/*
* 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.util;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import org.h2.constant.ErrorCode;
import org.h2.constant.SysProperties;
import org.h2.message.DbException;
/**
* This utility class contains miscellaneous functions.
*/
public class Utils {
/**
* An 0-size byte array.
*/
public static final byte[] EMPTY_BYTES = {};
/**
* An 0-size int array.
*/
public static final int[] EMPTY_INT_ARRAY = {};
/**
* An 0-size long array.
*/
private static final long[] EMPTY_LONG_ARRAY = {};
private static final int GC_DELAY = 50;
private static final int MAX_GC = 8;
private static long lastGC;
private static final HashMap<String, byte[]> RESOURCES = New.hashMap();
private static boolean allowAllClasses;
private static HashSet<String> allowedClassNames;
private static String[] allowedClassNamePrefixes;
private Utils() {
// utility class
}
private static int readInt(byte[] buff, int pos) {
return (buff[pos++] << 24) + ((buff[pos++] & 0xff) << 16) + ((buff[pos++] & 0xff) << 8) + (buff[pos] & 0xff);
}
/**
* Read a long value from the byte array at the given position. The most
* significant byte is read first.
*
* @param buff the byte array
* @param pos the position
* @return the value
*/
public static long readLong(byte[] buff, int pos) {
return ((long) (readInt(buff, pos)) << 32) + (readInt(buff, pos + 4) & 0xffffffffL);
}
/**
* Calculate the index of the first occurrence of the pattern in the byte
* array, starting with the given index. This methods returns -1 if the
* pattern has not been found, and the start position if the pattern is
* empty.
*
* @param bytes the byte array
* @param pattern the pattern
* @param start the start index from where to search
* @return the index
*/
public static int indexOf(byte[] bytes, byte[] pattern, int start) {
if (pattern.length == 0) {
return start;
}
if (start > bytes.length) {
return -1;
}
int last = bytes.length - pattern.length + 1;
int patternLen = pattern.length;
next:
for (; start < last; start++) {
for (int i = 0; i < patternLen; i++) {
if (bytes[start + i] != pattern[i]) {
continue next;
}
}
return start;
}
return -1;
}
/**
* Calculate the hash code of the given byte array.
*
* @param value the byte array
* @return the hash code
*/
public static int getByteArrayHash(byte[] value) {
int len = value.length;
int h = len;
if (len < 50) {
for (int i = 0; i < len; i++) {
h = 31 * h + value[i];
}
} else {
int step = len / 16;
for (int i = 0; i < 4; i++) {
h = 31 * h + value[i];
h = 31 * h + value[--len];
}
for (int i = 4 + step; i < len; i += step) {
h = 31 * h + value[i];
}
}
return h;
}
/**
* Compare two byte arrays. This method will always loop over all bytes and
* doesn't use conditional operations in the loop to make sure an attacker
* can not use a timing attack when trying out passwords.
*
* @param test the first array
* @param good the second array
* @return true if both byte arrays contain the same bytes
*/
public static boolean compareSecure(byte[] test, byte[] good) {
if ((test == null) || (good == null)) {
return (test == null) && (good == null);
}
int len = test.length;
if (len != good.length) {
return false;
}
if (len == 0) {
return true;
}
// don't use conditional operations inside the loop
int bits = 0;
for (int i = 0; i < len; i++) {
// this will never reset any bits
bits |= test[i] ^ good[i];
}
return bits == 0;
}
/**
* Compare the contents of two byte arrays. If the content or length of the
* first array is smaller than the second array, -1 is returned. If the
* content or length of the second array is smaller than the first array, 1
* is returned. If the contents and lengths are the same, 0 is returned.
*
* @param data1 the first byte array (must not be null)
* @param data2 the second byte array (must not be null)
* @return the result of the comparison (-1, 1 or 0)
*/
public static int compareNotNull(byte[] data1, byte[] data2) {
if (data1 == data2) {
return 0;
}
int len = Math.min(data1.length, data2.length);
for (int i = 0; i < len; i++) {
byte b = data1[i];
byte b2 = data2[i];
if (b != b2) {
return b > b2 ? 1 : -1;
}
}
return Integer.signum(data1.length - data2.length);
}
/**
* Copy the contents of the source array to the target array. If the size if
* the target array is too small, a larger array is created.
*
* @param source the source array
* @param target the target array
* @return the target array or a new one if the target array was too small
*/
public static byte[] copy(byte[] source, byte[] target) {
int len = source.length;
if (len > target.length) {
target = new byte[len];
}
System.arraycopy(source, 0, target, 0, len);
return target;
}
/**
* Create a new byte array and copy all the data. If the size of the byte
* array is zero, the same array is returned.
*
* @param b the byte array (may not be null)
* @return a new byte array
*/
public static byte[] cloneByteArray(byte[] b) {
if (b == null) {
return null;
}
int len = b.length;
if (len == 0) {
return b;
}
byte[] copy = new byte[len];
System.arraycopy(b, 0, copy, 0, len);
return copy;
}
/**
* Serialize the object to a byte array.
*
* @param obj the object to serialize
* @return the byte array
*/
public static byte[] serialize(Object obj) {
try {
ByteArrayOutputStream out = new ByteArrayOutputStream();
ObjectOutputStream os = new ObjectOutputStream(out);
os.writeObject(obj);
return out.toByteArray();
} catch (Throwable e) {
throw DbException.get(ErrorCode.SERIALIZATION_FAILED_1, e, e.toString());
}
}
/**
* De-serialize the byte array to an object.
*
* @param data the byte array
* @return the object
* @throws DbException if serialization fails
*/
public static Object deserialize(byte[] data) {
try {
ByteArrayInputStream in = new ByteArrayInputStream(data);
ObjectInputStream is = new ObjectInputStream(in);
return is.readObject();
} catch (Throwable e) {
throw DbException.get(ErrorCode.DESERIALIZATION_FAILED_1, e, e.toString());
}
}
/**
* Calculate the hash code of the given object. The object may be null.
*
* @param o the object
* @return the hash code, or 0 if the object is null
*/
public static int hashCode(Object o) {
return o == null ? 0 : o.hashCode();
}
/**
* Get the used memory in KB.
* This method possibly calls System.gc().
*
* @return the used memory
*/
public static int getMemoryUsed() {
collectGarbage();
Runtime rt = Runtime.getRuntime();
long mem = rt.totalMemory() - rt.freeMemory();
return (int) (mem >> 10);
}
/**
* Get the free memory in KB.
* This method possibly calls System.gc().
*
* @return the free memory
*/
public static int getMemoryFree() {
collectGarbage();
Runtime rt = Runtime.getRuntime();
long mem = rt.freeMemory();
return (int) (mem >> 10);
}
/**
* Get the maximum memory in KB.
*
* @return the maximum memory
*/
public static long getMemoryMax() {
long max = Runtime.getRuntime().maxMemory();
return max / 1024;
}
private static synchronized void collectGarbage() {
Runtime runtime = Runtime.getRuntime();
long total = runtime.totalMemory();
long time = System.currentTimeMillis();
if (lastGC + GC_DELAY < time) {
for (int i = 0; i < MAX_GC; i++) {
runtime.gc();
long now = runtime.totalMemory();
if (now == total) {
lastGC = System.currentTimeMillis();
break;
}
total = now;
}
}
}
/**
* Create an array of bytes with the given size. If this is not possible
* because not enough memory is available, an OutOfMemoryError with the
* requested size in the message is thrown.
*
* @param len the number of bytes requested
* @return the byte array
* @throws OutOfMemoryError
*/
public static byte[] newBytes(int len) {
try {
if (len == 0) {
return EMPTY_BYTES;
}
return new byte[len];
} catch (OutOfMemoryError e) {
Error e2 = new OutOfMemoryError("Requested memory: " + len);
e2.initCause(e);
throw e2;
}
}
/**
* Create an int array with the given size.
*
* @param len the number of bytes requested
* @return the int array
*/
public static int[] newIntArray(int len) {
if (len == 0) {
return EMPTY_INT_ARRAY;
}
return new int[len];
}
/**
* Create a long array with the given size.
*
* @param len the number of bytes requested
* @return the int array
*/
public static long[] newLongArray(int len) {
if (len == 0) {
return EMPTY_LONG_ARRAY;
}
return new long[len];
}
/**
* Load a class, but check if it is allowed to load this class first. To
* perform access rights checking, the system property h2.allowedClasses
* needs to be set to a list of class file name prefixes.
*
* @param className the name of the class
* @return the class object
*/
public static Class<?> loadUserClass(String className) {
if (allowedClassNames == null) {
// initialize the static fields
String s = SysProperties.ALLOWED_CLASSES;
ArrayList<String> prefixes = New.arrayList();
boolean allowAll = false;
HashSet<String> classNames = New.hashSet();
for (String p : StringUtils.arraySplit(s, ',', true)) {
if (p.equals("*")) {
allowAll = true;
} else if (p.endsWith("*")) {
prefixes.add(p.substring(0, p.length() - 1));
} else {
classNames.add(p);
}
}
allowedClassNamePrefixes = new String[prefixes.size()];
prefixes.toArray(allowedClassNamePrefixes);
allowAllClasses = allowAll;
allowedClassNames = classNames;
}
if (!allowAllClasses && !allowedClassNames.contains(className)) {
boolean allowed = false;
for (String s : allowedClassNamePrefixes) {
if (className.startsWith(s)) {
allowed = true;
}
}
if (!allowed) {
throw DbException.get(ErrorCode.ACCESS_DENIED_TO_CLASS_1, className);
}
}
// the following code might be better for OSGi (need to verify):
/*
try {
return Utils.class.getClassLoader().loadClass(className);
} catch (Throwable e) {
try {
return Thread.currentThread().getContextClassLoader().loadClass(className);
} catch (Throwable e2) {
DbException.get(ErrorCode.CLASS_NOT_FOUND_1, e, className);
}
}
*/
try {
return Class.forName(className);
} catch (ClassNotFoundException e) {
try {
return Class.forName(className, true, Thread.currentThread().getContextClassLoader());
} catch (Exception e2) {
throw DbException.get(ErrorCode.CLASS_NOT_FOUND_1, e, className);
}
} catch (NoClassDefFoundError e) {
throw DbException.get(ErrorCode.CLASS_NOT_FOUND_1, e, className);
} catch (Error e) {
// UnsupportedClassVersionError
throw DbException.get(ErrorCode.GENERAL_ERROR_1, e, className);
}
}
/**
* Get a resource from the resource map.
*
* @param name the name of the resource
* @return the resource data
*/
public static byte[] getResource(String name) throws IOException {
byte[] data = RESOURCES.get(name);
if (data == null) {
data = loadResource(name);
RESOURCES.put(name, data);
}
return data == null ? EMPTY_BYTES : data;
}
private static byte[] loadResource(String name) throws IOException {
InputStream in = Utils.class.getResourceAsStream("data.zip");
if (in == null) {
in = Utils.class.getResourceAsStream(name);
if (in == null) {
return null;
}
return IOUtils.readBytesAndClose(in, 0);
}
ZipInputStream zipIn = new ZipInputStream(in);
try {
while (true) {
ZipEntry entry = zipIn.getNextEntry();
if (entry == null) {
break;
}
String entryName = entry.getName();
if (!entryName.startsWith("/")) {
entryName = "/" + entryName;
}
if (entryName.equals(name)) {
ByteArrayOutputStream out = new ByteArrayOutputStream();
IOUtils.copy(zipIn, out);
zipIn.closeEntry();
return out.toByteArray();
}
zipIn.closeEntry();
}
} catch (IOException e) {
// if this happens we have a real problem
e.printStackTrace();
} finally {
zipIn.close();
}
return null;
}
/**
* Calls a static method via reflection. This will try to use the method
* where the most parameter classes match exactly (this algorithm is simpler
* than the one in the Java specification, but works well for most cases).
*
* @param classAndMethod a string with the entire class and method name, eg.
* "java.lang.System.gc"
* @param params the method parameters
* @return the return value from this call
*/
public static Object callStaticMethod(String classAndMethod, Object... params) throws Exception {
int lastDot = classAndMethod.lastIndexOf('.');
String className = classAndMethod.substring(0, lastDot);
String methodName = classAndMethod.substring(lastDot + 1);
return classMethodInternal(methodName, Class.forName(className), null, params);
}
/**
* Calls an instance method via reflection. This will try to use the method
* where the most parameter classes match exactly (this algorithm is simpler
* than the one in the Java specification, but works well for most cases).
*
* @param instance the instance on which the call is done
* @param methodName a string with the method name
* @param params the method parameters
* @return the return value from this call
*/
public static Object callMethod(
Object instance,
String methodName,
Object... params) throws Exception {
return classMethodInternal(methodName, instance.getClass(), instance, params);
}
private static Object classMethodInternal(
String methodName, Class<?> clazz,
Object instance,
Object... params) throws Exception {
Method best = null;
int bestMatch = 0;
boolean isStatic = instance == null;
for (Method m : clazz.getMethods()) {
if (Modifier.isStatic(m.getModifiers()) == isStatic && m.getName().equals(methodName)) {
int p = match(m.getParameterTypes(), params);
if (p > bestMatch) {
bestMatch = p;
best = m;
}
}
}
if (best == null) {
throw new NoSuchMethodException(methodName);
}
return best.invoke(instance, params);
}
/**
* Creates a new instance. This will try to use the constructor where the
* most parameter classes match exactly (this algorithm is simpler than the
* one in the Java specification, but works well for most cases).
*
* @param className a string with the entire class, eg. "java.lang.Integer"
* @param params the constructor parameters
* @return the newly created object
*/
public static Object newInstance(String className, Object... params) throws Exception {
Constructor<?> best = null;
int bestMatch = 0;
for (Constructor<?> c : Class.forName(className).getConstructors()) {
int p = match(c.getParameterTypes(), params);
if (p > bestMatch) {
bestMatch = p;
best = c;
}
}
if (best == null) {
throw new NoSuchMethodException(className);
}
return best.newInstance(params);
}
private static int match(Class<?>[] params, Object[] values) {
int len = params.length;
if (len == values.length) {
int points = 1;
for (int i = 0; i < len; i++) {
Class<?> pc = getNonPrimitiveClass(params[i]);
Class<?> vc = values[i].getClass();
if (pc == vc) {
points++;
} else if (!pc.isAssignableFrom(vc)) {
return 0;
}
}
return points;
}
return 0;
}
/**
* Returns a static field.
*
* @param classAndField a string with the entire class and field name
* @return the field value
*/
public static Object getStaticField(String classAndField) throws Exception {
int lastDot = classAndField.lastIndexOf('.');
String className = classAndField.substring(0, lastDot);
String fieldName = classAndField.substring(lastDot + 1);
return Class.forName(className).getField(fieldName).get(null);
}
/**
* Returns a static field.
*
* @param instance the instance on which the call is done
* @param fieldName the field name
* @return the field value
*/
public static Object getField(Object instance, String fieldName) throws Exception {
return instance.getClass().getField(fieldName).get(instance);
}
/**
* Returns true if the class is present in the current class loader.
*
* @param fullyQualifiedClassName a string with the entire class name, eg.
* "java.lang.System"
* @return true if the class is present
*/
public static boolean isClassPresent(String fullyQualifiedClassName) {
try {
Class.forName(fullyQualifiedClassName);
return true;
} catch (ClassNotFoundException e) {
return false;
}
}
/**
* Convert primitive class names to java.lang.* class names.
*
* @param clazz the class (for example: int)
* @return the non-primitive class (for example: java.lang.Integer)
*/
public static Class<?> getNonPrimitiveClass(Class<?> clazz) {
if (!clazz.isPrimitive()) {
return clazz;
} else if (clazz == boolean.class) {
return Boolean.class;
} else if (clazz == byte.class) {
return Byte.class;
} else if (clazz == char.class) {
return Character.class;
} else if (clazz == double.class) {
return Double.class;
} else if (clazz == float.class) {
return Float.class;
} else if (clazz == int.class) {
return Integer.class;
} else if (clazz == long.class) {
return Long.class;
} else if (clazz == short.class) {
return Short.class;
} else if (clazz == void.class) {
return Void.class;
}
return clazz;
}
/**
* Get the system property. If the system property is not set, or if a
* security exception occurs, the default value is returned.
*
* @param key the key
* @param defaultValue the default value
* @return the value
*/
public static String getProperty(String key, String defaultValue) {
try {
return System.getProperty(key, defaultValue);
} catch (SecurityException se) {
return defaultValue;
}
}
/**
* Get the system property. If the system property is not set, or if a
* security exception occurs, the default value is returned.
*
* @param key the key
* @param defaultValue the default value
* @return the value
*/
public static int getProperty(String key, int defaultValue) {
String s = getProperty(key, null);
if (s != null) {
try {
return Integer.decode(s).intValue();
} catch (NumberFormatException e) {
// ignore
}
}
return defaultValue;
}
/**
* Get the system property. If the system property is not set, or if a
* security exception occurs, the default value is returned.
*
* @param key the key
* @param defaultValue the default value
* @return the value
*/
public static boolean getProperty(String key, boolean defaultValue) {
String s = getProperty(key, null);
if (s != null) {
try {
return Boolean.valueOf(s).booleanValue();
} catch (NumberFormatException e) {
// ignore
}
}
return defaultValue;
}
}