org.apache.ranger.authorization.hbase.ColumnIterator.java Source code

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Here is the source code for org.apache.ranger.authorization.hbase.ColumnIterator.java

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/*
 * 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.ranger.authorization.hbase;

import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Set;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.util.Bytes;

public class ColumnIterator implements Iterator<String> {
    // TODO write tests for this class

    private static final Log LOG = LogFactory.getLog(ColumnIterator.class.getName());
    Iterator<byte[]> _setIterator;
    Iterator<KeyValue> _listIterator;

    @SuppressWarnings("unchecked")
    public ColumnIterator(Collection<?> columnCollection) {
        if (columnCollection != null) {
            if (columnCollection instanceof Set) {
                _setIterator = ((Set<byte[]>) columnCollection).iterator();
            } else if (columnCollection instanceof List) {
                _listIterator = ((List<KeyValue>) columnCollection).iterator();
            } else { // unexpected
                // TODO make message better
                LOG.error("Unexpected type " + columnCollection.getClass().getName()
                        + " passed as value in column family collection");
            }
        }
    }

    @Override
    public boolean hasNext() {
        if (_setIterator != null) {
            return _setIterator.hasNext();
        } else if (_listIterator != null) {
            return _listIterator.hasNext();
        } else {
            return false;
        }
    }

    /**
     * Never returns a null value.  Will return empty string in case of null value.
     */
    @Override
    public String next() {
        String value = "";
        if (_setIterator != null) {
            byte[] valueBytes = _setIterator.next();
            if (valueBytes != null) {
                value = Bytes.toString(valueBytes);
            }
        } else if (_listIterator != null) {
            KeyValue kv = _listIterator.next();
            byte[] v = kv.getQualifier();
            if (v != null) {
                value = Bytes.toString(v);
            }
        } else {
            // TODO make the error message better
            throw new NoSuchElementException("Empty values passed in!");
        }
        return value;
    }

    @Override
    public void remove() {
        // TODO make the error message better
        throw new UnsupportedOperationException("Remove not supported from iterator!");
    }

}