/*
* Copyright 2004-2011 H2 Group. Multiple-Licensed under the H2 License,
* Version 1.0, and under the Eclipse Public License, Version 1.0
* (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.engine;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.sql.Connection;
import java.util.ArrayList;
import java.util.Arrays;
import org.h2.Driver;
import org.h2.command.Parser;
import org.h2.constant.ErrorCode;
import org.h2.constant.SysProperties;
import org.h2.expression.Expression;
import org.h2.message.DbException;
import org.h2.message.Trace;
import org.h2.schema.Schema;
import org.h2.schema.SchemaObjectBase;
import org.h2.table.Table;
import org.h2.util.New;
import org.h2.util.SourceCompiler;
import org.h2.util.StatementBuilder;
import org.h2.util.StringUtils;
import org.h2.util.Utils;
import org.h2.value.DataType;
import org.h2.value.Value;
import org.h2.value.ValueArray;
import org.h2.value.ValueNull;
/**
* Represents a user-defined function, or alias.
*
* @author Thomas Mueller
* @author Gary Tong
*/
public class FunctionAlias extends SchemaObjectBase {
private String className;
private String methodName;
private String source;
private JavaMethod[] javaMethods;
private boolean deterministic;
private FunctionAlias(Schema schema, int id, String name) {
initSchemaObjectBase(schema, id, name, Trace.FUNCTION);
}
/**
* Create a new alias based on a method name.
*
* @param schema the schema
* @param id the id
* @param name the name
* @param javaClassMethod the class and method name
* @param force create the object even if the class or method does not exist
* @return the database object
*/
public static FunctionAlias newInstance(Schema schema, int id, String name, String javaClassMethod, boolean force) {
FunctionAlias alias = new FunctionAlias(schema, id, name);
int paren = javaClassMethod.indexOf('(');
int lastDot = javaClassMethod.lastIndexOf('.', paren < 0 ? javaClassMethod.length() : paren);
if (lastDot < 0) {
throw DbException.get(ErrorCode.SYNTAX_ERROR_1, javaClassMethod);
}
alias.className = javaClassMethod.substring(0, lastDot);
alias.methodName = javaClassMethod.substring(lastDot + 1);
alias.init(force);
return alias;
}
/**
* Create a new alias based on source code.
*
* @param schema the schema
* @param id the id
* @param name the name
* @param source the source code
* @param force create the object even if the class or method does not exist
* @return the database object
*/
public static FunctionAlias newInstanceFromSource(Schema schema, int id, String name, String source, boolean force) {
FunctionAlias alias = new FunctionAlias(schema, id, name);
alias.source = source;
alias.init(force);
return alias;
}
private void init(boolean force) {
try {
// at least try to compile the class, otherwise the data type is not
// initialized if it could be
load();
} catch (DbException e) {
if (!force) {
throw e;
}
}
}
private synchronized void load() {
if (javaMethods != null) {
return;
}
if (source != null) {
loadFromSource();
} else {
loadClass();
}
}
private void loadFromSource() {
SourceCompiler compiler = database.getCompiler();
synchronized (compiler) {
String fullClassName = Constants.USER_PACKAGE + "." + getName();
compiler.setSource(fullClassName, source);
try {
Method m = compiler.getMethod(fullClassName);
JavaMethod method = new JavaMethod(m, 0);
javaMethods = new JavaMethod[] {
method
};
} catch (DbException e) {
throw e;
} catch (Exception e) {
throw DbException.get(ErrorCode.SYNTAX_ERROR_1, e, source);
}
}
}
private void loadClass() {
Class<?> javaClass = Utils.loadUserClass(className);
Method[] methods = javaClass.getMethods();
ArrayList<JavaMethod> list = New.arrayList();
for (int i = 0, len = methods.length; i < len; i++) {
Method m = methods[i];
if (!Modifier.isStatic(m.getModifiers())) {
continue;
}
if (m.getName().equals(methodName) || getMethodSignature(m).equals(methodName)) {
JavaMethod javaMethod = new JavaMethod(m, i);
for (JavaMethod old : list) {
if (old.getParameterCount() == javaMethod.getParameterCount()) {
throw DbException.get(
ErrorCode.METHODS_MUST_HAVE_DIFFERENT_PARAMETER_COUNTS_2,
old.toString(), javaMethod.toString()
);
}
}
list.add(javaMethod);
}
}
if (list.size() == 0) {
throw DbException.get(ErrorCode.PUBLIC_STATIC_JAVA_METHOD_NOT_FOUND_1, methodName + " (" + className + ")");
}
javaMethods = new JavaMethod[list.size()];
list.toArray(javaMethods);
// Sort elements. Methods with a variable number of arguments must be at
// the end. Reason: there could be one method without parameters and one
// with a variable number. The one without parameters needs to be used
// if no parameters are given.
Arrays.sort(javaMethods);
}
private static String getMethodSignature(Method m) {
StatementBuilder buff = new StatementBuilder(m.getName());
buff.append('(');
for (Class<?> p : m.getParameterTypes()) {
// do not use a space here, because spaces are removed
// in CreateFunctionAlias.setJavaClassMethod()
buff.appendExceptFirst(",");
if (p.isArray()) {
buff.append(p.getComponentType().getName()).append("[]");
} else {
buff.append(p.getName());
}
}
return buff.append(')').toString();
}
public String getCreateSQLForCopy(Table table, String quotedName) {
throw DbException.throwInternalError();
}
public String getDropSQL() {
return "DROP ALIAS IF EXISTS " + getSQL();
}
public String getSQL() {
// TODO can remove this method once FUNCTIONS_IN_SCHEMA is enabled
if (database.getSettings().functionsInSchema || !getSchema().getName().equals(Constants.SCHEMA_MAIN)) {
return super.getSQL();
}
return Parser.quoteIdentifier(getName());
}
public String getCreateSQL() {
StringBuilder buff = new StringBuilder("CREATE FORCE ALIAS ");
buff.append(getSQL());
if (deterministic) {
buff.append(" DETERMINISTIC");
}
if (source != null) {
buff.append(" AS ").append(StringUtils.quoteStringSQL(source));
} else {
buff.append(" FOR ").append(Parser.quoteIdentifier(className + "." + methodName));
}
return buff.toString();
}
public int getType() {
return DbObject.FUNCTION_ALIAS;
}
public synchronized void removeChildrenAndResources(Session session) {
database.removeMeta(session, getId());
className = null;
methodName = null;
javaMethods = null;
invalidate();
}
public void checkRename() {
throw DbException.getUnsupportedException("RENAME");
}
/**
* Find the Java method that matches the arguments.
*
* @param args the argument list
* @return the Java method
* @throws DbException if no matching method could be found
*/
public JavaMethod findJavaMethod(Expression[] args) {
load();
int parameterCount = args.length;
for (JavaMethod m : javaMethods) {
int count = m.getParameterCount();
if (count == parameterCount || (m.isVarArgs() && count <= parameterCount + 1)) {
return m;
}
}
throw DbException.get(ErrorCode.METHOD_NOT_FOUND_1,
methodName + " (" + className + ", parameter count: " + parameterCount + ")");
}
public String getJavaClassName() {
return this.className;
}
public String getJavaMethodName() {
return this.methodName;
}
/**
* Get the Java methods mapped by this function.
*
* @return the Java methods.
*/
public JavaMethod[] getJavaMethods() {
load();
return javaMethods;
}
/**
* There may be multiple Java methods that match a function name.
* Each method must have a different number of parameters however.
* This helper class represents one such method.
*/
public static class JavaMethod implements Comparable<JavaMethod> {
private final int id;
private final Method method;
private final int dataType;
private boolean hasConnectionParam;
private boolean varArgs;
private Class<?> varArgClass;
private int paramCount;
JavaMethod(Method method, int id) {
this.method = method;
this.id = id;
Class<?>[] paramClasses = method.getParameterTypes();
paramCount = paramClasses.length;
if (paramCount > 0) {
Class<?> paramClass = paramClasses[0];
if (Connection.class.isAssignableFrom(paramClass)) {
hasConnectionParam = true;
paramCount--;
}
}
if (paramCount > 0) {
Class<?> lastArg = paramClasses[paramClasses.length - 1];
if (lastArg.isArray() && FunctionAlias.isVarArgs(method)) {
varArgs = true;
varArgClass = lastArg.getComponentType();
}
}
Class<?> returnClass = method.getReturnType();
dataType = DataType.getTypeFromClass(returnClass);
}
public String toString() {
return method.toString();
}
/**
* Check if this function requires a database connection.
*
* @return if the function requires a connection
*/
public boolean hasConnectionParam() {
return this.hasConnectionParam;
}
/**
* Call the user-defined function and return the value.
*
* @param session the session
* @param args the argument list
* @param columnList true if the function should only return the column list
* @return the value
*/
public Value getValue(Session session, Expression[] args, boolean columnList) {
Class<?>[] paramClasses = method.getParameterTypes();
Object[] params = new Object[paramClasses.length];
int p = 0;
if (hasConnectionParam && params.length > 0) {
params[p++] = session.createConnection(columnList);
}
// allocate array for varArgs parameters
Object varArg = null;
if (varArgs) {
int len = args.length - params.length + 1 + (hasConnectionParam ? 1 : 0);
varArg = Array.newInstance(varArgClass, len);
params[params.length - 1] = varArg;
}
for (int a = 0, len = args.length; a < len; a++, p++) {
boolean currentIsVarArg = varArgs && p >= paramClasses.length - 1;
Class<?> paramClass;
if (currentIsVarArg) {
paramClass = varArgClass;
} else {
paramClass = paramClasses[p];
}
int type = DataType.getTypeFromClass(paramClass);
Value v = args[a].getValue(session);
Object o;
if (Value.class.isAssignableFrom(paramClass)) {
o = v;
} else if (v.getType() == Value.ARRAY && paramClass.isArray() && paramClass.getComponentType() != Object.class) {
Value[] array = ((ValueArray) v).getList();
Object[] objArray = (Object[]) Array.newInstance(paramClass.getComponentType(), array.length);
int componentType = DataType.getTypeFromClass(paramClass.getComponentType());
for (int i = 0; i < objArray.length; i++) {
objArray[i] = array[i].convertTo(componentType).getObject();
}
o = objArray;
} else {
v = v.convertTo(type);
o = v.getObject();
}
if (o == null) {
if (paramClass.isPrimitive()) {
if (columnList) {
// if the column list is requested, the parameters may
// be null
// need to set to default value,
// otherwise the function can't be called at all
o = DataType.getDefaultForPrimitiveType(paramClass);
} else {
// NULL for a java primitive: return NULL
return ValueNull.INSTANCE;
}
}
} else {
if (!paramClass.isAssignableFrom(o.getClass()) && !paramClass.isPrimitive()) {
o = DataType.convertTo(session, session.createConnection(false), v, paramClass);
}
}
if (currentIsVarArg) {
Array.set(varArg, p - params.length + 1, o);
} else {
params[p] = o;
}
}
boolean old = session.getAutoCommit();
Value identity = session.getScopeIdentity();
boolean defaultConnection = session.getDatabase().getSettings().defaultConnection;
try {
session.setAutoCommit(false);
Object returnValue;
try {
if (defaultConnection) {
Driver.setDefaultConnection(session.createConnection(columnList));
}
returnValue = method.invoke(null, params);
if (returnValue == null) {
return ValueNull.INSTANCE;
}
} catch (InvocationTargetException e) {
StatementBuilder buff = new StatementBuilder(method.getName());
buff.append('(');
for (Object o : params) {
buff.appendExceptFirst(", ");
buff.append(o == null ? "null" : o.toString());
}
buff.append(')');
throw DbException.convertInvocation(e, buff.toString());
} catch (Exception e) {
throw DbException.convert(e);
}
if (Value.class.isAssignableFrom(method.getReturnType())) {
return (Value) returnValue;
}
Value ret = DataType.convertToValue(session, returnValue, dataType);
return ret.convertTo(dataType);
} finally {
session.setScopeIdentity(identity);
session.setAutoCommit(old);
if (defaultConnection) {
Driver.setDefaultConnection(null);
}
}
}
public Class<?>[] getColumnClasses() {
return method.getParameterTypes();
}
public int getDataType() {
return dataType;
}
public int getParameterCount() {
return paramCount;
}
public boolean isVarArgs() {
return varArgs;
}
public int compareTo(JavaMethod m) {
if (varArgs != m.varArgs) {
return varArgs ? 1 : -1;
}
if (paramCount != m.paramCount) {
return paramCount - m.paramCount;
}
if (hasConnectionParam != m.hasConnectionParam) {
return hasConnectionParam ? 1 : -1;
}
return id - m.id;
}
}
public void setDeterministic(boolean deterministic) {
this.deterministic = deterministic;
}
public boolean isDeterministic() {
return deterministic;
}
public String getSource() {
return source;
}
/**
* Checks if the given method takes a variable number of arguments. For Java
* 1.4 and older, false is returned. Example:
* <pre>
* public static double mean(double... values)
* </pre>
*
* @param m the method to test
* @return true if the method takes a variable number of arguments.
*/
static boolean isVarArgs(Method m) {
if ("1.5".compareTo(SysProperties.JAVA_SPECIFICATION_VERSION) > 0) {
return false;
}
try {
Method isVarArgs = m.getClass().getMethod("isVarArgs");
Boolean result = (Boolean) isVarArgs.invoke(m);
return result.booleanValue();
} catch (Exception e) {
return false;
}
}
}