com.querydsl.sql.WindowFunction Maven / Gradle / Ivy
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/*
* Copyright 2015, The Querydsl Team (http://www.querydsl.com/team)
*
* 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
* 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 com.querydsl.sql;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.jetbrains.annotations.Nullable;
import com.querydsl.core.types.*;
import com.querydsl.core.types.dsl.BooleanExpression;
import com.querydsl.core.types.dsl.ComparableExpressionBase;
import com.querydsl.core.types.dsl.Expressions;
import com.querydsl.core.types.dsl.SimpleExpression;
/**
* {@code WindowFunction} is a builder for window function expressions
*
* @param expression type
*
* @author tiwe
*/
public class WindowFunction extends MutableExpressionBase {
private static final String ORDER_BY = "order by ";
private static final String PARTITION_BY = "partition by ";
private static final long serialVersionUID = -4130672293308756779L;
private final List> orderBy = new ArrayList>();
private final List> partitionBy = new ArrayList>();
private final Expression target;
@Nullable
private transient volatile SimpleExpression value;
private String rowsOrRange;
private List> rowsOrRangeArgs;
public WindowFunction(Expression expr) {
super(expr.getType());
this.target = expr;
}
public SimpleExpression getValue() {
if (value == null) {
int size = 0;
List> args = new ArrayList<>();
StringBuilder builder = new StringBuilder();
builder.append("{0} over (");
args.add(target);
size++;
if (!partitionBy.isEmpty()) {
builder.append(PARTITION_BY);
boolean first = true;
for (Expression expr : partitionBy) {
if (!first) {
builder.append(", ");
}
builder.append("{").append(size).append("}");
args.add(expr);
size++;
first = false;
}
}
if (!orderBy.isEmpty()) {
if (!partitionBy.isEmpty()) {
builder.append(" ");
}
builder.append(ORDER_BY);
builder.append("{").append(size).append("}");
args.add(ExpressionUtils.orderBy(orderBy));
size++;
}
if (rowsOrRange != null) {
builder.append(rowsOrRange);
args.addAll(rowsOrRangeArgs);
size += rowsOrRangeArgs.size();
}
builder.append(")");
value = Expressions.template(target.getType(), builder.toString(), Collections.unmodifiableList(args));
}
return value;
}
@SuppressWarnings("unchecked")
public SimpleExpression as(Expression alias) {
return Expressions.operation(getType(), Ops.ALIAS, this, alias);
}
public SimpleExpression as(String alias) {
return Expressions.operation(getType(), Ops.ALIAS, this, ExpressionUtils.path(getType(), alias));
}
@Override
public R accept(Visitor v, C context) {
return getValue().accept(v, context);
}
@Override
public boolean equals(Object o) {
if (o == this) {
return true;
} else if (o instanceof WindowFunction) {
WindowFunction so = (WindowFunction) o;
return so.target.equals(target)
&& so.partitionBy.equals(partitionBy)
&& so.orderBy.equals(orderBy);
} else {
return false;
}
}
public BooleanExpression eq(Expression expr) {
return getValue().eq(expr);
}
public BooleanExpression eq(A arg) {
return getValue().eq(arg);
}
public BooleanExpression ne(Expression expr) {
return getValue().ne(expr);
}
public BooleanExpression ne(A arg) {
return getValue().ne(arg);
}
public WindowFunction orderBy(ComparableExpressionBase orderBy) {
value = null;
this.orderBy.add(orderBy.asc());
return this;
}
public WindowFunction orderBy(ComparableExpressionBase... orderBy) {
value = null;
for (ComparableExpressionBase e : orderBy) {
this.orderBy.add(e.asc());
}
return this;
}
public WindowFunction orderBy(OrderSpecifier orderBy) {
value = null;
this.orderBy.add(orderBy);
return this;
}
public WindowFunction orderBy(OrderSpecifier... orderBy) {
value = null;
Collections.addAll(this.orderBy, orderBy);
return this;
}
public WindowFunction partitionBy(Expression partitionBy) {
value = null;
this.partitionBy.add(partitionBy);
return this;
}
public WindowFunction partitionBy(Expression... partitionBy) {
value = null;
Collections.addAll(this.partitionBy, partitionBy);
return this;
}
WindowFunction withRowsOrRange(String s, List> args) {
rowsOrRange = s;
rowsOrRangeArgs = args;
return this;
}
public WindowRows rows() {
value = null;
int offset = orderBy.size() + partitionBy.size() + 1;
return new WindowRows(this, " rows", offset);
}
public WindowRows range() {
value = null;
int offset = orderBy.size() + partitionBy.size() + 1;
return new WindowRows(this, " range", offset);
}
}