NewFieldResolver.java

package org.eclipse.jdt.postfixcompletion.resolver;

import java.util.List;

import org.eclipse.jdt.internal.corext.template.java.JavaVariable;
import org.eclipse.jdt.internal.ui.text.template.contentassist.MultiVariable;
import org.eclipse.jdt.postfixcompletion.core.JavaStatementPostfixContext;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.templates.TemplateContext;
import org.eclipse.jface.text.templates.TemplateVariable;
import org.eclipse.jface.text.templates.TemplateVariableResolver;
import org.eclipse.text.edits.TextEdit;

@SuppressWarnings("restriction")
public class NewFieldResolver extends TemplateVariableResolver {
	
	private static final int PUBLIC_ARG = 1;
	private static final boolean PUBLIC_DEFAULT_VALUE = false;
	private static final int FORCE_STATIC_ARG = 2;
	private static final boolean FORCE_STATIC_DEFAULT_VALUE = false;
	private static final int FINAL_FIELD_ARG = 3;
	private static final boolean FINAL_FIELD_DEFAULT_VALUE = false;
	private static final int INIT_VALUE_ARG = 4;
	private static final boolean INIT_VALUE_DEFAULT_VALUE = false;

	private final String defaultType;

	public NewFieldResolver() {
		this("java.lang.Object"); //$NON-NLS-1$
	}

	NewFieldResolver(String defaultType) {
		this.defaultType = defaultType;
	}

	/*
	 * @see org.eclipse.jface.text.templates.TemplateVariableResolver#resolve(org.eclipse.jface.text.templates.TemplateVariable, org.eclipse.jface.text.templates.TemplateContext)
	 */
	@SuppressWarnings("unchecked")
	@Override
	public void resolve(TemplateVariable variable, TemplateContext context) {
		List<String> params = variable.getVariableType().getParams();
		String param;
		if (params.size() == 0)
			param = defaultType;
		else
			param = params.get(0);
		
		JavaStatementPostfixContext jc = (JavaStatementPostfixContext) context;
		
		TemplateVariable ref = jc.getTemplateVariable(param);
		
		MultiVariable mv = (MultiVariable) variable;
		
		String type = param;
		
		if (ref instanceof MultiVariable) {
			// Reference is another variable
			JavaVariable refVar = (JavaVariable) ref;
			jc.addDependency(refVar, mv);

			type = refVar.getParamType();
		}
		
		boolean initValue = getInitValueParam(params);
		boolean forceStatic = getForceStaticParam(params);
		boolean publicField = getPublicParam(params);
		boolean finalField = getFinalField(params);

		String newType = type;
		String[] names = jc.suggestFieldName(newType, finalField, forceStatic);
		
		mv.setChoices(names);
		
		TextEdit te = jc.addField(newType, names[0], publicField, forceStatic, finalField, (initValue && ref instanceof JavaVariable) ? getValueFromVariable((JavaVariable) ref) : null);
		if (te != null) {
			jc.markAsUsed(names[0]);
			// We can apply it to the context
			jc.applyTextEdit(te);
			mv.setResolved(true);
			
			jc.registerOutOfRangeOffset(mv, findAbsolutePositionOfFieldNameBeginning(jc.getDocument(), te, names[0]) - jc.getAffectedSourceRegion().getOffset());
		} else {
			// Field was not created so better do nothing
		}
	}
	
	private boolean getPublicParam(List<String> params) {
		if (params.size() >= PUBLIC_ARG + 1) {
			String val = params.get(PUBLIC_ARG);
			return convertBooleanStringParam(val);
		}
		return PUBLIC_DEFAULT_VALUE;
	}
	
	private boolean getForceStaticParam(List<String> params) {
		if (params.size() >= FORCE_STATIC_ARG + 1) {
			String val = params.get(FORCE_STATIC_ARG);
			return convertBooleanStringParam(val);
		}
		return FORCE_STATIC_DEFAULT_VALUE;
	}
	
	private boolean getInitValueParam(List<String> params) {
		if (params.size() >= INIT_VALUE_ARG + 1) {
			String val = params.get(INIT_VALUE_ARG);
			return convertBooleanStringParam(val);
		}
		return INIT_VALUE_DEFAULT_VALUE;
	}
	
	private boolean getFinalField(List<String> params) {
		if (params.size() >= FINAL_FIELD_ARG + 1) {
			String val = params.get(FINAL_FIELD_ARG);
			return convertBooleanStringParam(val);
		}
		return FINAL_FIELD_DEFAULT_VALUE;
	}
	
	private String getValueFromVariable(JavaVariable var) {
		for (String s : var.getValues()) {
			if (s != null && s.trim().length() > 0) {
				return s;
			}
		}
		return null;
	}
	
	private boolean convertBooleanStringParam(String value) {
		if ("true".equals(value)) {
			return true;
		} else {
			return false;
		}
	}
	
	private int findAbsolutePositionOfFieldNameBeginning(IDocument doc, TextEdit te, String name) {
		try {
			String temp = doc.get(te.getOffset(), te.getLength());
			if (temp.contains("=")) {
				temp = temp.substring(0, temp.indexOf("="));
			}
			int nameOcc = temp.lastIndexOf(name);
			if (nameOcc != -1) {
				return te.getOffset() + nameOcc;
			}
			// Variable name not included
			// We try if we can determine the position with some basic logic
			// This case should not happen but it's a good idea to have a fallback
			int offset = temp.length();
			boolean semiColonFound = false;
			while (offset >= 0 && semiColonFound == false) {
				if (temp.charAt(offset) == ' ' && semiColonFound) return te.getOffset() + offset;
				if (temp.charAt(offset) == ';') semiColonFound = true;
			}
			
		} catch (BadLocationException e) {

		}
		return te.getOffset();
	}
}