org.apache.james.imap.api.message.IdRange Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of apache-james-imap-api Show documentation
The newest version!
/****************************************************************
 * 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.james.imap.api.message;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;

/**
 * Represents a range of UID or MSN values.
 */
public final class IdRange implements Iterable, Comparable{

    private long _lowVal;

    private long _highVal;

    public IdRange(long singleVal) {
        _lowVal = singleVal;
        _highVal = singleVal;
    }

    public IdRange(long lowVal, long highVal) {
        if (lowVal > highVal)
            throw new IllegalArgumentException("LowVal must be <= HighVal");
        _lowVal = lowVal;
        _highVal = highVal;
    }

    public long getLowVal() {
        return _lowVal;
    }

    public long getHighVal() {
        return _highVal;
    }

    public void setLowVal(long lowVal) {
        if (lowVal > _highVal)
            throw new IllegalArgumentException("LowVal must be <= HighVal");
        _lowVal = lowVal;
    }

    public void setHighVal(long highVal) {
        if (_lowVal > highVal)
            throw new IllegalArgumentException("HighVal must be >= LowVal");
        _highVal = highVal;
    }

    /**
     * Return true if the {@link IdRange} includes the given value
     * 
     * @param value
     * @return include
     */
    public boolean includes(long value) {
        return _lowVal <= value && value <= _highVal;
    }

    /**
     * @see java.lang.Object#hashCode()
     */
    public int hashCode() {
        final int PRIME = 31;
        int result = 1;
        result = PRIME * result + (int) (_highVal ^ (_highVal >>> 32));
        result = PRIME * result + (int) (_lowVal ^ (_lowVal >>> 32));
        return result;
    }

    /**
     * @see java.lang.Object#equals(java.lang.Object)
     */
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        final IdRange other = (IdRange) obj;
        if (_highVal != other._highVal)
            return false;
        if (_lowVal != other._lowVal)
            return false;
        return true;
    }

    /**
     * Renders text suitable for logging.
     * 
     * @return a String representation of this object.
     */
    public String toString() {
        final String retValue = "IdRange ( " + this._lowVal + "->" + this._highVal + " )";

        return retValue;
    }

    public String getFormattedString() {
        if (this._lowVal == this._highVal)
            return Long.toString(this._lowVal);
        else
            return this._lowVal + ":" + this._highVal;
    }

    /**
     * Utility method which will copy the given {@link List} and try to merge
     * the {@link IdRange} in the copy before return it.
     * 
     * 
     * @param ranges
     * @return mergedRanges
     */
    public static List mergeRanges(final List ranges) {
        List copy = new ArrayList(ranges);
        Collections.sort(copy);

        boolean lastUid = false;

        for (int i = 0; i < copy.size() - 1; i++) {
            IdRange current = copy.get(i);
            IdRange next = copy.get(i + 1);
            if (next.getLowVal() == Long.MAX_VALUE && next.getHighVal() == Long.MAX_VALUE) {
                if (lastUid) {
                    copy.remove(next);
                    i--;
                } else {
                    lastUid = true;
                }
            } else {
                // Make sure we handle the "*" and "*:*" correctly and don't
                // remove ranges by error. See IMAP-289
                if ((current.getLowVal() != Long.MAX_VALUE && current.getHighVal() != Long.MAX_VALUE) && (current.getHighVal() >= next.getLowVal() - 1)) {
                    if (next.getHighVal() > current.getHighVal()) {
                        current.setHighVal(next.getHighVal());
                    }
                    // remove the merged id range and decrease the count
                    copy.remove(next);
                    i--;
                }
            }

        }
        return copy;

    }


    /**
     * Return a read-only {@link Iterator} which contains all msn/uid which fail in the specified range.
     * 
     * @return rangeIt
     */
    @Override
    public Iterator iterator() {
        long from = getLowVal();
        if (from == Long.MAX_VALUE) {
            from = 1;
        }
        long to = getHighVal();
        return new RangeIterator(from, to);
    }
    
    /**
     * {@link Iterator} of a range of msn/uid
     *
     */
    private final class RangeIterator implements Iterator {

        private long to;
        private long current;
        
        public RangeIterator(long from, long to) {
            this.to = to;
            this.current = from;
        }
        
        @Override
        public boolean hasNext() {
            return current <= to;
        }

        @Override
        public Long next() {
            if (hasNext()) {
                return current++;
            } else {
                throw new NoSuchElementException("Highest id of " + to + " was reached before");
            }
        }

        @Override
        public void remove() {
            throw new UnsupportedOperationException("Read-Only");
        }
        
    }

    @Override
    public int compareTo(IdRange range2) {
        // Correctly sort and respect "*" and "*:*" ranges. See IMAP-289
        if (getLowVal() == Long.MAX_VALUE && getHighVal() == Long.MAX_VALUE && range2.getLowVal() == Long.MAX_VALUE && range2.getHighVal() == Long.MAX_VALUE) {
            return 0;
        }
        if (getLowVal() == Long.MAX_VALUE && getHighVal() == Long.MAX_VALUE) {
            return 1;
        } else if (range2.getLowVal() == Long.MAX_VALUE && range2.getHighVal() == Long.MAX_VALUE) {
            return -1;
        } else {
            return (int) (getLowVal() - range2.getLowVal());
        }
    }

}