/*
* 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.ignite.internal.direct.state;
import java.lang.reflect.Array;
import java.util.Arrays;
import org.apache.ignite.internal.util.tostring.GridToStringExclude;
import org.apache.ignite.internal.util.typedef.internal.S;
import org.apache.ignite.lang.IgniteOutClosure;
/**
* Message state.
*/
public class DirectMessageState<T extends DirectMessageStateItem> {
/** Initial array size. */
private static final int INIT_SIZE = 10;
/** Item factory. */
@GridToStringExclude
private final IgniteOutClosure<T> factory;
/** Stack array. */
private T[] stack;
/** Current position. */
private int pos;
/**
* @param cls State item type.
* @param factory Item factory.
*/
@SuppressWarnings("unchecked")
public DirectMessageState(Class<T> cls, IgniteOutClosure<T> factory) {
this.factory = factory;
stack = (T[])Array.newInstance(cls, INIT_SIZE);
stack[0] = factory.apply();
}
/**
* @return Current item.
*/
public T item() {
return stack[pos];
}
/**
* Go forward.
*/
@SuppressWarnings("unchecked")
public void forward() {
pos++;
if (pos == stack.length) {
T[] stack0 = stack;
stack = (T[])Array.newInstance(stack.getClass().getComponentType(), stack.length << 1);
System.arraycopy(stack0, 0, stack, 0, stack0.length);
}
if (stack[pos] == null)
stack[pos] = factory.apply();
}
/**
* Go backward.
*
* @param reset Whether to reset current item.
*/
public void backward(boolean reset) {
if (reset)
stack[pos].reset();
pos--;
}
/**
* Resets state.
*/
public void reset() {
assert pos == 0;
stack[0].reset();
}
/** {@inheritDoc} */
@Override public String toString() {
return S.toString(DirectMessageState.class, this, "stack", Arrays.toString(stack));
}
}