spring-batch RangeArrayPropertyEditor 源码

spring-batch RangeArrayPropertyEditor 代码

文件路径：/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/RangeArrayPropertyEditor.java

/*
 * Copyright 2006-2007 the original author or authors.
 *
 * Licensed 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
 *
 *      https://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.springframework.batch.item.file.transform;

import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

import java.beans.PropertyEditorSupport;
import java.util.Arrays;
import java.util.Comparator;

/**
 * Property editor implementation which parses string and creates array of ranges. Ranges
 * can be provided in any order. <br>
 * Input string should be provided in following format: 'range1, range2, range3,...' where
 * range is specified as:
 * <ul>
 * <li>'X-Y', where X is minimum value and Y is maximum value (condition X&lt;=Y is
 * verified)</li>
 * <li>or 'Z', where Z is minimum and maximum is calculated as (minimum of adjacent range
 * - 1). Maximum of the last range is never calculated. Range stays unbound at maximum
 * side if maximum value is not provided.</li>
 * </ul>
 * Minimum and maximum values can be from interval &lt;1, Integer.MAX_VALUE-1&gt;
 * <p>
 * Examples:<br>
 * '1, 15, 25, 38, 55-60' is equal to '1-14, 15-24, 25-37, 38-54, 55-60' <br>
 * '36, 14, 1-10, 15, 49-57' is equal to '36-48, 14-14, 1-10, 15-35, 49-57'
 * <p>
 * Property editor also allows to validate whether ranges are disjoint. Validation can be
 * turned on/off by using {@link #setForceDisjointRanges(boolean)}. By default validation
 * is turned off.
 *
 * @author peter.zozom
 */
public class RangeArrayPropertyEditor extends PropertyEditorSupport {

	private boolean forceDisjointRanges = false;

	/**
	 * Set force disjoint ranges. If set to TRUE, ranges are validated to be disjoint. For
	 * example: defining ranges '1-10, 5-15' will cause IllegalArgumentException in case
	 * of forceDisjointRanges=TRUE.
	 * @param forceDisjointRanges true to force disjoint ranges.
	 */
	public void setForceDisjointRanges(boolean forceDisjointRanges) {
		this.forceDisjointRanges = forceDisjointRanges;
	}

	@Override
	public void setAsText(String text) throws IllegalArgumentException {

		// split text into ranges
		String[] strRanges = text.split(",");
		Range[] ranges = new Range[strRanges.length];

		// parse ranges and create array of Range objects
		for (int i = 0; i < strRanges.length; i++) {
			String[] range = strRanges[i].split("-");

			int min;
			int max;

			if ((range.length == 1) && (StringUtils.hasText(range[0]))) {
				min = Integer.parseInt(range[0].trim());
				// correct max value will be assigned later
				ranges[i] = new Range(min);
			}
			else if ((range.length == 2) && (StringUtils.hasText(range[0])) && (StringUtils.hasText(range[1]))) {
				min = Integer.parseInt(range[0].trim());
				max = Integer.parseInt(range[1].trim());
				ranges[i] = new Range(min, max);
			}
			else {
				throw new IllegalArgumentException("Range[" + i + "]: range (" + strRanges[i] + ") is invalid");
			}

		}

		setMaxValues(ranges);
		setValue(ranges);
	}

	@Override
	public String getAsText() {
		Range[] ranges = (Range[]) getValue();

		StringBuilder sb = new StringBuilder();

		for (int i = 0; i < ranges.length; i++) {
			if (i > 0) {
				sb.append(", ");
			}
			sb.append(ranges[i]);
		}
		return sb.toString();
	}

	private void setMaxValues(final Range[] ranges) {

		// Array of integers to track range values by index
		Integer[] c = new Integer[ranges.length];
		for (int i = 0; i < c.length; i++) {
			c[i] = i;
		}

		// sort array of Ranges
		Arrays.sort(c, new Comparator<Integer>() {
			@Override
			public int compare(Integer r1, Integer r2) {
				return ranges[r1].getMin() - ranges[r2].getMin();
			}
		});

		// set max values for all unbound ranges (except last range)
		for (int i = 0; i < c.length - 1; i++) {
			if (!ranges[c[i]].hasMaxValue()) {
				// set max value to (min value - 1) of the next range
				ranges[c[i]] = new Range(ranges[c[i]].getMin(), ranges[c[i + 1]].getMin() - 1);
			}
		}

		if (forceDisjointRanges) {
			verifyRanges(ranges);
		}
	}

	private void verifyRanges(Range[] ranges) {
		// verify that ranges are disjoint
		for (int i = 1; i < ranges.length; i++) {
			Assert.isTrue(ranges[i - 1].getMax() < ranges[i].getMin(), "Ranges must be disjoint. Range[" + (i - 1)
					+ "]: (" + ranges[i - 1] + ") Range[" + i + "]: (" + ranges[i] + ")");
		}
	}

}

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