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JdbcMapper
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Code Issues Releases Wiki Activity

Optimize InListUtil.java

This commit is contained in:
Travis Burtrum 2018-05-23 00:50:12 -04:00
parent 3f45785865
commit 9c1efdc715
2 changed files with 68 additions and 54 deletions
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116
common/src/main/java/com/moparisthebest/jdbc/util/InListUtil.java
View File

@ -1,86 +1,98 @@
package com.moparisthebest.jdbc.util;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.*;
public class InListUtil {
public static final int defaultMaxSize = Integer.parseInt(System.getProperty("QueryMapper.BindInList.defaultMaxSize", "999"));
public static final String inEmpty = "(0=1)", notInEmpty = "(1=1)";
private static <T> List<List<T>> split(final List<T> list, final int maxLength) {
final int listSize = list.size();
final List<List<T>> ret = new ArrayList<List<T>>();
if (listSize < maxLength)
ret.add(list);
else
for (int fromIndex = 0, toIndex = maxLength; fromIndex < listSize; fromIndex = toIndex, toIndex += maxLength)
ret.add(list.subList(fromIndex, toIndex > listSize ? listSize : toIndex));
return ret;
}
// fieldName + listPrefix + 3 parens + ((number expected which is less than maxSize * 2) - 1) assuming 20 items = 39 + 3 = 42
public static final int defaultInListPreallocLength = Integer.parseInt(System.getProperty("QueryMapper.BindInList.defaultInListPreallocLength", "42"));
private static <T> StringBuilder buildCommaSeparatedList(final Iterable<T> list, final StringBuilder sb) {
boolean notFirst = false;
for (final T obj : list) {
if (notFirst) sb.append(',');
else notFirst = true;
sb.append('?');
}
return sb;
}
private static <T> StringBuilder buildInList(final Iterable<T> list, final StringBuilder sb, final String fieldName, final String listPrefix) {
return buildCommaSeparatedList(list, sb.append(fieldName).append(listPrefix)).append(")");
}
private static <T> String toInList(final String fieldName, final Collection<T> items, final int maxSize, final String listPrefix, final String listCombine) {
final StringBuilder sb = new StringBuilder("(");
// do it quick if it will fit in one in-list
if (items.size() < maxSize) // 999 or less
return buildInList(items, sb, fieldName, listPrefix).append(")").toString();
private static <T> String toNotInListNonEmpty(final String fieldName, final Iterator<T> items, final int maxSize, final String listPrefix, final String listCombine) {
final StringBuilder sb = new StringBuilder(fieldName.length() + listPrefix.length() + defaultInListPreallocLength);
sb.append('(');
// else we need to split lists
boolean notFirst = false;
for (final List<T> item : split(items instanceof List ? (List<T>) items : new ArrayList<T>(items), maxSize)) {
if (notFirst) sb.append(listCombine);
else notFirst = true;
buildInList(item, sb, fieldName, listPrefix);
int count;
while(true) {
sb.append(fieldName).append(listPrefix);
count = 1;
while(true) {
items.next();
sb.append('?');
if (!items.hasNext() || ++count > maxSize)
break;
sb.append(',');
}
sb.append(')');
if(!items.hasNext())
break;
sb.append(listCombine);
}
return sb.append(")").toString();
return sb.append(')').toString();
}
private static <T> String toInListNonEmpty(final String fieldName, final Collection<T> items, final int maxSize) {
return toInList(fieldName, items, maxSize, " IN (", " OR ");
private static <T> String toInListNonEmpty(final String fieldName, final Iterator<T> items, final int maxSize) {
return toNotInListNonEmpty(fieldName, items, maxSize, " IN (", " OR ");
}
private static <T> String toNotInListNonEmpty(final String fieldName, final Collection<T> items, final int maxSize) {
return toInList(fieldName, items, maxSize, " NOT IN (", " AND ");
private static <T> String toNotInListNonEmpty(final String fieldName, final Iterator<T> items, final int maxSize) {
return toNotInListNonEmpty(fieldName, items, maxSize, " NOT IN (", " AND ");
}
public static <T> String toInList(final String fieldName, final Collection<T> items, final int maxSize) {
return items == null || items.isEmpty() ? "(0=1)" : toInListNonEmpty(fieldName, items, maxSize);
public static <T> String toInList(final String fieldName, final Iterator<T> items, final int maxSize) {
return items == null || !items.hasNext() ? inEmpty : toInListNonEmpty(fieldName, items, maxSize);
}
public static <T> String toNotInList(final String fieldName, final Collection<T> items, final int maxSize) {
return items == null || items.isEmpty() ? "(1=1)" : toNotInListNonEmpty(fieldName, items, maxSize);
public static <T> String toNotInList(final String fieldName, final Iterator<T> items, final int maxSize) {
return items == null || !items.hasNext() ? notInEmpty : toNotInListNonEmpty(fieldName, items, maxSize);
}
public static <T> String toInList(final String fieldName, final Collection<T> items) {
public static <T> String toInList(final String fieldName, final Iterable<T> items, final int maxSize) {
final Iterator<T> itemIt;
return items == null || !(itemIt = items.iterator()).hasNext() ? inEmpty : toInListNonEmpty(fieldName, itemIt, maxSize);
}
public static <T> String toNotInList(final String fieldName, final Iterable<T> items, final int maxSize) {
final Iterator<T> itemIt;
return items == null || !(itemIt = items.iterator()).hasNext() ? notInEmpty : toNotInListNonEmpty(fieldName, itemIt, maxSize);
}
public static <T> String toInList(final String fieldName, final T[] items, final int maxSize) {
// is Arrays.asList(items).iterator() the best iterator for Array ? why aren't they Iterable again...
return items == null || items.length == 0 ? inEmpty : toInListNonEmpty(fieldName, Arrays.asList(items).iterator(), maxSize);
}
public static <T> String toNotInList(final String fieldName, final T[] items, final int maxSize) {
return items == null || items.length == 0 ? notInEmpty : toNotInListNonEmpty(fieldName, Arrays.asList(items).iterator(), maxSize);
}
public static <T> String toInList(final String fieldName, final Iterator<T> items) {
return toInList(fieldName, items, defaultMaxSize);
}
public static <T> String toNotInList(final String fieldName, final Collection<T> items) {
public static <T> String toNotInList(final String fieldName, final Iterator<T> items) {
return toNotInList(fieldName, items, defaultMaxSize);
}
public static <T> String toInList(final String fieldName, final Iterable<T> items) {
return toInList(fieldName, items, defaultMaxSize);
}
public static <T> String toNotInList(final String fieldName, final Iterable<T> items) {
return toNotInList(fieldName, items, defaultMaxSize);
}
public static <T> String toInList(final String fieldName, final T[] items) {
return toInList(fieldName, Arrays.asList(items), defaultMaxSize);
return toInList(fieldName, items, defaultMaxSize);
}
public static <T> String toNotInList(final String fieldName, final T[] items) {
return toNotInList(fieldName, Arrays.asList(items), defaultMaxSize);
return toNotInList(fieldName, items, defaultMaxSize);
}
}

6
querymapper/src/main/java/com/moparisthebest/jdbc/InList.java
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@ -1,5 +1,7 @@
package com.moparisthebest.jdbc;
import com.moparisthebest.jdbc.util.InListUtil;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Collection;
@ -27,8 +29,8 @@ public interface InList {
public <T> InListObject notInList(final Connection conn, final String columnName, final Collection<T> values) throws SQLException;
class InListObject {
static final InListObject inEmpty = new InListObject("(0=1)");
static final InListObject notInEmpty = new InListObject("(1=1)");
static final InListObject inEmpty = new InListObject(InListUtil.inEmpty);
static final InListObject notInEmpty = new InListObject(InListUtil.notInEmpty);
private final String sql;