pattern p = (Pattern)pattern;
if (p.matcher(childName).matches()) return true;
}
}
}
last = null;
return false;
}
@Override
public Type next() {
try {
if (last == null) {
if (!hasNext()) {
throw new NoSuchElementException();
}
}
if (last != null) {
return last;
}
} finally {
last = null;
}
throw new NoSuchElementException();
}
protected abstract String matchable( Type value );
}
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