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Spring Data Relational support
/*
* Copyright 2019-2022 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.data.relational.core.sql.render;
import org.springframework.data.relational.core.sql.Assignment;
import org.springframework.data.relational.core.sql.Table;
import org.springframework.data.relational.core.sql.Update;
import org.springframework.data.relational.core.sql.Visitable;
import org.springframework.data.relational.core.sql.Where;
/**
* {@link PartRenderer} for {@link Update} statements.
*
* @author Mark Paluch
* @since 1.1
*/
class UpdateStatementVisitor extends DelegatingVisitor implements PartRenderer {
private StringBuilder builder = new StringBuilder();
private StringBuilder table = new StringBuilder();
private StringBuilder assignments = new StringBuilder();
private StringBuilder where = new StringBuilder();
private FromTableVisitor tableVisitor;
private AssignmentVisitor assignmentVisitor;
private WhereClauseVisitor whereClauseVisitor;
UpdateStatementVisitor(RenderContext context) {
this.tableVisitor = new FromTableVisitor(context, it -> {
if (table.length() != 0) {
table.append(", ");
}
table.append(it);
});
this.assignmentVisitor = new AssignmentVisitor(context, it -> {
if (assignments.length() != 0) {
assignments.append(", ");
}
assignments.append(it);
});
this.whereClauseVisitor = new WhereClauseVisitor(context, where::append);
}
/*
* (non-Javadoc)
* @see org.springframework.data.relational.core.sql.render.DelegatingVisitor#doEnter(org.springframework.data.relational.core.sql.Visitable)
*/
@Override
public Delegation doEnter(Visitable segment) {
if (segment instanceof Table) {
return Delegation.delegateTo(this.tableVisitor);
}
if (segment instanceof Assignment) {
return Delegation.delegateTo(this.assignmentVisitor);
}
if (segment instanceof Where) {
return Delegation.delegateTo(this.whereClauseVisitor);
}
return Delegation.retain();
}
/*
* (non-Javadoc)
* @see org.springframework.data.relational.core.sql.render.DelegatingVisitor#doLeave(org.springframework.data.relational.core.sql.Visitable)
*/
@Override
public Delegation doLeave(Visitable segment) {
if (segment instanceof Update) {
builder.append("UPDATE");
if (table.length() != 0) {
builder.append(" ").append(table);
}
if (assignments.length() != 0) {
builder.append(" SET ").append(assignments);
}
if (where.length() != 0) {
builder.append(" WHERE ").append(where);
}
return Delegation.leave();
}
return Delegation.retain();
}
/*
* (non-Javadoc)
* @see org.springframework.data.relational.core.sql.render.PartRenderer#getRenderedPart()
*/
@Override
public CharSequence getRenderedPart() {
return builder;
}
}