/*
* 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.openjpa.jdbc.kernel.exps;
import java.util.Map;
import org.apache.openjpa.jdbc.meta.ClassMapping;
import org.apache.openjpa.jdbc.meta.FieldMapping;
import org.apache.openjpa.jdbc.schema.Column;
import org.apache.openjpa.jdbc.schema.Table;
import org.apache.openjpa.jdbc.sql.DBDictionary;
import org.apache.openjpa.jdbc.sql.SQLBuffer;
import org.apache.openjpa.jdbc.sql.Select;
import org.apache.openjpa.kernel.exps.ExpressionVisitor;
import org.apache.openjpa.meta.XMLMetaData;
/**
* Test if one string starts with another.
*
* @author Abe White
*/
class StartsWithExpression
implements Exp {
private final Val _val1;
private final Val _val2;
/**
* Constructor. Supply values.
*/
public StartsWithExpression(Val val1, Val val2) {
_val1 = val1;
_val2 = val2;
}
public ExpState initialize(Select sel, ExpContext ctx, Map contains) {
ExpState s1 = _val1.initialize(sel, ctx, 0);
ExpState s2 = _val2.initialize(sel, ctx, 0);
return new BinaryOpExpState(sel.and(s1.joins, s2.joins), s1, s2);
}
public void appendTo(Select sel, ExpContext ctx, ExpState state,
SQLBuffer buf) {
BinaryOpExpState bstate = (BinaryOpExpState) state;
_val1.calculateValue(sel, ctx, bstate.state1, _val2, bstate.state2);
_val2.calculateValue(sel, ctx, bstate.state2, _val1, bstate.state1);
if (_val1 instanceof Const
&& ((Const) _val1).getValue(ctx, bstate.state1) == null)
buf.append("1 <> 1");
else if (_val2 instanceof Const) {
Object o = ((Const) _val2).getValue(ctx, bstate.state2);
if (o == null)
buf.append("1 <> 1");
else {
Column col = null;
if (_val1 instanceof PCPath) {
Column[] cols = ((PCPath) _val1).getColumns(bstate.state1);
if (cols.length == 1)
col = cols[0];
}
_val1.appendTo(sel, ctx, bstate.state1, buf, 0);
buf.append(" LIKE ");
buf.appendValue(o.toString() + "%", col);
}
} else {
String pre = null;
String post = null;
DBDictionary dict = ctx.store.getDBDictionary();
String func = dict.stringLengthFunction;
if (func != null) {
int idx = func.indexOf("{0}");
pre = func.substring(0, idx);
post = func.substring(idx + 3);
}
// if we can't use LIKE, we have to take the substring of the
// first value and compare it to the second
dict.assertSupport(pre != null, "StringLengthFunction");
dict.substring(buf,
new FilterValueImpl(sel, ctx, bstate.state1, _val1),
new ZeroFilterValue(sel, state),
new StringLengthFilterValue(sel, ctx, bstate.state2, pre,post));
buf.append(" = ");
_val2.appendTo(sel, ctx, bstate.state2, buf, 0);
}
sel.append(buf, state.joins);
}
public void selectColumns(Select sel, ExpContext ctx, ExpState state,
boolean pks) {
BinaryOpExpState bstate = (BinaryOpExpState) state;
_val1.selectColumns(sel, ctx, bstate.state1, true);
_val2.selectColumns(sel, ctx, bstate.state2, true);
}
public void acceptVisit(ExpressionVisitor visitor) {
visitor.enter(this);
_val1.acceptVisit(visitor);
_val2.acceptVisit(visitor);
visitor.exit(this);
}
/**
* Evaluates to 0.
*/
private static class ZeroFilterValue
implements FilterValue {
private final Select _sel;
private final ExpState _state;
public ZeroFilterValue(Select sel, ExpState state) {
_sel = sel;
_state = state;
}
public Class getType() {
return int.class;
}
public int length() {
return 1;
}
public void appendTo(SQLBuffer buf) {
appendTo(buf, 0);
}
public void appendTo(SQLBuffer buf, int index) {
buf.appendValue(0);
}
public String getColumnAlias(Column col) {
return _sel.getColumnAlias(col, _state.joins);
}
public String getColumnAlias(String col, Table table) {
return _sel.getColumnAlias(col, table, _state.joins);
}
public Object toDataStoreValue(Object val) {
return val;
}
public boolean isConstant() {
return true;
}
public Object getValue() {
return 0;
}
public Object getSQLValue() {
return 0;
}
public boolean isPath() {
return false;
}
public ClassMapping getClassMapping() {
return null;
}
public FieldMapping getFieldMapping() {
return null;
}
public PCPath getXPath() {
return null;
}
public XMLMetaData getXmlMapping() {
return null;
}
public boolean requiresCast() {
return false;
}
}
/**
* Evaluates to the length of a given value.
*/
private class StringLengthFilterValue
implements FilterValue {
private final Select _sel;
private final ExpContext _ctx;
private final ExpState _state;
private final String _pre;
private final String _post;
public StringLengthFilterValue(Select sel, ExpContext ctx,
ExpState state, String pre, String post){
_sel = sel;
_ctx = ctx;
_state = state;
_pre = pre;
_post = post;
}
public Class getType() {
return int.class;
}
public int length() {
return 1;
}
public void appendTo(SQLBuffer buf) {
appendTo(buf, 0);
}
public void appendTo(SQLBuffer buf, int index) {
buf.append(_pre);
_val2.appendTo(_sel, _ctx, _state, buf, index);
buf.append(_post);
}
public String getColumnAlias(Column col) {
return _sel.getColumnAlias(col, _state.joins);
}
public String getColumnAlias(String col, Table table) {
return _sel.getColumnAlias(col, table, _state.joins);
}
public Object toDataStoreValue(Object val) {
return _val2.toDataStoreValue(_sel, _ctx, _state, val);
}
public boolean isConstant() {
return false;
}
public Object getValue() {
return null;
}
public Object getSQLValue() {
return null;
}
public boolean isPath() {
return false;
}
public ClassMapping getClassMapping() {
return null;
}
public FieldMapping getFieldMapping() {
return null;
}
public PCPath getXPath() {
return null;
}
public XMLMetaData getXmlMapping() {
return null;
}
public boolean requiresCast() {
return false;
}
}
}