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package com.alibaba.simpleEL.dialect.ql;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.reflect.Method;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Map;
import java.util.concurrent.atomic.AtomicLong;
import com.alibaba.simpleEL.ELException;
import com.alibaba.simpleEL.JavaSource;
import com.alibaba.simpleEL.Preprocessor;
import com.alibaba.simpleEL.dialect.ql.ast.QLBetweenExpr;
import com.alibaba.simpleEL.dialect.ql.ast.QLBinaryOpExpr;
import com.alibaba.simpleEL.dialect.ql.ast.QLBinaryOperator;
import com.alibaba.simpleEL.dialect.ql.ast.QLExpr;
import com.alibaba.simpleEL.dialect.ql.ast.QLIdentifierExpr;
import com.alibaba.simpleEL.dialect.ql.ast.QLLimit;
import com.alibaba.simpleEL.dialect.ql.ast.QLOrderBy;
import com.alibaba.simpleEL.dialect.ql.ast.QLOrderByItem;
import com.alibaba.simpleEL.dialect.ql.ast.QLOrderByMode;
import com.alibaba.simpleEL.dialect.ql.ast.QLSelect;
import com.alibaba.simpleEL.dialect.ql.ast.QLVariantRefExpr;
import com.alibaba.simpleEL.dialect.ql.parser.QLSelectParser;
import com.alibaba.simpleEL.dialect.ql.visitor.QLAstVisitor;
import com.alibaba.simpleEL.dialect.ql.visitor.QLAstVisitorAdapter;
import com.alibaba.simpleEL.dialect.ql.visitor.QLOutputAstVisitor;
import com.alibaba.simpleEL.preprocess.TemplatePreProcessor;
public class QLPreprocessor extends TemplatePreProcessor implements Preprocessor {
public static final String ATTR_TYPE = "_TYPE_";
private String packageName = "com.alibaba.simpleEL.dialect.ql.gen";
private final AtomicLong classIdSeed = new AtomicLong(10000L);
private String srcCollectionName = "_src_";
private String destCollectionName = "_dest_";
@Override
public JavaSource handle(Map context, String ql) {
StringWriter writer = new StringWriter();
PrintWriter out = new PrintWriter(writer);
QLSelectParser parser = new QLSelectParser(ql);
QLSelect select = parser.select();
final String className = "GenClass_" + classIdSeed.getAndIncrement();
gen_package(out);
gen_import(out);
gen_class_start(out, className);
gen_eval_start(out);
gen_eval_body(context, select, out);
gen_eval_end(out);
gen_class_end(out);
String text = writer.toString();
return new JavaSource(packageName, className, text);
}
public void gen_package(PrintWriter out) {
out.println("package " + packageName + ";");
out.println();
}
public void gen_import(PrintWriter out) {
out.println("import java.util.*;");
out.println("import static java.lang.Math.*;");
out.println("import com.alibaba.simpleEL.Expr;");
out.println("import static com.alibaba.simpleEL.TypeUtils.*;");
out.println();
}
public void gen_class_start(PrintWriter out, String className) {
out.println("public class " + className + " implements Expr {");
out.println();
}
public void gen_class_end(PrintWriter out) {
out.println();
out.println("}");
}
public void gen_eval_start(PrintWriter out) {
out.println(" public Object eval(Map ctx) {");
}
public void gen_eval_end(PrintWriter out) {
out.println();
out.println(" return null;");
out.println(" }");
}
public void gen_eval_body(Map context, QLSelect select, PrintWriter out) {
Class clazz = (Class) context.get("class");
if (clazz == null) {
throw new IllegalArgumentException("context not contains 'class'");
}
String className = clazz.getName();
className = className.replaceAll("\\$", ".");
String entryVarName = "item";
out.println(" List<" + className + "> " + srcCollectionName + " = (List<" + className
+ ">) ctx.get(\"_src_\");");
out.println(" List<" + className + "> " + destCollectionName + " = (List<" + className
+ ">) ctx.get(\"_dest_\");");
final QLLimit limit = select.getLimit();
if (limit != null) {
if (limit.getOffset() != null) {
out.println(" final int offset = " + limit.getOffset() + ";");
}
out.println(" final int rowCount = " + limit.getRowCount() + ";");
out.println();
if (limit.getOffset() != null) {
out.println(" int rowIndex = 0;");
}
}
out.println(" for (" + className + " " + entryVarName + " : " + srcCollectionName + ") {");
out.println();
gen_where(context, select, out);
out.println();
out.println(" }");
gen_orderBy(context, select, out);
gen_limit(context, select, out);
}
public void gen_limit(final Map context, final QLSelect select, final PrintWriter out) {
QLLimit limit = select.getLimit();
if (limit == null) {
return;
}
out.println();
if (limit.getOffset() != null) {
out.println(" for (int i = 0; i < offset && i < _dest_.size(); ++i) {");
out.println(" _dest_.remove(0);");
out.println(" }");
}
out.println(" while(_dest_.size() > rowCount) {");
out.println(" _dest_.remove(_dest_.size() - 1);");
out.println(" }");
}
public void gen_orderBy(final Map context, final QLSelect select, final PrintWriter out) {
final Class clazz = (Class) context.get("class");
if (clazz == null) {
throw new IllegalArgumentException("context not contains 'class'");
}
final QLOrderBy orderBy = select.getOrderBy();
if (orderBy == null || orderBy.getItems().size() == 0) {
return;
}
String className = clazz.getName();
className = className.replaceAll("\\$", ".");
for (QLOrderByItem item : orderBy.getItems()) {
out.println(" {");
out.println(" Comparator<" + className + "> comparator = new Comparator<" + className + ">() {");
out.println(" public int compare(" + className + " a, " + className + " b) {");
if (item.getMode() == QLOrderByMode.DESC) {
out.println(" if (" + gen_orderByItem(context, "a", item.getExpr()) + " > "
+ gen_orderByItem(context, "b", item.getExpr()) + ") {");
out.println(" return -1;");
out.println(" }");
out.println(" if (" + gen_orderByItem(context, "a", item.getExpr()) + " < "
+ gen_orderByItem(context, "b", item.getExpr()) + ") {");
out.println(" return 1;");
out.println(" }");
} else {
out.println(" if (" + gen_orderByItem(context, "a", item.getExpr()) + " > "
+ gen_orderByItem(context, "b", item.getExpr()) + ") {");
out.println(" return 1;");
out.println(" }");
out.println(" if (" + gen_orderByItem(context, "a", item.getExpr()) + " < "
+ gen_orderByItem(context, "b", item.getExpr()) + ") {");
out.println(" return -1;");
out.println(" }");
}
out.println(" return 0;");
out.println(" }");
out.println(" };");
out.println(" Collections.sort(" + destCollectionName + ", comparator);");
out.println(" }");
}
}
public String gen_orderByItem(final Map context, final String varName, final QLExpr expr) {
final Class clazz = (Class) context.get("class");
if (clazz == null) {
throw new IllegalArgumentException("context not contains 'class'");
}
final StringWriter out = new StringWriter();
QLAstVisitor visitor = new QLOutputAstVisitor(new PrintWriter(out)) {
@Override
public boolean visit(QLIdentifierExpr x) {
String name = x.getName();
Method method = getMethod(clazz, name);
if (method == null) {
throw new ELException("getter not found. " + x.getName());
}
out.print(varName + "." + method.getName() + "()");
return true;
}
};
expr.accept(visitor);
return out.toString();
}
public void gen_where(final Map context, final QLSelect select, final PrintWriter out) {
final Class clazz = (Class) context.get("class");
if (clazz == null) {
throw new IllegalArgumentException("context not contains 'class'");
}
final QLExpr where = select.getWhere();
if (where == null) {
return;
}
final QLLimit limit = select.getLimit();
QLAstVisitorAdapter setTypeVisitor = new SetTypeVisitor(clazz);
where.accept(setTypeVisitor);
out.print(" if(");
QLAstVisitor visitor = new WhereGenOutputVisitor(out, clazz);
where.accept(visitor);
out.println(") {");
if (limit != null && select.getOrderBy() == null) {
out.println(" if (_dest_.size() >= rowCount) {");
out.println(" break;");
out.println(" }");
}
out.println(" " + destCollectionName + ".add(item);");
out.println(" }");
out.println();
}
private static Method getMethod(Class clazz, String name) {
name = name.substring(0, 1).toUpperCase() + name.substring(1);
Method method = null;
try {
method = clazz.getMethod("get" + name);
} catch (NoSuchMethodException e) {
// skip
} catch (Exception e) {
throw new ELException("handle ql where error");
}
if (method == null) {
try {
method = clazz.getMethod("is" + name);
} catch (NoSuchMethodException e) {
// skip
} catch (Exception e) {
throw new ELException("handle ql where error");
}
}
return method;
}
private final class WhereGenOutputVisitor extends QLOutputAstVisitor {
private final Class clazz;
private WhereGenOutputVisitor(PrintWriter out, Class clazz){
super(out);
this.clazz = clazz;
}
@Override
public boolean visit(QLIdentifierExpr x) {
String name = x.getName();
Method method = getMethod(clazz, name);
if (method == null) {
throw new ELException("getter not found. " + x.getName());
}
out.print("item." + method.getName() + "()");
return true;
}
public boolean visit(QLBetweenExpr x) {
if (x.isNot()) {
out.print(" !(");
}
out.print(" _gteq(");
x.getTestExpr().accept(this);
out.print(", ");
x.getBeginExpr().accept(this);
out.print(") && ");
out.print(" _lteq(");
x.getTestExpr().accept(this);
out.print(", ");
x.getEndExpr().accept(this);
out.print(") ");
if (x.isNot()) {
out.print(")");
}
return false;
}
@Override
public boolean visit(QLVariantRefExpr x) {
Class type = (Class) x.getAttributes().get(ATTR_TYPE);
String variant = x.getName();
if (variant.startsWith("@")) {
variant = variant.substring(1);
}
if (type == null) {
type = getVariantResolver().getType(variant);
}
if (type != null) {
if (Boolean.class == type || boolean.class == type) {
out.print("_bool(ctx.get(\"" + variant + "\"))");
} else if (String.class == type) {
out.print("_string(ctx.get(\"" + variant + "\"))");
} else if (Byte.class == type || byte.class == type) {
out.print("_byte(ctx.get(\"" + variant + "\"))");
} else if (Short.class == type || short.class == type) {
out.print("_short(ctx.get(\"" + variant + "\"))");
} else if (Integer.class == type || int.class == type) {
out.print("_int(ctx.get(\"" + variant + "\"))");
} else if (Long.class == type || long.class == type) {
out.print("_long(ctx.get(\"" + variant + "\"))");
} else if (Float.class == type || float.class == type) {
out.print("_float(ctx.get(\"" + variant + "\"))");
} else if (Double.class == type || double.class == type) {
out.print("_double(ctx.get(\"" + variant + "\"))");
} else if (BigInteger.class == type) {
out.print("_bigInt(ctx.get(\"" + variant + "\"))");
} else if (BigDecimal.class == type) {
out.print("_decimal(ctx.get(\"" + variant + "\"))");
} else if (java.util.Date.class == type) {
out.print("_date(ctx.get(\"" + variant + "\"))");
} else if (Object.class == type) {
out.print("ctx.get(\"" + variant + "\")");
} else {
String className = type.getName();
className = className.replaceAll("\\$", "."); // inner
// class
out.print("((" + className + ")" + "ctx.get(\"" + variant + "\"))");
}
} else {
out.print(x.getName());
}
return false;
}
public boolean visit(QLBinaryOpExpr x) {
if (x.getLeft() instanceof QLBinaryOpExpr) {
QLBinaryOpExpr left = (QLBinaryOpExpr) x.getLeft();
if (left.getOperator().priority > x.getOperator().priority) {
out.print('(');
left.accept(this);
out.print(')');
} else {
left.accept(this);
}
} else {
x.getLeft().accept(this);
}
out.print(" ");
if (QLBinaryOperator.BooleanAnd == x.getOperator()) {
out.print("&&");
} else if (QLBinaryOperator.BooleanOr == x.getOperator()) {
out.print("||");
} else {
out.print(x.getOperator().name);
}
out.print(" ");
if (x.getRight() instanceof QLBinaryOpExpr) {
QLBinaryOpExpr right = (QLBinaryOpExpr) x.getRight();
if (right.getOperator().priority >= x.getOperator().priority) {
out.print('(');
right.accept(this);
out.print(')');
} else {
right.accept(this);
}
} else {
x.getRight().accept(this);
}
return false;
}
}
private final class SetTypeVisitor extends QLAstVisitorAdapter {
private final Class clazz;
private SetTypeVisitor(Class clazz){
this.clazz = clazz;
}
@Override
public boolean visit(QLIdentifierExpr x) {
String name = x.getName();
Method method = getMethod(clazz, name);
if (method == null) {
throw new ELException("getter not found. " + x.getName());
}
x.getAttributes().put(ATTR_TYPE, method.getReturnType());
return false;
}
@Override
public boolean visit(QLBinaryOpExpr x) {
x.getLeft().accept(this);
x.getRight().accept(this);
Class leftType = (Class) x.getLeft().getAttributes().get(ATTR_TYPE);
Class rightType = (Class) x.getRight().getAttributes().get(ATTR_TYPE);
if (leftType == null && rightType != null) {
x.getLeft().getAttributes().put(ATTR_TYPE, rightType);
}
if (rightType == null && leftType != null) {
x.getRight().getAttributes().put(ATTR_TYPE, leftType);
}
return false;
}
}
}
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