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/*
* 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;
/**
* A base class for Cursors that store their data in {@link CursorWindow}s.
* <p>
* The cursor owns the cursor window it uses. When the cursor is closed,
* its window is also closed. Likewise, when the window used by the cursor is
* changed, its old window is closed. This policy of strict ownership ensures
* that cursor windows are not leaked.
* </p><p>
* Subclasses are responsible for filling the cursor window with data during
* {@link #onMove(int, int)}, allocating a new cursor window if necessary.
* During {@link #requery()}, the existing cursor window should be cleared and
* filled with new data.
* </p><p>
* If the contents of the cursor change or become invalid, the old window must be closed
* (because it is owned by the cursor) and set to null.
* </p>
*/
public abstract class AbstractWindowedCursor extends AbstractCursor {
/**
* The cursor window owned by this cursor.
*/
protected CursorWindow mWindow;
@Override
public byte[] getBlob(int columnIndex) {
checkPosition();
return mWindow.getBlob(mPos, columnIndex);
}
@Override
public String getString(int columnIndex) {
checkPosition();
return mWindow.getString(mPos, columnIndex);
}
@Override
public void copyStringToBuffer(int columnIndex, CharArrayBuffer buffer) {
checkPosition();
mWindow.copyStringToBuffer(mPos, columnIndex, buffer);
}
@Override
public short getShort(int columnIndex) {
checkPosition();
return mWindow.getShort(mPos, columnIndex);
}
@Override
public int getInt(int columnIndex) {
checkPosition();
return mWindow.getInt(mPos, columnIndex);
}
@Override
public long getLong(int columnIndex) {
checkPosition();
return mWindow.getLong(mPos, columnIndex);
}
@Override
public float getFloat(int columnIndex) {
checkPosition();
return mWindow.getFloat(mPos, columnIndex);
}
@Override
public double getDouble(int columnIndex) {
checkPosition();
return mWindow.getDouble(mPos, columnIndex);
}
@Override
public boolean isNull(int columnIndex) {
checkPosition();
return mWindow.getType(mPos, columnIndex) == Cursor.FIELD_TYPE_NULL;
}
/**
* @deprecated Use {@link #getType}
*/
@Deprecated
public boolean isBlob(int columnIndex) {
return getType(columnIndex) == Cursor.FIELD_TYPE_BLOB;
}
/**
* @deprecated Use {@link #getType}
*/
@Deprecated
public boolean isString(int columnIndex) {
return getType(columnIndex) == Cursor.FIELD_TYPE_STRING;
}
/**
* @deprecated Use {@link #getType}
*/
@Deprecated
public boolean isLong(int columnIndex) {
return getType(columnIndex) == Cursor.FIELD_TYPE_INTEGER;
}
/**
* @deprecated Use {@link #getType}
*/
@Deprecated
public boolean isFloat(int columnIndex) {
return getType(columnIndex) == Cursor.FIELD_TYPE_FLOAT;
}
@Override
public int getType(int columnIndex) {
checkPosition();
return mWindow.getType(mPos, columnIndex);
}
@Override
protected void checkPosition() {
super.checkPosition();
if (mWindow == null) {
throw new StaleDataException("Attempting to access a closed CursorWindow." +
"Most probable cause: cursor is deactivated prior to calling this method.");
}
}
@Override
public CursorWindow getWindow() {
return mWindow;
}
/**
* Sets a new cursor window for the cursor to use.
* <p>
* The cursor takes ownership of the provided cursor window; the cursor window
* will be closed when the cursor is closed or when the cursor adopts a new
* cursor window.
* </p><p>
* If the cursor previously had a cursor window, then it is closed when the
* new cursor window is assigned.
* </p>
*
* @param window The new cursor window, typically a remote cursor window.
*/
public void setWindow(CursorWindow window) {
if (window != mWindow) {
closeWindow();
mWindow = window;
}
}
/**
* Returns true if the cursor has an associated cursor window.
*
* @return True if the cursor has an associated cursor window.
*/
public boolean hasWindow() {
return mWindow != null;
}
/**
* Closes the cursor window and sets {@link #mWindow} to null.
* @hide
*/
protected void closeWindow() {
if (mWindow != null) {
mWindow.close();
mWindow = null;
}
}
/**
* If there is a window, clear it.
* Otherwise, creates a new window.
*
* @param name The window name.
* @hide
*/
protected void clearOrCreateWindow(String name) {
if (mWindow == null) {
mWindow = new CursorWindow(name);
} else {
mWindow.clear();
}
}
/** @hide */
@Override
protected void onDeactivateOrClose() {
super.onDeactivateOrClose();
closeWindow();
}
}
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