Java tutorial
/* * Copyright (C) 2006 The Android Open Source Project * * 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 * * 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 android.database.sqlite; import android.annotation.UnsupportedAppUsage; import android.database.DatabaseUtils; import android.os.CancellationSignal; import java.util.Arrays; /** * A base class for compiled SQLite programs. * <p> * This class is not thread-safe. * </p> */ public abstract class SQLiteProgram extends SQLiteClosable { private static final String[] EMPTY_STRING_ARRAY = new String[0]; private final SQLiteDatabase mDatabase; @UnsupportedAppUsage private final String mSql; private final boolean mReadOnly; private final String[] mColumnNames; private final int mNumParameters; @UnsupportedAppUsage private final Object[] mBindArgs; SQLiteProgram(SQLiteDatabase db, String sql, Object[] bindArgs, CancellationSignal cancellationSignalForPrepare) { mDatabase = db; mSql = sql.trim(); int n = DatabaseUtils.getSqlStatementType(mSql); switch (n) { case DatabaseUtils.STATEMENT_BEGIN: case DatabaseUtils.STATEMENT_COMMIT: case DatabaseUtils.STATEMENT_ABORT: mReadOnly = false; mColumnNames = EMPTY_STRING_ARRAY; mNumParameters = 0; break; default: boolean assumeReadOnly = (n == DatabaseUtils.STATEMENT_SELECT); SQLiteStatementInfo info = new SQLiteStatementInfo(); db.getThreadSession().prepare(mSql, db.getThreadDefaultConnectionFlags(assumeReadOnly), cancellationSignalForPrepare, info); mReadOnly = info.readOnly; mColumnNames = info.columnNames; mNumParameters = info.numParameters; break; } if (bindArgs != null && bindArgs.length > mNumParameters) { throw new IllegalArgumentException("Too many bind arguments. " + bindArgs.length + " arguments were provided but the statement needs " + mNumParameters + " arguments."); } if (mNumParameters != 0) { mBindArgs = new Object[mNumParameters]; if (bindArgs != null) { System.arraycopy(bindArgs, 0, mBindArgs, 0, bindArgs.length); } } else { mBindArgs = null; } } final SQLiteDatabase getDatabase() { return mDatabase; } final String getSql() { return mSql; } final Object[] getBindArgs() { return mBindArgs; } final String[] getColumnNames() { return mColumnNames; } /** @hide */ protected final SQLiteSession getSession() { return mDatabase.getThreadSession(); } /** @hide */ protected final int getConnectionFlags() { return mDatabase.getThreadDefaultConnectionFlags(mReadOnly); } /** @hide */ protected final void onCorruption() { mDatabase.onCorruption(); } /** * Unimplemented. * @deprecated This method is deprecated and must not be used. */ @Deprecated public final int getUniqueId() { return -1; } /** * Bind a NULL value to this statement. The value remains bound until * {@link #clearBindings} is called. * * @param index The 1-based index to the parameter to bind null to */ public void bindNull(int index) { bind(index, null); } /** * Bind a long value to this statement. The value remains bound until * {@link #clearBindings} is called. *addToBindArgs * @param index The 1-based index to the parameter to bind * @param value The value to bind */ public void bindLong(int index, long value) { bind(index, value); } /** * Bind a double value to this statement. The value remains bound until * {@link #clearBindings} is called. * * @param index The 1-based index to the parameter to bind * @param value The value to bind */ public void bindDouble(int index, double value) { bind(index, value); } /** * Bind a String value to this statement. The value remains bound until * {@link #clearBindings} is called. * * @param index The 1-based index to the parameter to bind * @param value The value to bind, must not be null */ public void bindString(int index, String value) { if (value == null) { throw new IllegalArgumentException("the bind value at index " + index + " is null"); } bind(index, value); } /** * Bind a byte array value to this statement. The value remains bound until * {@link #clearBindings} is called. * * @param index The 1-based index to the parameter to bind * @param value The value to bind, must not be null */ public void bindBlob(int index, byte[] value) { if (value == null) { throw new IllegalArgumentException("the bind value at index " + index + " is null"); } bind(index, value); } /** * Clears all existing bindings. Unset bindings are treated as NULL. */ public void clearBindings() { if (mBindArgs != null) { Arrays.fill(mBindArgs, null); } } /** * Given an array of String bindArgs, this method binds all of them in one single call. * * @param bindArgs the String array of bind args, none of which must be null. */ public void bindAllArgsAsStrings(String[] bindArgs) { if (bindArgs != null) { for (int i = bindArgs.length; i != 0; i--) { bindString(i, bindArgs[i - 1]); } } } @Override protected void onAllReferencesReleased() { clearBindings(); } private void bind(int index, Object value) { if (index < 1 || index > mNumParameters) { throw new IllegalArgumentException( "Cannot bind argument at index " + index + " because the index is out of range. " + "The statement has " + mNumParameters + " parameters."); } mBindArgs[index - 1] = value; } }