/*
* 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.el.stream;
import java.lang.reflect.Array;
import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;
import jakarta.el.ELContext;
import jakarta.el.ELResolver;
public class StreamELResolverImpl extends ELResolver {
@Override
public Object getValue(ELContext context, Object base, Object property) {
return null;
}
@Override
public Class<?> getType(ELContext context, Object base, Object property) {
return null;
}
@Override
public void setValue(ELContext context, Object base, Object property, Object value) {
// NO-OP
}
@Override
public boolean isReadOnly(ELContext context, Object base, Object property) {
return false;
}
@Override
public Class<?> getCommonPropertyType(ELContext context, Object base) {
return null;
}
@Override
public Object invoke(ELContext context, Object base, Object method, Class<?>[] paramTypes, Object[] params) {
if ("stream".equals(method) && params.length == 0) {
if (base.getClass().isArray()) {
context.setPropertyResolved(true);
return new Stream(new ArrayIterator(base));
} else if (base instanceof Collection) {
context.setPropertyResolved(true);
@SuppressWarnings("unchecked")
Collection<Object> collection = (Collection<Object>) base;
return new Stream(collection.iterator());
}
}
// Not for handling by this resolver
return null;
}
private static class ArrayIterator implements Iterator<Object> {
private final Object base;
private final int size;
private int index = 0;
ArrayIterator(Object base) {
this.base = base;
size = Array.getLength(base);
}
@Override
public boolean hasNext() {
return size > index;
}
@Override
public Object next() {
try {
return Array.get(base, index++);
} catch (ArrayIndexOutOfBoundsException e) {
throw new NoSuchElementException();
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
}