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/**
* @copyright
* ====================================================================
* 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.
* ====================================================================
* @endcopyright
*
* @file Iterator.cpp
* @brief Implementation of the class Iterator
*/
#include "Iterator.h"
namespace {
jobject init_iterator(jobject jiterable, bool persistent)
{
// A null iterable is allowed, we'll leave the iterator null and
// nothing will happen in hasNext() and next().
if (!jiterable)
return NULL;
JNIEnv* env = JNIUtil::getEnv();
static jmethodID iterator_mid = 0;
if (0 == iterator_mid)
{
jclass cls = env->FindClass("java/lang/Iterable");
if (JNIUtil::isExceptionThrown())
return NULL;
iterator_mid = env->GetMethodID(cls, "iterator",
"()Ljava/util/Iterator;");
if (JNIUtil::isExceptionThrown())
return NULL;
}
jobject jiterator = env->CallObjectMethod(jiterable, iterator_mid);
if (JNIUtil::isExceptionThrown())
return NULL;
return (persistent ? env->NewGlobalRef(jiterator) : jiterator);
}
} // anonymous namespace
Iterator::Iterator(jobject jiterable)
: m_persistent(false),
m_jiterator(init_iterator(jiterable, false))
{}
Iterator::Iterator(jobject jiterable, bool)
: m_persistent(true),
m_jiterator(init_iterator(jiterable, true))
{}
Iterator::~Iterator()
{
if (m_persistent && m_jiterator)
JNIUtil::getEnv()->DeleteGlobalRef(m_jiterator);
}
bool Iterator::hasNext() const
{
if (!m_jiterator)
return false;
JNIEnv* env = JNIUtil::getEnv();
static jmethodID hasNext_mid = 0;
if (0 == hasNext_mid)
{
jclass cls = env->FindClass("java/util/Iterator");
if (JNIUtil::isExceptionThrown())
return false;
hasNext_mid = env->GetMethodID(cls, "hasNext", "()Z");
if (JNIUtil::isExceptionThrown())
return false;
}
return bool(env->CallBooleanMethod(m_jiterator, hasNext_mid));
}
jobject Iterator::next() const
{
if (!m_jiterator)
return NULL;
JNIEnv* env = JNIUtil::getEnv();
static jmethodID next_mid = 0;
if (0 == next_mid)
{
jclass cls = env->FindClass("java/util/Iterator");
if (JNIUtil::isExceptionThrown())
return NULL;
next_mid = env->GetMethodID(cls, "next", "()Ljava/lang/Object;");
if (JNIUtil::isExceptionThrown())
return NULL;
}
return env->CallObjectMethod(m_jiterator, next_mid);
}
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