aQute.bnd.properties.CopyOnWriteTextStore Maven / Gradle / Ivy
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package aQute.bnd.properties;
/**
* Copy-on-write ITextStore wrapper.
*
* This implementation uses an unmodifiable text store for the initial content.
* Upon first modification attempt, the unmodifiable store is replaced with a
* modifiable instance which must be supplied in the constructor.
*
*
* This class is not intended to be subclassed.
*
*
* @since 3.2 @noextend This class is not intended to be subclassed by clients.
*/
public class CopyOnWriteTextStore implements ITextStore {
/**
* An unmodifiable String based text store. It is not possible to modify the
* content other than using {@link #set}. Trying to {@link #replace} a text
* range will throw an UnsupportedOperationException.
*/
private static class StringTextStore implements ITextStore {
/** Represents the content of this text store. */
private String fText = ""; //$NON-NLS-1$
/**
* Create an empty text store.
*/
StringTextStore() {
super();
}
/**
* Create a text store with initial content.
*
* @param text the initial content
*/
StringTextStore(String text) {
super();
set(text);
}
/*
* @see org.eclipse.jface.text.ITextStore#get(int)
*/
@Override
public char get(int offset) {
return fText.charAt(offset);
}
/*
* @see org.eclipse.jface.text.ITextStore#get(int, int)
*/
@Override
public String get(int offset, int length) {
return fText.substring(offset, offset + length);
}
/*
* @see org.eclipse.jface.text.ITextStore#getLength()
*/
@Override
public int getLength() {
return fText.length();
}
/*
* @see org.eclipse.jface.text.ITextStore#replace(int, int,
* java.lang.String)
*/
@Override
public void replace(int offset, int length, String text) {
// modification not supported
throw new UnsupportedOperationException();
}
/*
* @see org.eclipse.jface.text.ITextStore#set(java.lang.String)
*/
@Override
public void set(String text) {
fText = text != null ? text : ""; //$NON-NLS-1$
}
}
/** The underlying "real" text store */
protected ITextStore fTextStore = new StringTextStore();
/** A modifiable ITextStore instance */
private final ITextStore fModifiableTextStore;
/**
* Creates an empty text store. The given text store will be used upon first
* modification attempt.
*
* @param modifiableTextStore a modifiable ITextStore instance,
* may not be null
*/
public CopyOnWriteTextStore(ITextStore modifiableTextStore) {
fTextStore = new StringTextStore();
fModifiableTextStore = modifiableTextStore;
}
/*
* @see org.eclipse.jface.text.ITextStore#get(int)
*/
@Override
public char get(int offset) {
return fTextStore.get(offset);
}
/*
* @see org.eclipse.jface.text.ITextStore#get(int, int)
*/
@Override
public String get(int offset, int length) {
return fTextStore.get(offset, length);
}
/*
* @see org.eclipse.jface.text.ITextStore#getLength()
*/
@Override
public int getLength() {
return fTextStore.getLength();
}
/*
* @see org.eclipse.jface.text.ITextStore#replace(int, int,
* java.lang.String)
*/
@Override
public void replace(int offset, int length, String text) {
if (fTextStore != fModifiableTextStore) {
String content = fTextStore.get(0, fTextStore.getLength());
fTextStore = fModifiableTextStore;
fTextStore.set(content);
}
fTextStore.replace(offset, length, text);
}
/*
* @see org.eclipse.jface.text.ITextStore#set(java.lang.String)
*/
@Override
public void set(String text) {
fTextStore = new StringTextStore(text);
fModifiableTextStore.set(""); //$NON-NLS-1$
}
}